Volcano Hazards Program Office

Volcano Updates

Semisopochnoi Advisory Level = WATCH Aviation Color Code = ORANGE. As of 2021-10-22 21:13:10 UTC, AVO Semisopochnoi ORANGE/WATCH - Minor explosions occurred frequently throughout the past week, producing low-level ash emissions. Change to current status on 2021-09-21 04:12:47 UTC from Alert Level WARNING and Aviation Color Code RED
For more information, see: https://volcanoes.usgs.gov/vhp/hans_notice.html?notice_identifier=DOI-USGS-AVO-2021-10-22T11:25:09-08:00
Great Sitkin Advisory Level = WATCH Aviation Color Code = ORANGE. As of 2021-10-22 21:13:10 UTC, AVO Great Sitkin ORANGE/WATCH - Lava dome growth continued, with flow lobes overtopping the south and west crater rim and extending downslope. Change to current status on 2021-07-23 22:25:55 UTC from Alert Level ADVISORY and Aviation Color Code YELLOW
For more information, see: https://volcanoes.usgs.gov/vhp/hans_notice.html?notice_identifier=DOI-USGS-AVO-2021-10-22T11:25:09-08:00
Pavlof Advisory Level = WATCH Aviation Color Code = ORANGE. As of 2021-10-22 21:13:10 UTC, AVO Pavlof ORANGE/WATCH - Small explosions detected throughout the week in geophysical and web camera data. Change to current status on 2021-08-05 17:55:02 UTC from Alert Level ADVISORY and Aviation Color Code YELLOW
For more information, see: https://volcanoes.usgs.gov/vhp/hans_notice.html?notice_identifier=DOI-USGS-AVO-2021-10-22T11:25:09-08:00
Kilauea Advisory Level = WATCH Aviation Color Code = ORANGE. As of 2021-10-22 18:27:44 UTC, HVO Kilauea ORANGE/WATCH - Kīlauea volcano is erupting; all lava activity is confined within Halemaʻumaʻu, in Hawai‘i Volcanoes National Park. Change to current status on 2021-10-05 02:52:01 UTC from Alert Level WATCH and Aviation Color Code ORANGE
For more information, see: https://volcanoes.usgs.gov/vhp/hans_notice.html?notice_identifier=DOI-USGS-HVO-2021-10-22T11:17:34-07:00
Mauna Loa Advisory Level = ADVISORY Aviation Color Code = YELLOW. As of 2021-10-21 21:54:32 UTC, HVO Mauna Loa YELLOW/ADVISORY - Mauna Loa is not erupting. Seismicity remains at background. Change to current status on 2019-07-02 17:40:18 UTC from Alert Level NORMAL and Aviation Color Code GREEN
For more information, see: https://volcanoes.usgs.gov/vhp/hans_notice.html?notice_identifier=DOI-USGS-HVO-2021-10-21T14:50:46-07:00

ALASKA VOLCANO OBSERVATORY WEEKLY UPDATE
U.S. Geological Survey
Friday, October 22, 2021, 1:13 PM AKDT (Friday, October 22, 2021, 21:13 UTC)


SEMISOPOCHNOI VOLCANO (VNUM #311060)
51°55'44" N 179°35'52" E, Summit Elevation 2625 ft (800 m)
Current Volcano Alert Level: WATCH
Current Aviation Color Code: ORANGE

The north crater of Mount Cerberus on Semisopochnoi Island remained active, and minor explosions were detected multiple times a day in geophysical and remote sensing data throughout the week. Low-level ash emissions were observed in web camera views regularly during clear weather. Ash plumes up to ~5,000 ft above sea level were observed most days in satellite imagery and typically dissipated within 100 km (62 miles) of the volcano. The longest plume extended up to ~250 km (~155 miles) on October 19.

Small eruptions producing minor ash deposits within the vicinity of the active north crater of Mount Cerberus and ash clouds under 10,000 feet above sea level have characterized the recent activity and show no signs of abating.

Semisopochnoi is monitored by local seismic and infrasound sensors, satellite data, web cameras, and remote infrasound and lightning networks.


Remote Semisopochnoi volcano occupies the largest, young volcanic island in the western Aleutians. The volcano is dominated by a 5-mile (8-km) diameter caldera that contains a small lake and several post-caldera cones and craters. The age of the caldera is not known with certainty but is likely early Holocene. Prior to 2018, the previous known historical eruption of Semisopochnoi occurred in 1987, probably from Sugarloaf Peak on the south coast of the island, but details are lacking. Another prominent, young post-caldera landform is Mount Cerberus, a three-peaked cone cluster in the southwest part of the caldera. The island is uninhabited and part of the Alaska Maritime National Wildlife Refuge. It is located 40 miles (65 km) northeast of Amchitka Island and 130 miles (200 km) west of Adak.

GREAT SITKIN VOLCANO (VNUM #311120)
52°4'35" N 176°6'39" W, Summit Elevation 5709 ft (1740 m)
Current Volcano Alert Level: WATCH
Current Aviation Color Code: ORANGE

Lava effusion continued this week at Great Sitkin, and lava fills more than half of the summit crater. Satellite imagery through October 20 showed that two lobes of lava, flowing over low points on the crater rim, extend downslope ~500 m (1,600 feet) to the south and west. Lava has also reached the crater rim on its northern periphery. In a few areas, the lava has advanced over snow and is advancing into the glacial ice to the east, but no significant steaming or ponding of water has been observed. This indicates that melt rates are probably low and there are no indications of any imminent hydrologic hazards.

The lava lobes that have overtopped the summit crater rim are flowing into small valleys developed on the volcanic edifice. The terrain is steep in these areas, and blocks of lava and lava rubble could detach from the terminus of the flow lobes without warning and form small rock avalanches in these valleys. Such avalanches may liberate ash and gas and could travel several hundred meters beyond the lava flows; they would be hazardous to anyone in those areas. Satellite imagery shows such a blocky deposit extending downslope beyond the terminus of the west flow lobe.

Local geophysical and web camera data have been unavailable since October 16 due to a power outage in Adak, Alaska, that has not yet been resolved. No explosive activity or ash emissions have been detected in regional seismic, infrasound, or satellite data.

There is no indication of how long lava effusion will continue during the current eruption, and it is possible that explosive activity could occur with little or no warning.

Great Sitkin Volcano is monitored by local seismic and infrasound sensors, satellite data, web cameras, and remote infrasound and lightning networks.


Great Sitkin Volcano is a basaltic andesite volcano that occupies most of the northern half of Great Sitkin Island, a member of the Andreanof Islands group in the central Aleutian Islands. It is located 43 km (26 miles) east of the community of Adak. The volcano is a composite structure consisting of an older dissected volcano and a younger parasitic cone with a 3-km-diameter summit crater. A steep-sided lava dome, emplaced during the most recent significant eruption in 1974, occupies the center of the crater. That eruption produced at least one ash cloud that likely exceeded an altitude of 25,000 ft above sea level. A poorly documented eruption occurred in 1945, also producing a lava dome that was partially destroyed in the 1974 eruption. Within the past 280 years a large explosive eruption produced pyroclastic flows that partially filled the Glacier Creek valley on the southwest flank.

PAVLOF VOLCANO (VNUM #312030)
55°25'2" N 161°53'37" W, Summit Elevation 8261 ft (2518 m)
Current Volcano Alert Level: WATCH
Current Aviation Color Code: ORANGE

Seismicity was elevated throughout the past week at Pavlof Volcano, and small explosions were detected at least once per day in seismic and infrasound data. Satellite and web camera views were mostly obscured by clouds, but localized, low-level ash emissions up to 10,000 ft above sea level were detected following these explosions in occasional clear web camera views.

The explosions that have occurred during the current period of activity at Pavlof have been short-lived, with ash deposits confined to the flanks of the volcano. Eruptive activity is focused at a vent on the upper southeast flank of the volcano, near the location of the eruptive vent in 2007. The level of unrest at Pavlof can change quickly and the progression to more significant eruptive activity can occur with little or no warning.

Pavlof is monitored by local seismic and infrasound sensors, satellite data, web cameras, and remote infrasound and lightning networks.


Pavlof Volcano is a snow- and ice-covered stratovolcano located on the southwestern end of the Alaska Peninsula about 953 km (592 mi) southwest of Anchorage. The volcano is about 7 km (4.4 mi) in diameter and has active vents on the north and east sides close to the summit. With over 40 historic eruptions, it is one of the most consistently active volcanoes in the Aleutian arc. Eruptive activity is generally characterized by sporadic Strombolian lava fountaining continuing for a several-month period. Ash plumes as high as 49,000 ft ASL have been generated by past eruptions of Pavlof, and during the March 2016 eruption, ash plumes as high as 40,000 feet above sea level were generated and the ash was tracked in satellite data as distant as eastern Canada. The nearest community, King Cove, is located 48 km (30 miles) to the southwest of Pavlof.

CLEVELAND VOLCANO (VNUM #311240)
52°49'20" N 169°56'42" W, Summit Elevation 5676 ft (1730 m)
Current Volcano Alert Level: UNASSIGNED
Current Aviation Color Code: UNASSIGNED

No significant seismic or infrasound activity was detected over the past week. Weakly elevated surface temperatures were observed in rare clear nighttime satellite views on October 16 and 18 this week. Clouds otherwise obscured most satellite and web camera views during the week. A sustained decline in volcanic unrest at Cleveland volcano over the past few months prompted the Alaska Volcano Observatory to downgrade the Aviation Color Code and Volcano Alert Level from YELLOW/ADVISORY to UNASSIGNED/UNASSIGNED on October 20, 2021.

Despite the current pause, the eruptive period at Cleveland, dating back to 2001, remains ongoing and future explosions are likely. These occur without warning and typically generate small clouds of volcanic ash that are a hazard in the immediate vicinity of the volcano, though more significant ash emissions are possible.

Cleveland volcano is currently monitored by only one seismic station, which restricts AVO's ability to precisely locate earthquakes and detect precursory unrest that may lead to an explosive eruption. Rapid detection of an ash-producing eruption may be possible using a combination of seismic, local and regional infrasound, lightning, and satellite data.


Cleveland volcano forms the western portion of Chuginadak Island, a remote and uninhabited island in the east central Aleutians. The volcano is located about 45 miles (75 km) west of the community of Nikolski, and 940 miles (1500 km) southwest of Anchorage. The most recent significant period of eruption began in February 2001 and produced 3 explosive events that generated ash clouds as high as 39,000 ft (11.8 km) above sea level. The 2001 eruption also produced a lava flow and hot avalanche that reached the sea. Since then, Cleveland has been intermittently active producing small lava flows, often followed by explosions that generate small ash clouds generally below 20,000 ft (6 km) above sea level. These explosions also launch debris onto the slopes of the cone producing hot pyroclastic avalanches and lahars that sometimes reach the coastline.

OTHER ALASKA VOLCANOES

Information on all Alaska volcanoes is available at : http://www.avo.alaska.edu.

For definitions of Aviation Color Codes and Volcano Alert Levels, see: http://www.avo.alaska.edu/color_codes.php

SUBSCRIBE TO VOLCANO ALERT MESSAGES by email: http://volcanoes.usgs.gov/vns/

FOLLOW AVO ON FACEBOOK: https://facebook.com/alaska.avo

FOLLOW AVO ON TWITTER: https://twitter.com/alaska_avo

CONTACT INFORMATION:

Michelle Coombs, Scientist-in-Charge, USGS, mcoombs@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAF, dfee1@alaska.edu (907) 322-4085


The Alaska Volcano Observatory is a cooperative program of the U.S. Geological Survey, the University of Alaska Fairbanks Geophysical Institute, and the Alaska Division of Geological and Geophysical Surveys.

CALIFORNIA VOLCANO OBSERVATORY WEEKLY UPDATE
U.S. Geological Survey
Tuesday, October 19, 2021, 10:11 AM PDT (Tuesday, October 19, 2021, 17:11 UTC)


Monitored CALIFORNIA VOLCANOES
Current Volcano Alert Level: all NORMAL
Current Aviation Color Code: all GREEN


Activity Update: All volcanoes monitored by CalVO using telemetered, real-time sensor networks exhibit normal levels of background seismicity and deformation. Volcanoes monitored include Mount Shasta, Medicine Lake Volcano, Clear Lake Volcanic Field, Lassen Volcanic Center, Long Valley Volcanic Region, Coso Volcanic Field, Ubehebe Craters, and Salton Buttes.

Observations for October 11, 2021 (0000h PDT) through October 17, 2021 (2359h PDT):

Clear Lake Volcanic Field:
No earthquakes at or above M1.0 were detected. As is typical, moderate levels of seismicity were recorded at the Geysers geothermal steam field south of the Clear Lake Volcanic Field; 61 earthquakes at or above M1.0 were detected, with the largest event measuring M2.6.
Lassen Volcanic Center: No earthquakes at or above M1.0 were detected.
Long Valley Volcanic Region: 3 earthquakes at or above M1.0 were detected in the Long Valley Caldera, with the largest being M2.2. No earthquakes at or above M1.0 were detected at Mammoth Mountain. 3 earthquakes at or above M1.0 were detected in the Mono-Inyo Craters, with the largest measuring M2.2. As is typical, moderate levels of seismicity were observed south of the caldera in the Sierra Nevada range; 5 earthquakes at or above M1.0 were detected, with the largest event measuring M3.0.
Mount Shasta: One earthquake at or above M1.0 was detected with a magnitude of 1.9.
Medicine Lake: No earthquakes at or above M1.0 were detected.
Salton Buttes: Four earthquakes at or above M1.0 were detected, with the largest measuring M1.6.
Coso Volcanic Field: One earthquake at or above M1.0 was detected, measuring M1.1.
Ubehebe Craters: No earthquakes at or above M1.0 were detected.


These earthquake counts are preliminary and subject to change as the earthquakes are reviewed by seismologists. The U.S. Geological Survey will continue to monitor these volcanoes closely and will issue additional updates and changes in alert level as warranted. For a definition of alert levels see http://volcanoes.usgs.gov/activity/alertsystem/icons.php.

As part of the U.S. Geological Survey's Volcano Hazards Program, the California Volcano Observatory monitors the volcanoes of California and Nevada and advances scientific understanding of volcanic processes in order to reduce the harmful impacts of volcanic activity. For additional USGS CalVO volcano information, background, images, and other graphics visit http://volcanoes.usgs.gov/observatories/calvo/. For general information on the USGS Volcano Hazard Program visit http://volcanoes.usgs.gov. Statewide seismic information for California and Nevada can be found at https://earthquake.usgs.gov/earthquakes/map/.



CONTACT INFORMATION:

askCalVO@usgs.gov

CASCADES VOLCANO OBSERVATORY WEEKLY UPDATE
U.S. Geological Survey
Friday, October 22, 2021, 12:00 PM PDT (Friday, October 22, 2021, 19:00 UTC)


CASCADE RANGE VOLCANOES
Current Volcano Alert Level: NORMAL
Current Aviation Color Code: GREEN

Activity Update: All volcanoes in the Cascade Range of Oregon and Washington are at normal background levels of activity. These include Mount Baker, Glacier Peak, Mount Rainier, Mount St. Helens, and Mount Adams in Washington State; and Mount Hood, Mount Jefferson, Three Sisters, Newberry, and Crater Lake in Oregon.

Recent Observations: Earthquakes were located at Mount Rainier, Mount St. Helens, and Mount Hood this past week, consistent with background seismicity levels at each volcano. At Mount Hood a small swarm of earthquakes occurred between October 17-19, with earthquakes located under the summit (a common location for Mount Hood earthquakes). The Pacific Northwest Seismic Network (PNSN) located a total of 37 earthquakes during that time window, with depths ranging from 3-6 km (2-4 miles) below the surface. Most earthquakes had magnitudes below 1, with the largest being a magnitude of 2.5. Such swarms are not unusual at Mount Hood and are viewed by CVO and the PNSN as part of normal background seismicity at the volcano.


The U.S. Geological Survey and Pacific Northwest Seismic Network (PNSN) continue to monitor these volcanoes closely and will issue additional updates and changes in alert level as warranted.

For images, graphics, and general information on Cascade Range volcanoes: https://www.usgs.gov/observatories/cascades-volcano-observatory
For seismic information on Oregon and Washington volcanoes: http://www.pnsn.org/volcanoes
For information on USGS volcano alert levels and notifications: https://www.usgs.gov/natural-hazards/volcano-hazards/notifications

HAWAIIAN VOLCANO OBSERVATORY DAILY UPDATE
U.S. Geological Survey
Friday, October 22, 2021, 8:27 AM HST (Friday, October 22, 2021, 18:27 UTC)


KILAUEA VOLCANO (VNUM #332010)
19°25'16" N 155°17'13" W, Summit Elevation 4091 ft (1247 m)
Current Volcano Alert Level: WATCH
Current Aviation Color Code: ORANGE

Activity Summary:   Kīlauea volcano is erupting. As of this morning, October 22, 2021, lava continues to erupt from a single vent in the western wall of Halemaʻumaʻu crater. All lava activity is confined within Halemaʻumaʻu crater in Hawai‘i Volcanoes National Park. Seismic activity and volcanic gas emission rates remain elevated.

Summit Observations: Sulfur dioxide (SO2) emission rates remain high, with a preliminary emission rate for October 21, 2021, of approximately 2,600 tonnes per day. No significant changes seen in summit tilt or GPS observations. Earthquake activity remains below background and volcanic tremor remains elevated since the beginning of the eruption.

Halemaʻumaʻu Lava Lake Observations: Lava continues to erupt from a single vent in the western wall of Halemaʻumaʻu crater. The western end of the lake showed a maximum elevation of approximately 791 meters (2595 ft) above sea level by HVO’s permanent laser rangefinder on October 22, 2021, which is is the same as yesterday, and a total increase of about 47 meters (154 ft) since lava emerged on September 29. The total erupted volume since the beginning of the eruption was estimated to be about 19.9 million cubic meters (5.3 billion gallons) on October 15. The western vent had consistent fountain heights up to 5 m (16 ft) with occasional bursts up to 10 m (33 ft) observed by field crews on October 21. The lava lake is not level across its surface due to the location of the vent in the western end. There is about 7 meters (23 feet) elevation difference between the active west and stagnant east part of the lake.

East Rift Zone Observations: No unusual activity has been noted in the Kīlauea East Rift Zone. Ground deformation measurements in the upper East Rift Zone area—between the summit and Puʻuʻōʻo—suggest that refilling of magma since late August, 2021 has slowed or decreased slightly. SO2 and hydrogen sulfide (H2S) emissions from Puʻuʻōʻō were below instrumental detection levels when last measured on January 7, 2021.

Hazard Analysis: This new eruption at Kīlauea’s summit is occurring within a closed area of Hawai'i Volcanoes National Park. Therefore, high levels of volcanic gas are the primary hazard of concern, as this hazard can have far-reaching effects down-wind. Large amounts of volcanic gas—primarily water vapor (H2O), carbon dioxide (CO2), and sulfur dioxide (SO2)—are continuously released during eruptions of Kīlauea Volcano. As SO2 is released from the summit, it reacts in the atmosphere to create the visible haze known as vog (volcanic smog) that has been observed downwind of Kīlauea. Vog creates the potential for airborne health hazards to residents and visitors, damages agricultural crops and other plants, and affects livestock. For more information on gas hazards at the summit of Kīlauea, please see: https://pubs.er.usgs.gov/publication/fs20173017. Vog information can be found at https://vog.ivhhn.org/. 

Additional hazards include Pele's hair and other lightweight volcanic glass fragments from the lava fountains that will fall downwind of the fissure vents and dust the ground within a few hundred meters (yards) of the vent (s). Strong winds may waft lighter particles to greater distances. Residents should minimize exposure to these volcanic particles, which can cause skin and eye irritation. 

Other significant hazards also remain around Kīlauea caldera from Halemaʻumaʻu crater wall instability, ground cracking, and rockfalls that can be enhanced by earthquakes within the area closed to the public. This underscores the extremely hazardous nature of Kīlauea caldera rim surrounding Halemaʻumaʻu crater, an area that has been closed to the public since early 2008. 

For discussion of Kīlauea hazards, please see: https://www.usgs.gov/observatories/hawaiian-volcano-observatory/hazards 

Please see the Hawaiʻi Volcanoes National Park website for visitor information: https://www.nps.gov/havo/index.htm. Visitors to Hawai'i Volcanoes National Park should note that under southerly (non-trade) wind conditions, there is potential for a dusting of powdery to gritty ash composed of volcanic glass and rock fragments. These ashfalls represent a minor hazard, but visitors should be aware that dustings of ash at areas around the Kīlauea summit are possible. 

The Hawaiian Volcano Observatory (HVO) continues to closely monitor Kīlauea Volcano.

HVO will continue to issue daily Kīlauea Volcano updates until further notice. Additional messages will be issued as needed.


More Information:
Kīlauea activity summary also available by phone: (808) 967-8862
Kīlauea webcam images: https://www.usgs.gov/volcanoes/kilauea/webcams
Kīlauea photos/video: https://www.usgs.gov/volcanoes/kilauea/photo-video-chronology
Kīlauea lava-flow maps: https://www.usgs.gov/volcanoes/kilauea/maps
Kīlauea FAQs: https://www.usgs.gov/volcanoes/kilauea/faqs

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Subscribe to these messages: https://volcanoes.usgs.gov/vns2/

Summary of volcanic hazards from eruptions: https://www.usgs.gov/observatories/hawaiian-volcano-observatory/hazards

Recent earthquakes in Hawaiʻi (map and list): https://www.usgs.gov/observatories/hawaiian-volcano-observatory/earthquakes

Explanation of Volcano Alert Levels and Aviation Color Codes: https://www.usgs.gov/natural-hazards/volcano-hazards/about-alert-levels

CONTACT INFORMATION:

askHVO@usgs.gov

The Hawaiian Volcano Observatory is one of five volcano observatories within the U.S. Geological Survey and is responsible for monitoring volcanoes and earthquakes in Hawaiʻi.

NORTHERN MARIANA ISLANDS VOLCANO OBSERVATORY WEEKLY UPDATE
U.S. Geological Survey
Friday, October 22, 2021, 10:03 AM ChST (Friday, October 22, 2021, 00:03 UTC)


Report prepared by the U.S. Geological Survey.

NORTHERN MARIANAS VOLCANOES

No eruptive activity or significant unrest was detected at any Northern Mariana Island volcanoes during the past week.

There have been no observations of significant eruptive activity or volcanic gas emissions at Pagan in the last week. It is unclear at this time whether the apparent pause in ash emission since September 6 indicates an end to eruptive activity or just a temporary hiatus. Further ash emissions are possible and could occur at any time.

Access to Pagan may be restricted by the CNMI government. Contact the EMO for the latest information.

Monitoring of Northern Mariana Islands Volcanoes

Northern Mariana Island volcanoes are monitored remotely with satellite data, an intermittently operational seismo-acoustic network on Saipan, distant seismic stations in Guam and Chichijima, Japan, and hydroacoustic data from Wake Island. These observations might detect significant explosive activity in the CNMI, but because of the absence of functional local ground-based monitoring stations at the volcanoes, we cannot provide advanced warning of activity.

Ground-based geophysical monitoring data from stations on Anatahan and Sarigan islands have been unavailable since storm damage in August, 2017. Current logistical challenges in the CNMI prevent visiting these sites to make repairs. A timeline for returning these stations to operation is uncertain. Due to a lack of direct geophysical monitoring on the islands, Anatahan and Sarigan volcano alert levels are designated UNASSIGNED.

Other volcanoes in the CNMI including Farallon de Pajaros, Supply Reef, Maug, Asuncion, Agrigan, Pagan, Almagan, and Guguan are not seismically monitored and are normally designated UNASSIGNED, absent other observations of activity.


For definitions of Aviation Color Codes and Volcano Alert Levels, see: http://volcanoes.usgs.gov/activity/alertsystem/index.php

SUBSCRIBE TO VOLCANO ALERT MESSAGES by email: http://volcanoes.usgs.gov/vns/

CONTACT INFORMATION:
CNMI Homeland Security and Emergency Management
http://www.cnmihsem.gov.mp

USGS Northern Mariana Duty Scientist (808) 967-8815
http://volcano.wr.usgs.gov/cnmistatus.php

Satellite information, Washington VAAC
http://www.ssd.noaa.gov/VAAC/washington.html


CONTACT INFORMATION:

CNMI Homeland Security and Emergency Management
http://www.cnmihsem.gov.mp/

USGS Northern Mariana Duty Scientist (808) 967-8815
http://volcano.wr.usgs.gov/cnmistatus.php

Satellite information, Washington VAAC
http://www.ssd.noaa.gov/VAAC/washington.html

YELLOWSTONE VOLCANO OBSERVATORY MONTHLY UPDATE
U.S. Geological Survey
Friday, October 1, 2021, 1:32 PM MDT (Friday, October 1, 2021, 19:32 UTC)


YELLOWSTONE VOLCANO (VNUM #325010)
44°25'48" N 110°40'12" W, Summit Elevation 9203 ft (2805 m)
Current Volcano Alert Level: NORMAL
Current Aviation Color Code: GREEN

Recent work and news

Yellowstone Volcano Observatory scientists are gearing up for some of the last field work of the 2021 season. In the coming weeks, geophysicists will be conducting maintenance on the Norris temperature network to ensure that it remains operational throughout the winter, and also conducting a gravity survey, done every year to help detect changes in mass beneath the ground. They will also be recovering the 17 sites of the semipermanent GPS network—a set of temporary sites that supplement the continuous GPS network during summer months. These stations are deployed every May, after much of the snow melts, and are collected every October, before winter sets in. The GPS receivers are not connected to any radio telemetry, so they must be recovered to download and examine the data. The sites will be redeployed in May 2022.

After taking a month off, Steamboat Geyser erupted twice in September—on September 11 and 28—bringing the total number of eruptions for the year to 15. Eruptions are irregular and much less frequent than during the previous three summers, which may indicate that the geyser is trending toward a period of quiescence. This is typical behavior for Steamboat, with the geyser experiencing few-year periods of frequent eruptions separated by years to decades of very few eruptions.

Seismicity

During September 2021, the University of Utah Seismograph Stations, responsible for the operation and analysis of the Yellowstone Seismic Network, located 283 earthquakes in the Yellowstone National Park region. The largest event of the past month was a minor earthquake of magnitude 3.2 located 15.6 miles south of Old Faithful, Yellowstone National Park, on September 8 at 11:01 AM MDT.

September seismicity in Yellowstone was marked by 4 earthquake swarms.

1) A series of 153 earthquakes ~14 miles north-northeast of Old Faithful began September 16 and continued to the end of the month. The largest event (magnitude 1.8) occurred on September 22 at 06:53 PM MDT.

2) A small swarm of 17 earthquakes ~8 miles north-northeast of West Yellowstone, MT, began September 28 and continued to the end of the month. The largest event (magnitude 1.5) occurred September 29 at 07:42 MDT.

3) A small swarm of 16 earthquakes began September 29 and continued to the end of the month beneath Yellowstone Lake ~0.5 miles southwest of Dot Island. The largest event (magnitude 1.9) occurred September 30 at 00:05 AM MDT.

4) A small swarm of 14 earthquakes occurred September 8, located ~15.5 miles south of Old Faithful. The swarm included the largest event of the month (magnitude 3.2; detailed above).

Earthquake sequences like these are common and account for roughly 50% of the total seismicity in the Yellowstone region.

Yellowstone earthquake activity remains at background levels.

Ground deformation

Subsidence of Yellowstone Caldera, which has been ongoing since 2015, has paused during the summer months, reflecting seasonal groundwater recharge. Every summer, water from snow melt causes the ground to swell slightly, resulting in a pause in subsidence trends or even a minor amount of uplift (less than 1 cm / fraction of an inch). In the area of Norris Geyser Basin, no significant uplift or subsidence has been detected by a nearby GPS station since the start of 2020.

An example of GPS data can be found at http://www.unavco.org/instrumentation/networks/status/pbo/data/NRWY (click on Static Plots / Cleaned)



The Yellowstone Volcano Observatory (YVO) provides long-term monitoring of volcanic and earthquake activity in the Yellowstone National Park region. Yellowstone is the site of the largest and most diverse collection of natural thermal features in the world and the first National Park. YVO is one of the five USGS Volcano Observatories that monitor volcanoes within the United States for science and public safety.

YVO Member agencies: USGS, Yellowstone National Park, University of Utah, University of Wyoming, Montana State University, UNAVCO, Inc., Wyoming State Geological Survey, Montana Bureau of Mines and Geology, Idaho Geological Survey



CONTACT INFORMATION:

Michael Poland, Scientist-in-Charge
mpoland@usgs.gov

Volcano Observatory Notices for Aviation (VONA)

2021-10-20 - Shishaldin, Aviation Color Code: UNASSIGNED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20211020/2309Z)
(3) Volcano: Shishaldin (VNUM #311360)
(4) Current Color Code: UNASSIGNED
(5) Previous Color Code: GREEN
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2021/A949
(8) Volcano Location: N 54 deg 45 min W 163 deg 58 min
(9) Area: Aleutians
(10) Summit Elevation: 9373 ft (2857 m)
(11) Volcanic Activity Summary: The Shishaldin Volcano monitoring network has several outages affecting local GPS, seismic, and infrasound stations that are likely to persist through the winter months. Due to the impaired local monitoring stations, the Alaska Volcano Observatory is changing the Aviation Color Code and the Volcano Alert Level to UNASSIGNED/UNASSIGNED.

The Alaska Volcano Observatory continues to monitor Shishaldin with seismic, GPS, and infrasound instruments on nearby networks, as well as with Cold Bay web camera imagery and satellite data.
(12) Volcanic cloud height: not applicable
(13) Other volcanic cloud information: not applicable
(14) Remarks: Shishaldin Volcano, located near the center of Unimak Island in the eastern Aleutian Islands, is a spectacular symmetric cone with a base diameter of approximately 16 km (10 mi). A 200-m-wide (660 ft) funnel-shaped summit crater typically emits a steam plume and occasional small amounts of ash. Shishaldin is one of the most active volcanoes in the Aleutian volcanic arc, with at least 54 episodes of unrest including over 24 confirmed eruptions since 1775. Most eruptions are relatively small, although the April-May 1999 event generated an ash column that reached 45,000 ft above sea level.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS, mcoombs@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAF, dfee1@alaska.edu (907) 322-4085
(16) Next Notice:
2021-10-20 - Cleveland, Aviation Color Code: UNASSIGNED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20211020/2304Z)
(3) Volcano: Cleveland (VNUM #311240)
(4) Current Color Code: UNASSIGNED
(5) Previous Color Code: YELLOW
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2021/A950
(8) Volcano Location: N 52 deg 49 min W 169 deg 56 min
(9) Area: Aleutians
(10) Summit Elevation: 5676 ft (1730 m)
(11) Volcanic Activity Summary: A sustained decline in volcanic unrest at Cleveland volcano over the past few months has prompted the Alaska Volcano Observatory to downgrade the Aviation Color Code and Volcano Alert Level from YELLOW/ADVISORY to UNASSIGNED/UNASSIGNED.

Elevated seismicity, deformation within the summit crater, and thermal and gas emissions prompted raising the Aviation Color Code and Volcano Alert Level from UNASSIGNED/UNASSIGNED to YELLOW/ADVISORY on March 20, 2021. This activity continued over the summer, but all signs of unrest have ceased or declined in recent months. Elevated surface temperatures in the summit crater are still being observed at reduced frequency and strength. The last eruptive activity at Cleveland volcano was a short-lived explosion on the evening (local time) of June 1, 2020.

Despite the current pause, the eruptive period at Cleveland, dating back to 2001, remains ongoing and future explosions are likely. These occur without warning and typically generate small clouds of volcanic ash that are a hazard in the immediate vicinity of the volcano, though more significant ash emissions are possible.

Cleveland volcano is monitored with a limited real-time seismic network. This smaller network inhibits AVO's ability to detect precursory unrest that may lead to an explosive eruption. Rapid detection of an ash-producing eruption may be possible using a combination of seismic, infrasound, lightning, and satellite data.
(12) Volcanic cloud height: not applicable
(13) Other volcanic cloud information: not applicable
(14) Remarks: Cleveland volcano forms the western portion of Chuginadak Island, a remote and uninhabited island in the east central Aleutians. The volcano is located about 45 miles (75 km) west of the community of Nikolski, and 940 miles (1500 km) southwest of Anchorage. The most recent significant period of eruption began in February 2001 and produced 3 explosive events that generated ash clouds as high as 39,000 ft (11.8 km) above sea level. The 2001 eruption also produced a lava flow and hot avalanche that reached the sea. Since then, Cleveland has been intermittently active producing small lava flows, often followed by explosions that generate small ash clouds generally below 20,000 ft (6 km) above sea level. These explosions also launch debris onto the slopes of the cone producing hot pyroclastic avalanches and lahars that sometimes reach the coastline.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS, mcoombs@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAF, dfee1@alaska.edu (907) 322-4085
(16) Next Notice:
2021-10-05 - Kilauea, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20211005/0252Z)
(3) Volcano: Kilauea (VNUM #332010)
(4) Current Color Code: ORANGE
(5) Previous Color Code: RED
(6) Source: Hawaiian Volcano Observatory
(7) Notice Number: 2021/H273
(8) Volcano Location: N 19 deg 25 min W 155 deg 17 min
(9) Area: Hawaii
(10) Summit Elevation: 4091 ft (1247 m)
(11) Volcanic Activity Summary: Kīlauea volcano is erupting. At approximately 3:21 p.m. HST on September 29, 2021, an eruption began within Halemaʻumaʻu crater, within Kīlauea’s summit caldera in Hawai‘i Volcanoes National Park. The USGS Hawaiian Volcano Observatory (HVO) elevated Kīlauea’s volcano alert level to WARNING and its aviation color code to RED to assess the intensity of eruptive activity and identify associated hazards.  

Vigorous fountaining—with bursts up to 50–60 meters (164–197 ft)—produced significant amounts of pumice, Peleʻs hair, and fragments of volcanic glass that were deposited in areas downwind along the rim and beyond Halemaʻumaʻu crater. Over the past several days, a thick layer (approximately 27 meters or 89 ft) of molten lava has accumulated as a lava lake at the base of the crater, partially drowning the vents resulting in subdued fountaining. During the same time, the amount of sulfur dioxide (SO2) emitted has dropped from 85,000 tons per day (one metric ton equals 2,200 pounds) to 12,000 tons a day. Although the amount of gas and volcanic particle production has decreased since the eruption onset, they both remain significant local hazards within the plume. Concentrations of SO2 at the vents remain high (likely over 100 parts per million or ppm) and significantly elevated (5-10 ppm) at stations a few kilometers (a couple of miles) southwest of Halemaʻumaʻu.

The eruption is currently confined to Halemaʻumaʻu crater, within Hawai‘i Volcanoes National Park.  HVO does not see any indication of activity migrating elsewhere on Kīlauea volcano  and expects the eruption to remain confined to the summit region.

HVO is lowering Kīlauea’s volcano alert level to WATCH and its aviation color code to ORANGE, reflecting the less-hazardous nature of the ongoing eruption. 

For more information on gas hazards at the summit of Kīlauea, please see: https://pubs.er.usgs.gov/publication/fs20173017

For more information about volcanic ash hazards and precautions at Kīlauea, please see: http://hvo.wr.usgs.gov/hazards/FAQ_SO2-Vog-Ash/main.html
(12) Volcanic cloud height: 1000–2000 meters (3280–6562 ft)
(13) Other volcanic cloud information: Plume composed of SO2 and H2O with minor volcanic particles
(14) Remarks: Prognosis: 

It is unclear how long the current eruption will continue. Kīlauea summit eruptions over the past 200 years have lasted from less than a day to more than a decade. This ongoing eruption is similar to the most recent Kīlauea eruption, which was also confined to Halemaʻumaʻu crater and generated a lava lake; the most recent eruption lasted approximately five months, from December 2020 to May 2021. 

HVO is in constant communication with the National Park Service and Hawai‘i County Civil Defense and other agencies responsible for public safety. 

HVO scientists will continue to monitor Kīlauea volcano closely and will issue additional messages as warranted by changing activity. Stay informed about Kīlauea by following volcano updates and tracking current monitoring data on the HVO web page at https://www.usgs.gov/volcanoes/kilauea/volcano-updates

More Information:
Kīlauea activity summary also available by phone: (808) 967-8862
Kīlauea webcam images: https://www.usgs.gov/volcanoes/kilauea/webcams
Kīlauea photos/video: https://www.usgs.gov/volcanoes/kilauea/photo-video-chronology
Kīlauea lava-flow maps: https://www.usgs.gov/volcanoes/kilauea/maps
Kīlauea FAQs: https://www.usgs.gov/volcanoes/kilauea/faqs

Hazard Analysis: 

This new eruption at Kīlauea’s summit is occurring within a closed area of Hawaiʻi Volcanoes National Park. Therefore, high levels of volcanic gas and fine volcanic particles are the primary hazards of concern, as these hazards can have far-reaching effects downwind.

Large amounts of volcanic gas—including carbon dioxide (CO2) and sulfur dioxide (SO2)—are continuously released during eruptions of Kīlauea volcano. Concentrations of SO2 can be much greater than recommended exposure levels on Halemaʻumaʻu rim and extending several kilometers downwind; exposure to these elevated SO2 levels is considered hazardous and may cause breathing difficulties. Additional hazards include Pele's hair and other lightweight volcanic glass fragments from the lava fountains that can be entrained in the plume and fall several kilometers (miles) downwind of the fissure vents.

Strong winds may waft lighter particles to greater distances and impact surrounding communities. Residents should minimize exposure to fine volcanic particles, which can cause skin and eye irritation.  As the SO2 plume moves away from the vent, it reacts in the atmosphere to create the visible haze known as vog (volcanic air pollution) that has been observed downwind of Kīlauea. Vog creates the potential for airborne health hazards to residents and visitors, damages agricultural crops and other plants, and affects livestock. For more information on gas hazards at the summit of Kīlauea, please see: https://pubs.er.usgs.gov/publication/fs20173017. Vog information can be found at https://vog.ivhhn.org/.  

Other significant hazards also remain around Kīlauea caldera from Halemaʻumaʻu crater wall; ground instability, ground cracking, and rockfalls can be enhanced by earthquakes within the area closed to the public. This underscores the extremely hazardous nature of Kīlauea caldera rim surrounding Halemaʻumaʻu crater, an area that has been closed to the public since late 2007.  

For discussion of Kīlauea hazards, please see: https://www.usgs.gov/observatories/hawaiian-volcano-observatory/hazards.

Please see the Hawaiʻi Volcanoes National Park website for visitor information: https://www.nps.gov/havo/index.htm. Visitors to Hawaiʻi Volcanoes National Park should note that under southerly (non-trade) wind conditions, there is potential for ashfall—a dusting of powdery to gritty ash composed of volcanic glass and rock fragments. These ashfalls represent a minor hazard, but visitors should be aware that dustings of ash at areas around the Kīlauea summit are possible.  
(15) Contacts: askHVO@usgs.gov
(16) Next Notice: The Hawaiian Volcano Observatory (HVO) continues to closely monitor Kīlauea's seismicity, deformation, and gas emissions for any changes in activity. Kīlauea updates will be issued daily. Should volcanic activity change significantly a new VAN will be issued. Regularly scheduled updates are posted at https://www.usgs.gov/hvo.

Subscribe to these messages:
https://volcanoes.usgs.gov/vns2/

Recent earthquakes in Hawaiʻi (map and list): https://www.usgs.gov/observatories/hawaiian-volcano-observatory/earthquakes

Explanation of Volcano Alert Levels and Aviation Color Codes: https://www.usgs.gov/natural-hazards/volcano-hazards/about-alert-levels
2021-09-30 - Kilauea, Aviation Color Code: RED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20210930/0142Z)
(3) Volcano: Kilauea (VNUM #332010)
(4) Current Color Code: RED
(5) Previous Color Code: ORANGE
(6) Source: Hawaiian Volcano Observatory
(7) Notice Number: 2021/H262
(8) Volcano Location: N 19 deg 25 min W 155 deg 17 min
(9) Area: Hawaii
(10) Summit Elevation: 4091 ft (1247 m)
(11) Volcanic Activity Summary: Kīlauea volcano is erupting. At approximately 3:20 p.m. HST on September 29, 2021, the USGS Hawaiian Volcano Observatory (HVO) detected glow in Kīlauea summit webcam images indicating that an eruption has commenced within Halemaʻumaʻu crater in Kīlauea’s summit caldera, within Hawai‘i Volcanoes National Park. Webcam imagery shows fissures at the base of Halemaʻumaʻu crater generating lava flows on the surface of the lava lake that was active until May 2021.

The US Geological Survey Hawaiian Volcano Observatory (HVO) is elevating Kīlauea’s volcano alert level to from WATCH to WARNING and its aviation color code from ORANGE to RED as this new eruption and associated hazards are evaluated.   The activity is confined to Halemaʻumaʻu and the hazards will be reassessed as the eruption progresses.

USGS volcano alert levels and aviation color codes are explained here: https://www.usgs.gov/natural-hazards/volcano-hazards/about-alert-levels 

The opening phases of eruptions are dynamic and uncertain. HVO continues to monitor the volcano closely and will report any significant changes in future notices. 

Stay informed about Kīlauea by following volcano updates and tracking current monitoring data on the HVO web page (https://www.usgs.gov/volcanoes/kilauea/volcano-updates) or by signing up to receive updates by email at this site: https://volcanoes.usgs.gov/vns2/. 

HVO is in constant communication with Hawai‘i Volcanoes National Park as this situation evolves. The eruption is currently taking place entirely within the closed area of Hawai‘i Volcanoes National Park. 

HVO is in constant communication with the County of Hawai‘i Civil Defense Agency. 
(12) Volcanic cloud height: None.
(13) Other volcanic cloud information: None.
(14) Remarks: HVO scientists will continue to monitor Kīlauea volcano closely and will issue additional messages as warranted by changing activity. Stay informed about Kīlauea by following volcano updates and tracking current monitoring data on the HVO web page (https://www.usgs.gov/volcanoes/kilauea/volcano-updates) or by signing up to receive updates by email at this site: https://volcanoes.usgs.gov/vns2/.

More Information:
Kīlauea activity summary also available by phone: (808) 967-8862
Kīlauea webcam images: https://www.usgs.gov/volcanoes/kilauea/webcams
Kīlauea photos/video: https://www.usgs.gov/volcanoes/kilauea/photo-video-chronology
Kīlauea lava-flow maps: https://www.usgs.gov/volcanoes/kilauea/maps
Kīlauea FAQs: https://www.usgs.gov/volcanoes/kilauea/faqs

Hazard Analysis: 

This new eruption at Kīlauea’s summit is occurring within a closed area of Hawai'i Volcanoes National Park. Therefore, high levels of volcanic gas are the primary hazard of concern, as this hazard can have far-reaching effects down-wind. Large amounts of volcanic gas—primarily water vapor (H2O), carbon dioxide (CO2), and sulfur dioxide (SO2)—are continuously released during eruptions of Kīlauea Volcano. As SO2 is released from the summit, it will react in the atmosphere to create the visible haze known as vog (volcanic smog) that has been observed downwind of Kīlauea. Vog creates the potential for airborne health hazards to residents and visitors, damages agricultural crops and other plants, and affects livestock. For more information on gas hazards at the summit of Kīlauea, please see: https://pubs.er.usgs.gov/publication/fs20173017. Vog information can be found at https://vog.ivhhn.org/. 



Additional hazards include Pele's hair and other lightweight volcanic glass fragments from the lava fountains that will fall downwind of the fissure vents and dust the ground within a few hundred meters (yards) of the vent (s). Strong winds may waft lighter particles to greater distances. Residents should minimize exposure to these volcanic particles, which can cause skin and eye irritation. 



Other significant hazards also remain around Kīlauea caldera from Halemaʻumaʻu crater wall instability, ground cracking, and rockfalls that can be enhanced by earthquakes within the area closed to the public. This underscores the extremely hazardous nature of Kīlauea caldera rim surrounding Halemaʻumaʻu crater, an area that has been closed to the public since late 2007. 


For discussion of Kīlauea hazards, please see: https://www.usgs.gov/observatories/hawaiian-volcano-observatory/hazards 



Please see the Hawaiʻi Volcanoes National Park website for visitor information: https://www.nps.gov/havo/index.htm. Visitors to Hawai'i Volcanoes National Park should note that under southerly (non-trade) wind conditions, there is potential for a dusting of powdery to gritty ash composed of volcanic glass and rock fragments. These ashfalls represent a minor hazard, but visitors should be aware that dustings of ash at areas around the Kīlauea summit are possible. 
(15) Contacts: askHVO@usgs.gov
(16) Next Notice: The Hawaiian Volcano Observatory (HVO) continues to closely monitor Kīlauea's seismicity, deformation, and gas emissions for any changes in activity. HVO will now issue daily Kīlauea updates until further notice.

Subscribe to these messages:
https://volcanoes.usgs.gov/vns2/

Recent earthquakes in Hawaiʻi (map and list): https://www.usgs.gov/observatories/hawaiian-volcano-observatory/earthquakes

Explanation of Volcano Alert Levels and Aviation Color Codes: https://www.usgs.gov/natural-hazards/volcano-hazards/about-alert-levels
2021-09-30 - Kilauea, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20210930/0109Z)
(3) Volcano: Kilauea (VNUM #332010)
(4) Current Color Code: ORANGE
(5) Previous Color Code: YELLOW
(6) Source: Hawaiian Volcano Observatory
(7) Notice Number: 2021/H261
(8) Volcano Location: N 19 deg 25 min W 155 deg 17 min
(9) Area: Hawaii
(10) Summit Elevation: 4091 ft (1247 m)
(11) Volcanic Activity Summary: Kīlauea volcano is not erupting. Increased earthquake activity and changes in the patterns of ground deformation at Kīlauea’s summit began occurring as of approximately noon on September 29, 2021, indicating movement of magma in the subsurface. At this time, it is not possible to say with certainty if this activity will lead to an eruption -- the activity may remain below ground, as occurred in August 2021 and early December 2020 (two weeks prior to the December 2020 - May 2021 summit eruption), when magma intruded beneath the caldera but did not erupt. However, an eruption in Kilauea’s summit region, within Hawai‘i Volcanoes National Park and away from infrastructure, is one potential outcome.

The US Geological Survey Hawaiian Volcano Observatory is raising the volcano alert level/aviation color code for Kīlauea from Advisory/Yellow to Watch/Orange due to this activity.

HVO will continue to monitor this activity closely and adjust the alert level accordingly.

HVO is in constant communication with Hawai‘i Volcanoes National Park as this situation evolves. The activity is confined entirely within the park.

Stay informed about Kīlauea by following volcano updates and tracking current monitoring data on the HVO web page (https://www.usgs.gov/volcanoes/kilauea/volcano-updates) or by signing up to receive updates by email at this site: https://volcanoes.usgs.gov/vns2/.
(12) Volcanic cloud height: None.
(13) Other volcanic cloud information: None.
(14) Remarks: HVO scientists will continue to monitor Kīlauea volcano closely and will issue additional messages as warranted by changing activity. Stay informed about Kīlauea by following volcano updates and tracking current monitoring data on the HVO web page (https://www.usgs.gov/volcanoes/kilauea/volcano-updates) or by signing up to receive updates by email at this site: https://volcanoes.usgs.gov/vns2/.

More Information:
Kīlauea activity summary also available by phone: (808) 967-8862
Kīlauea webcam images: https://www.usgs.gov/volcanoes/kilauea/webcams
Kīlauea photos/video: https://www.usgs.gov/volcanoes/kilauea/photo-video-chronology
Kīlauea lava-flow maps: https://www.usgs.gov/volcanoes/kilauea/maps
Kīlauea FAQs: https://www.usgs.gov/volcanoes/kilauea/faqs
(15) Contacts: askHVO@usgs.gov
(16) Next Notice: The Hawaiian Volcano Observatory (HVO) continues to closely monitor Kīlauea's seismicity, deformation, and gas emissions for any changes in activity. HVO will now issue weekly Kīlauea updates on Tuesdays until further notice.

Subscribe to these messages:
https://volcanoes.usgs.gov/vns2/

Recent earthquakes in Hawaiʻi (map and list): https://www.usgs.gov/observatories/hawaiian-volcano-observatory/earthquakes

Explanation of Volcano Alert Levels and Aviation Color Codes: https://www.usgs.gov/natural-hazards/volcano-hazards/about-alert-levels
2021-09-24 - Pagan, Aviation Color Code: UNASSIGNED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20210924/2200Z)
(3) Volcano: Pagan (VNUM #284170)
(4) Current Color Code: UNASSIGNED
(5) Previous Color Code: YELLOW
(6) Source: U.S. Geological Survey
(7) Notice Number: 2021/N66
(8) Volcano Location: N 18 deg 7 min E 145 deg 48 min
(9) Area: Northern Mariana Islands
(10) Summit Elevation: 1870 ft (570 m)
(11) Volcanic Activity Summary: No unrest or activity as been observed at Mount Pagan in satellite data since September 6. Thus, the Aviation Color Code and Volcano Alert Level are changed from YELLOW/ADVISORY to UNASSIGNED/UNASSIGNED.

Satellite images showed emissions of volcanic ash and sulfur dioxide gas from September 1-6, 2021. Steaming continues to be observed occasionally in satellite data. Emissions of ash and gas could resume without warning.

Mount Pagan is not monitored with ground-based geophysical instrumentation. We will continue to evaluate satellite imagery, distal geophysical data, and mariner reports when available, but because the volcano is not monitored with ground-based instruments, we cannot provide advanced warning of activity.

Mount Pagan, one of two volcanoes that make up Pagan Island, is located on the northern end of the Island, and is one of the most historically active volcanoes in the Northern Mariana Islands. The last large eruption (VEI 4) of the volcano was in 1981, followed by three and a half decades of intermittent activity. Recent activity prior to 2016 was characterized by vigorous steam plumes and degassing from a shallow magma source.
(12) Volcanic cloud height: None currently observed
(13) Other volcanic cloud information: occasional steaming
(14) Remarks:
(15) Contacts: CNMI Homeland Security and Emergency Management
http://www.cnmihsem.gov.mp/

USGS Northern Mariana Duty Scientist (808) 967-8815
http://volcano.wr.usgs.gov/cnmistatus.php

Satellite information, Washington VAAC
http://www.ssd.noaa.gov/VAAC/washington.html
(16) Next Notice:
2021-09-21 - Semisopochnoi, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20210921/0412Z)
(3) Volcano: Semisopochnoi (VNUM #311060)
(4) Current Color Code: ORANGE
(5) Previous Color Code: RED
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2021/A817
(8) Volcano Location: N 51 deg 55 min E 179 deg 35 min
(9) Area: Aleutians
(10) Summit Elevation: 2625 ft (800 m)
(11) Volcanic Activity Summary: Ash emissions from the ongoing eruption at Semisopochnoi continue at a decreased rate. Over the last few hours, activity has consisted of discrete explosions that occur about once an hour and produce small ash clouds that rise to 10,000 to 15,000 feet above sea level and are currently drifting to the northwest. This represents less significant ash emissions and we are therefore lowering the Aviation Color Code and Volcano Alert Level to ORANGE/WATCH.

Activity at Semisopochnoi remains elevated and ash emissions could increase again at any time.

Please visit the NWS Alaska Aviation Weather Unit for current information about the volcanic ash cloud forecast. https://www.weather.gov/aawu/sigmets
(12) Volcanic cloud height: 10,000 to 15,000 ft. asl
(13) Other volcanic cloud information: Small ash clouds are drifting NW
(14) Remarks: Semisopochnoi is monitored by a local seismic and infrasound network, local web cameras, regional lightning and infrasound sensors, and satellite data.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAF
dfee1@alaska.edu (907) 322-4085

(16) Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at http://www.avo.alaska.edu
2021-09-20 - Semisopochnoi, Aviation Color Code: RED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20210920/1947Z)
(3) Volcano: Semisopochnoi (VNUM #311060)
(4) Current Color Code: RED
(5) Previous Color Code: RED
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2021/A812
(8) Volcano Location: N 51 deg 55 min E 179 deg 35 min
(9) Area: Aleutians
(10) Summit Elevation: 2625 ft (800 m)
(11) Volcanic Activity Summary: Ash emissions from the ongoing eruption at Semisopochnoi continue this morning. Satellite images show an ash cloud up to 10,000 to 15,000 feet above sea level and extending approximately 60 miles (100 km) to the northwest through 19:30 UTC. Explosions were detected throughout the night and into this morning. The Aviation Color Code and Volcano Alert level remain at RED/WARNING.

The Alaska Volcano Observatory will continue to closely monitor all available data and provide updates as available.

Please visit the NWS Alaska Aviation Weather Unit for current information about the volcanic ash cloud forecast. https://www.weather.gov/aawu/sigmets
(12) Volcanic cloud height: 10,000 to 15,000 ft. asl
(13) Other volcanic cloud information: Ash observed in satellite extending 60 miles to the NW
(14) Remarks: Semisopochnoi is monitored by a local seismic and infrasound network, local web cameras, regional lightning and infrasound sensors, and satellite data.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAF
dfee1@alaska.edu (907) 322-4085

(16) Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at http://www.avo.alaska.edu
2021-09-20 - Semisopochnoi, Aviation Color Code: RED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20210920/0558Z)
(3) Volcano: Semisopochnoi (VNUM #311060)
(4) Current Color Code: RED
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2021/A811
(8) Volcano Location: N 51 deg 55 min E 179 deg 35 min
(9) Area: Aleutians
(10) Summit Elevation: 2625 ft (800 m)
(11) Volcanic Activity Summary: Ash emissions from the ongoing eruption at Semisopochnoi have increased in frequency and intensity. Satellite images show an ash cloud at an estimated altitude of 15,000 ft. above sea level extending approximately 60 miles (100 km) to the southeast through 05:00 UTC. Explosions have been observed throughout the day and increased sulfur dioxide gas emissions have been observed in satellite data this afternoon. These observations represent an increase in eruptive activity and Aviation Color Code and Volcano Alert level are being increased to RED/WARNING.

Increasing high clouds over Semisopochnoi will likely obscure satellite views of ash emissions within the hour. Seismic and infrasound monitoring will continue to provide notice of ongoing explosive activity, however it cannot determine the height or extent of ash emissions. The Alaska Volcano Observatory will continue to closely monitor all available data.

Please visit the NWS Alaska Aviation Weather Unit for current information about the volcanic ash cloud forecast. https://www.weather.gov/aawu/sigmets
(12) Volcanic cloud height: 15,000 ft. asl
(13) Other volcanic cloud information: Ash and sulfur dioxide observed in satellite extending 60 miles to the SE
(14) Remarks: Semisopochnoi is monitored by a local seismic and infrasound network, local web cameras, regional lightning and infrasound sensors, and satellite data.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAF
dfee1@alaska.edu (907) 322-4085

(16) Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at http://www.avo.alaska.edu
2021-09-10 - Pagan, Aviation Color Code: YELLOW (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20210910/1815Z)
(3) Volcano: Pagan (VNUM #284170)
(4) Current Color Code: YELLOW
(5) Previous Color Code: ORANGE
(6) Source: U.S. Geological Survey
(7) Notice Number: 2021/N49
(8) Volcano Location: N 18 deg 7 min E 145 deg 48 min
(9) Area: Northern Mariana Islands
(10) Summit Elevation: 1870 ft (570 m)
(11) Volcanic Activity Summary: The eruption of Pagan that began on September 1, 2021, consisting of low-level emissions of volcanic ash and sulfur dioxide gas, has paused or ended. The last observations of ash and sulfur dioxide gas emissions in satellite data was on September 6. Thus, the Aviation Color Code and Volcano Alert Level changed from ORANGE/WATCH to YELLOW/ADVISORY.

Steaming continues to be observed intermittently in satellite data. It is unclear whether the eruption has paused or ended. Emissions of ash and gas could resume without warning.

Mount Pagan is not monitored with ground-based geophysical instrumentation. We will continue to evaluate satellite imagery, distal geophysical data, and mariner reports when available, but because the volcano is not monitored with ground-based instruments, we cannot provide advanced warning of activity.

Mount Pagan, one of two volcanoes that make up Pagan Island, is located on the northern end of the Island, and is one of the most historically active volcanoes in the Northern Mariana Islands. The last large eruption (VEI 4) of the volcano was in 1981, followed by three and a half decades of intermittent activity. Recent activity prior to 2016 was characterized by vigorous steam plumes and degassing from a shallow magma source.
(12) Volcanic cloud height: None currently observed
(13) Other volcanic cloud information: Intermittent steaming
(14) Remarks:
(15) Contacts: CNMI Homeland Security and Emergency Management
http://www.cnmihsem.gov.mp/

USGS Northern Mariana Duty Scientist (808) 967-8815
http://volcano.wr.usgs.gov/cnmistatus.php

Satellite information, Washington VAAC
http://www.ssd.noaa.gov/VAAC/washington.html
(16) Next Notice:
2021-09-01 - Pagan, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20210901/1844Z)
(3) Volcano: Pagan (VNUM #284170)
(4) Current Color Code: ORANGE
(5) Previous Color Code: YELLOW
(6) Source: U.S. Geological Survey
(7) Notice Number: 2021/N40
(8) Volcano Location: N 18 deg 7 min E 145 deg 48 min
(9) Area: Northern Mariana Islands
(10) Summit Elevation: 1870 ft (570 m)
(11) Volcanic Activity Summary: Low-level volcanic gas and ash emissions from Pagan Volcano have been observed in satellite data from September 1. A continuous plume from the summit extended up to 150 km (93 miles) to the northwest and southwest of the volcano at an altitude of 10,000 ft above sea level for most of the day. Emissions ceased at 13:00 UTC September 1 (11:00 PM local time) but may resume with little warning. The Aviation Color Code/Volcano Alert Level for Mount Pagan is being changed to ORANGE/WATCH.

Mount Pagan is not monitored with ground-based geophysical instrumentation. We will continue to evaluate satellite imagery, distal geophysical data, and mariner reports when available, but because the volcano is not monitored with ground-based instruments, we cannot provide advanced warning of activity.

Mount Pagan, one of two volcanoes that make up Pagan Island, is located on the northern end of the Island, and is one of the most historically active volcanoes in the Northern Mariana Islands. The last large eruption (VEI 4) of the volcano was in 1981, followed by three and a half decades of intermittent activity. Recent activity prior to 2016 was characterized by vigorous steam plumes and degassing from a shallow magma source.
(12) Volcanic cloud height: 10,000 ft
(13) Other volcanic cloud information: n/a
(14) Remarks:
(15) Contacts: CNMI Homeland Security and Emergency Management
http://www.cnmihsem.gov.mp/

USGS Northern Mariana Duty Scientist (808) 967-8815
http://volcano.wr.usgs.gov/cnmistatus.php

Satellite information, Washington VAAC
http://www.ssd.noaa.gov/VAAC/washington.html
(16) Next Notice:
2021-08-27 - Atka volcanic complex, Aviation Color Code: GREEN (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20210827/1724Z)
(3) Volcano: Atka volcanic complex (VNUM #311160)
(4) Current Color Code: GREEN
(5) Previous Color Code: YELLOW
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2021/A710
(8) Volcano Location: N 52 deg 19 min W 174 deg 8 min
(9) Area: Aleutians
(10) Summit Elevation: 5030 ft (1533 m)
(11) Volcanic Activity Summary: The Alaska Volcano Observatory is lowering the Aviation Color Code and Alert Level at the Atka volcanic complex to GREEN/NORMAL. On August 10, AVO detected an increase in small earthquakes, located between 6 and 2 km (4 and 1 miles) below sea level, about 5 km (3 miles) west of Kliuchef volcano within the Atka volcanic complex.. After several days of increased seismicity, the earthquake rate began to drop, and has subsequently returned to background levels.

Previous alerts by the Alaska Volcano Observatory for unrest at the Atka volcanic complex have been for Korovin Volcano, the site of the most recent historical eruptions. The location of earthquakes, however, is not specific to Korovin and could be related to several other volcanic vents that are part of the Atka volcanic complex, including Mount Kliuchef.

The Alaska Volcano Observatory will continue to monitor the Atka volcanic complex for signs of volcanic activity. The area is monitored by local seismic and infrasound sensors, satellite data, and regional lightning detection instruments.
(12) Volcanic cloud height: n/a
(13) Other volcanic cloud information: n/a
(14) Remarks:
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS mcoombs@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAF dfee1@alaska.edu (907) 322-4085
(16) Next Notice:
2021-08-26 - Kilauea, Aviation Color Code: YELLOW (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20210826/1944Z)
(3) Volcano: Kilauea (VNUM #332010)
(4) Current Color Code: YELLOW
(5) Previous Color Code: ORANGE
(6) Source: Hawaiian Volcano Observatory
(7) Notice Number: 2021/H241
(8) Volcano Location: N 19 deg 25 min W 155 deg 17 min
(9) Area: Hawaii
(10) Summit Elevation: 4091 ft (1247 m)
(11) Volcanic Activity Summary: Kīlauea volcano is not erupting. Over the past 24 hours, earthquake activity and ground deformation levels have decreased in the area beneath the southern part of Kīlauea’s summit caldera within the closed area of Hawaiʻi Volcanoes National Park. These observations indicate that the immediate potential for an eruption is diminished at this time.

The U.S. Geological Survey’s Hawaiian Volcano Observatory is lowering the Volcano Alert Level/Aviation Color Code for Kīlauea from WATCH/ORANGE to ADVISORY/YELLOW reflecting this decrease in activity levels.
(12) Volcanic cloud height: None.
(13) Other volcanic cloud information: None.
(14) Remarks: The earthquake swarm that began beneath the south part of Kīlauea caldera, within Hawaiʻi Volcanoes National Park, on August 23, 2021, has waned. Within the past 24 hours, only 10 earthquakes have been detected in this area. The earthquake swarm began in that region at around 4:30 p.m. HST on August 23 and continued until the morning of August 25, 2021. 478 earthquakes were detected during this swarm; the rate of earthquakes detected per hour peaked at 28 events between 7 and 8 p.m. HST on August 24. Most of the earthquakes were between magnitude 1 and 2 and occurred approximately 1-2 km (0.6-1.2 mi) below the Earth’s surface.

The earthquake swarm was accompanied by change in the rate and style of ground deformation. Ground deformation in the Kīlauea summit region has leveled off within the past 24 hours and rapid inflation near the region of Kīlauea’s south caldera is no longer being observed.

Earthquake activity and ground deformation have decreased together to levels that indicate magma is no longer moving into the region of Kīlauea’s south caldera. These changes indicate reduced potential for an eruption at this time.

Kīlauea summit sulfur dioxide (SO2) emission rates remain at very low levels that have persisted since May 2021, when the most recent summit eruption ended. Concentrations of SO2 in ambient air, measured at stations in the Kīlauea summit region, show no changes. The most recent SO2 emission rates, measured on August 12, were 50 tonnes per day, close to levels associated with the non-eruptive period from late 2018 to late 2020 (less than 50 tonnes per day). This is significantly lower than emission rates that averaged over 800 tonnes per day from mid-February to mid-April when the summit eruption of Kīlauea was ongoing.

HVO scientists will continue to monitor Kīlauea volcano closely and will issue additional messages as warranted by changing activity. Stay informed about Kīlauea by following volcano updates and tracking current monitoring data on the HVO web page (https://www.usgs.gov/volcanoes/kilauea/volcano-updates) or by signing up to receive updates by email at this site: https://volcanoes.usgs.gov/vns2/.

More Information:
Kīlauea activity summary also available by phone: (808) 967-8862
Kīlauea webcam images: https://www.usgs.gov/volcanoes/kilauea/webcams
Kīlauea photos/video: https://www.usgs.gov/volcanoes/kilauea/photo-video-chronology
Kīlauea lava-flow maps: https://www.usgs.gov/volcanoes/kilauea/maps
Kīlauea FAQs: https://www.usgs.gov/volcanoes/kilauea/faqs
(15) Contacts: askHVO@usgs.gov
(16) Next Notice: The Hawaiian Volcano Observatory (HVO) continues to closely monitor Kīlauea's seismicity, deformation, and gas emissions for any changes in activity. HVO will now issue weekly Kīlauea updates on Tuesdays until further notice.

Subscribe to these messages:
https://volcanoes.usgs.gov/vns2/

Recent earthquakes in Hawaiʻi (map and list): https://www.usgs.gov/observatories/hawaiian-volcano-observatory/earthquakes

Explanation of Volcano Alert Levels and Aviation Color Codes: https://www.usgs.gov/natural-hazards/volcano-hazards/about-alert-levels
2021-08-24 - Kilauea, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20210824/1534Z)
(3) Volcano: Kilauea (VNUM #332010)
(4) Current Color Code: ORANGE
(5) Previous Color Code: YELLOW
(6) Source: Hawaiian Volcano Observatory
(7) Notice Number: 2021/H238
(8) Volcano Location: N 19 deg 25 min W 155 deg 17 min
(9) Area: Hawaii
(10) Summit Elevation: 4091 ft (1247 m)
(11) Volcanic Activity Summary: Kīlauea volcano is not erupting. A swarm of earthquakes beneath the south part of Kīlauea caldera, within Hawaiʻi Volcanoes National Park, began on the evening of August 23, 2021. The swarm continues into the early morning hours of August 24 with a particularly strong sequence of earthquakes that occurred at about 1:30 a.m., HST. The onset of the earthquake swarm was coincident with a change in the style of ground deformation at tiltmeters in the Kīlauea summit region, potentially indicating the shallow movement of magma beneath the south part of Kīlauea caldera.

The US Geological Survey Hawaiian Volcano Observatory is raising the volcano alert level/aviation color code for Kīlauea from Advisory/Yellow to Watch/Orange due to this activity.

HVO will continue to monitor this activity closely and adjust the alert level accordingly.

HVO is in constant communication with Hawai‘i Volcanoes National Park as this situation evolves. The activity is confined entirely within the park.

Stay informed about Kīlauea by following volcano updates and tracking current monitoring data on the HVO web page (https://www.usgs.gov/volcanoes/kilauea/volcano-updates) or by signing up to receive updates by email at this site: https://volcanoes.usgs.gov/vns2/.
(12) Volcanic cloud height: None.
(13) Other volcanic cloud information: None.
(14) Remarks: The US Geological Survey Hawaiian Volcano Observatory has detected an increase in earthquake activity beneath the south part of Kīlauea summit caldera, within Hawaiʻi Volcanoes National Park. The activity began around 4:30 p.m., HST, on August 23 and continued through the night and into the early morning of August 24, 2021. The swarm was accompanied by an increase in the style of ground deformation recorded by the Sandhill tiltmeter, just to the west of the earthquake swarm location. The same tilt increase was also recorded by the tiltmeter near Uēkahuna Bluff and the site of the old HVO building.

At about 1:30 a.m. this morning, the swarm of earthquakes intensified in this region; this activity may indicate an intrusion of magma occurring 1–2 km (0.6–1.2 miles) beneath the south caldera.

Over 140 earthquakes have been recorded as of 4:30 a.m. on August 24; the largest recorded earthquake was magnitude 3.3 with the majority of earthquakes less than magnitude 1. Small earthquakes are continuing at a rate of at least 10 detected earthquakes per hour.

Currently, webcams and satellite imagery show no evidence of lava at the surface. HVO scientists will continue the monitor the situation and will issue additional messages and alert level changes as warranted by changing activity.

For discussion of Kīlauea hazards, please see:

https://www.usgs.gov/observatories/hawaiian-volcano-observatory/hazards

More Information:
Kīlauea activity summary also available by phone: (808) 967-8862
Kīlauea webcam images: https://www.usgs.gov/volcanoes/kilauea/webcams
Kīlauea photos/video: https://www.usgs.gov/volcanoes/kilauea/photo-video-chronology
Kīlauea lava-flow maps: https://www.usgs.gov/volcanoes/kilauea/maps
Kīlauea FAQs: https://www.usgs.gov/volcanoes/kilauea/faqs
(15) Contacts: askHVO@usgs.gov
(16) Next Notice: The Hawaiian Volcano Observatory (HVO) continues to closely monitor Kīlauea's seismicity, deformation, and gas emissions for any changes in activity. HVO will now issue daily Kīlauea updates until further notice.

Subscribe to these messages:
https://volcanoes.usgs.gov/vns2/

Recent earthquakes in Hawaiʻi (map and list): https://www.usgs.gov/observatories/hawaiian-volcano-observatory/earthquakes

Explanation of Volcano Alert Levels and Aviation Color Codes: https://www.usgs.gov/natural-hazards/volcano-hazards/about-alert-levels
2021-08-11 - Atka volcanic complex, Aviation Color Code: YELLOW (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20210811/2222Z)
(3) Volcano: Atka Volcanic Complex (VNUM #311160)
(4) Current Color Code: YELLOW
(5) Previous Color Code:
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2021/A629
(8) Volcano Location: N 52 deg 19 min W 174 deg 8 min
(9) Area: Aleutians
(10) Summit Elevation: 5030 ft (1533 m)
(11) Volcanic Activity Summary: The Alaska Volcano Observatory is raising the Aviation Color Code and Alert Level at the Atka volcanic complex to YELLOW/ADVISORY after detecting an increased number of small, shallow earthquakes over the past day. These earthquakes have been located 3 to 6 km (1.9 to 3.7 miles) deep and around 7 km (4.3 miles) southwest of Korovin Volcano. The earthquakes represent an increase from background seismic activity, but may not necessarily lead to an eruption.

Previous alerts by the Alaska Volcano Observatory for unrest for the Atka volcanic complex have been for Korovin Volcano, the site of the most recent historical eruptions. The location of earthquakes, however, is not specific to Korovin and could be related to several other volcanic vents that are part of the Atka volcanic complex, including Mount Kliuchef.

The Alaska Volcano Observatory will continue to monitor the Atka volcanic complex for signs of volcanic activity. The area is monitored by local seismic and infrasound sensors, satellite data, and regional lightning detection instruments.
(12) Volcanic cloud height: n/a
(13) Other volcanic cloud information: n/a
(14) Remarks:
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS mcoombs@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAF dfee1@alaska.edu (907) 322-4085
(16) Next Notice:
2021-08-05 - Pavlof, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20210805/1755Z)
(3) Volcano: Pavlof (VNUM #312030)
(4) Current Color Code: ORANGE
(5) Previous Color Code: YELLOW
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2021/A604
(8) Volcano Location: N 55 deg 25 min W 161 deg 53 min
(9) Area: Alaska Peninsula
(10) Summit Elevation: 8261 ft (2518 m)
(11) Volcanic Activity Summary: Clear web camera views of Pavlof Volcano this morning indicate episodic low-level ash emissions are occurring. Intermittent bursts of ash from the summit are producing diffuse ash clouds that are rising just above the summit (summit elevation 8261 ft above sea level) and drifting southeast roughly 6 mi before dissipating. Seismic and infrasound data indicate that activity consists of occasional small explosions and tremor. The ash emissions indicate an active eruption in progress thus the Alaska Volcano Observatory is raising the Aviation Color Code and Alert Level to ORANGE/WATCH.
(12) Volcanic cloud height: None
(13) Other volcanic cloud information: None
(14) Remarks: Pavlof Volcano is a snow- and ice-covered stratovolcano located on the southwestern end of the Alaska Peninsula about 953 km (592 mi) southwest of Anchorage. The volcano is about 7 km (4.4 mi) in diameter and has active vents on the north and east sides close to the summit. With over 40 historic eruptions, it is one of the most consistently active volcanoes in the Aleutian arc. Eruptive activity is generally characterized by sporadic Strombolian lava fountaining continuing for a several-month period. Ash plumes as high as 49,000 ft ASL have been generated by past eruptions of Pavlof, and during the March 2016 eruption, ash plumes as high as 40,000 feet above sea level were generated and the ash was tracked in satellite data as distant as eastern Canada. The nearest community, Cold Bay, is located 60 km (37 miles) to the southwest of Pavlof.
(15) Contacts: Matt Haney, Acting Scientist-in-Charge, USGS mhaney@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAF dfee1@alaska.edu (907) 322-4085
(16) Next Notice:
2021-07-31 - Semisopochnoi, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20210731/1819Z)
(3) Volcano: Semisopochnoi (VNUM #311060)
(4) Current Color Code: ORANGE
(5) Previous Color Code: YELLOW
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2021/A592
(8) Volcano Location: N 51 deg 55 min E 179 deg 35 min
(9) Area: Aleutians
(10) Summit Elevation: 2625 ft (800 m)
(11) Volcanic Activity Summary: Seismic activity at Semisopochnoi has increased in recent days with a marked increase in the past 8 hours. Increased activity has also been detected on local infrasound stations, suggesting possible low-level (below 10,000 ft above sea level) emissions. Due to this increase in activity, AVO is raising the Aviation Color Code to ORANGE and the Alert Level to WATCH.

When occurring, small eruptions producing minor ash deposits within the vicinity of the active north crater of Mount Cerberus and ash clouds under 10,000 ft above sea level are typical of activity at Semisopochnoi.
(12) Volcanic cloud height: none
(13) Other volcanic cloud information: none
(14) Remarks: Semisopochnoi is monitored by a local seismic and infrasound network, local web cameras, regional lightning and infrasound sensors, and satellite data.
(15) Contacts: Matt Haney, Acting Scientist-in-Charge, USGS mhaney@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAF dfee1@alaska.edu (907) 322-4085
(16) Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at http://www.avo.alaska.edu
2021-07-29 - Pagan, Aviation Color Code: YELLOW (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20210729/0912Z)
(3) Volcano: Pagan (VNUM #284170)
(4) Current Color Code: YELLOW
(5) Previous Color Code: UNASSIGNED
(6) Source: U.S. Geological Survey
(7) Notice Number: 2021/N31
(8) Volcano Location: N 18 deg 7 min E 145 deg 48 min
(9) Area: Northern Mariana Islands
(10) Summit Elevation: 1870 ft (570 m)
(11) Volcanic Activity Summary: Ground-based observations from local residents indicate that there were felt earthquakes and a light emission from Mount Pagan at approximately 4:30 UTC July 29 (2:30pm local time July 28). This represents a departure from background activity and therefore the Aviation Color Code/Volcano Alert Status for Mount Pagan is being changed to YELLOW/ADVISORY.

Mount Pagan is not monitored with ground-based geophysical instrumentation. Furthermore, no indications of the current unrest have been detected in satellite or distal seismic data. We will continue to evaluate satellite imagery, distal geophysical data, on-island, and mariner reports when available, but because the volcano is not monitored with ground-based instruments, we cannot provide advanced warning of activity.

Mount Pagan, one of two volcanoes that make up Pagan Island, is located on the northern end of the Island, and is one of the most historically active volcanoes in the Northern Mariana Islands. The last large eruption (VEI 4) of the volcano was in 1981, followed by three and a half decades of intermittent activity. Recent activity prior to 2016 was characterized by vigorous steam plumes and degassing from a shallow magma source.
(12) Volcanic cloud height: Unknown
(13) Other volcanic cloud information: Unknown
(14) Remarks:
(15) Contacts: CNMI Homeland Security and Emergency Management
http://www.cnmihsem.gov.mp/

USGS Northern Mariana Duty Scientist (808) 967-8815
http://volcano.wr.usgs.gov/cnmistatus.php

Satellite information, Washington VAAC
http://www.ssd.noaa.gov/VAAC/washington.html
(16) Next Notice:
2021-07-28 - Gareloi, Aviation Color Code: GREEN (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20210728/1933Z)
(3) Volcano: Gareloi (VNUM #311070)
(4) Current Color Code: GREEN
(5) Previous Color Code: YELLOW
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2021/A569
(8) Volcano Location: N 51 deg 47 min W 178 deg 47 min
(9) Area: Aleutians
(10) Summit Elevation: 5161 ft (1573 m)
(11) Volcanic Activity Summary: The increase in seismic activity observed in May and June, 2021 at Mount Gareloi (Gareloi volcano) has diminished. Because the level of seismic activity is now at background, AVO is returning the aviation color code to GREEN and the Volcano Alert Level to NORMAL.

Gareloi is monitored by a local seismic and infrasound network, satellite data, and regional infrasound and lightning-detection networks.
(12) Volcanic cloud height: None
(13) Other volcanic cloud information: n/a
(14) Remarks: Mount Gareloi, which makes up all of Gareloi Island, is a stratovolcano located in the Delarof Islands group of the Aleutian Islands, about 2,000 km (1,242 mi) west-southwest of Anchorage and about 150 km (93 mi) west of Adak, the westernmost community in Alaska. This small volcano is 10 × 8 km (6.2 × 5.0 mi) in diameter at its base with two summits, separated by a narrow saddle. The northern, slightly higher peak contains crater about 300 m (1,000 ft) across. The southern summit has a crater open to the south and a persistent degassing vent (fumarole) on its western rim. Gareloi has been one of the most active in the Aleutians since the 1740s, with 16 reports of eruptive activity at Gareloi since 1760. In 1929, its largest historical eruption produced sixteen small south- to southeast-trending craters that extend from the southern summit to the coast, as well as lava flows and pyroclastic deposits on the southeastern flank of the volcano. Eruptions of Gareloi commonly produce ash clouds and lava flows, and the primary hazard is airborne clouds of ash that could affect aircraft. Since seismic instruments were installed in 2003, they have detected small but consistent seismic signals from beneath Mount Gareloi’s edifice.
(15) Contacts: Matt Haney, Acting Scientist-in-Charge, USGS mhaney@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAF dfee1@alaska.edu (907) 322-4085
(16) Next Notice:
2021-07-23 - Great Sitkin, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20210723/2225Z)
(3) Volcano: Great Sitkin (VNUM #311120)
(4) Current Color Code: ORANGE
(5) Previous Color Code: YELLOW
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2021/A553
(8) Volcano Location: N 52 deg 4 min W 176 deg 6 min
(9) Area: Aleutians
(10) Summit Elevation: 5709 ft (1740 m)
(11) Volcanic Activity Summary: A satellite radar image from last night July 22, 9:32 PM local (July 23 05:32 UTC) shows a small ~50 m (~150 ft) diameter area of uplift in the center of the crater at Great Sitkin suggestive of rising magma near the surface. This lava dome-like feature appears to have been emplaced sometime between July 14 and 22. As a result AVO is raising the the Aviation Color Code to ORANGE and the Volcano Alert Level to WATCH. Seismicity has been at relatively low levels this week compared to last week and we suspect that the lava dome-like feature was emplaced last week. Moderately elevated surface temperatures consistent with this feature were observed in satellite data on July 22. Cloudy conditions have obscured views of the volcano by satellite most of the past week. AVO will continue to closely monitor this new uplift feature.

The prognosis for eruptive activity is uncertain. Continued growth of the lava dome feature, additional explosive events, or a return to non-eruptive behaviors are all possible. AVO will report on significant changes and observations in monitoring data should they occur.

Great Sitkin is monitored with a local real-time seismic network, which will typically allow AVO to detect changes in unrest that may lead to an explosive eruption. Rapid detection of an ash-producing eruption would be accomplished using a combination of seismic, infrasound, lightning, and satellite data.
(12) Volcanic cloud height: None
(13) Other volcanic cloud information: n/a
(14) Remarks: Great Sitkin Volcano is a basaltic andesite volcano that occupies most of the northern half of Great Sitkin Island, a member of the Andreanof Islands group in the central Aleutian Islands. It is located 43 km (26 miles) east of the community of Adak. The volcano is a composite structure consisting of an older dissected volcano and a younger parasitic cone with a 3-km-diameter summit crater. A steep-sided lava dome, emplaced during an eruption in 1974, occupies the center of the crater. Great Sitkin erupted at least three times in the 20th century, most recently in 1974. That eruption produced at least one ash cloud that likely exceeded an altitude of 25,000 ft above sea level. A poorly documented eruption occurred in 1945, also producing a lava dome that was partially destroyed in the 1974 eruption. Within the past 280 years a large explosive eruption produced pyroclastic flows that partially filled the Glacier Creek valley on the southwest flank.
(15) Contacts: Matt Haney, Acting Scientist-in-Charge, USGS mhaney@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAF dfee1@alaska.edu (907) 322-4085
(16) Next Notice:
2021-07-22 - Semisopochnoi, Aviation Color Code: YELLOW (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20210722/0028Z)
(3) Volcano: Semisopochnoi (VNUM #311060)
(4) Current Color Code: YELLOW
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2021/A542
(8) Volcano Location: N 51 deg 55 min E 179 deg 35 min
(9) Area: Aleutians
(10) Summit Elevation: 2625 ft (800 m)
(11) Volcanic Activity Summary: Due to a marked decline is seismicity and no evidence of explosive activity detected in satellite, seismic or infrasound data since July 12, AVO is decreasing the Aviation Color Code to YELLOW and the Alert Level to ADVISORY.

When occurring, small eruptions producing minor ash deposits within the vicinity of the active north crater of Mount Cerberus and ash clouds under 10,000 ft above sea level are typical of activity at Semisopochnoi.
(12) Volcanic cloud height: none
(13) Other volcanic cloud information: none
(14) Remarks: Semisopochnoi is monitored by a local seismic and infrasound network, local web cameras, regional lightning and infrasound sensors, and satellite data.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS mcoombs@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAF dfee1@alaska.edu (907) 322-4085
(16) Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at http://www.avo.alaska.edu
2021-07-13 - Semisopochnoi, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20210713/0014Z)
(3) Volcano: Semisopochnoi (VNUM #311060)
(4) Current Color Code: ORANGE
(5) Previous Color Code: YELLOW
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2021/A490
(8) Volcano Location: N 51 deg 55 min E 179 deg 35 min
(9) Area: Aleutians
(10) Summit Elevation: 2625 ft (800 m)
(11) Volcanic Activity Summary: Continuous volcanic tremor (constant shaking) began to be observed at ~2000 UTC (12 pm AKDT) and continues through the present time. Ash emissions were visible in satellite data beginning around 2100 UTC (1 pm AKDT) to an altitude of less than 5,000 feet asl (based on wind direction). Satellite observations from yesterday afternoon showed a robust steam plume and sulfur dioxide gas emissions. These observations indicate an increase in unrest and the Aviation Color Code is being increased to ORANGE, and the Volcano Alert Level is being increased to WATCH. Additional ash emissions are probable, but not certain.

When occurring, small eruptions producing minor ash deposits within the vicinity of the active north crater of Mount Cerberus and ash clouds under 10,000 ft above sea level are typical of activity at Semisopochnoi.
(12) Volcanic cloud height: Less than 5,000 ft asl.
(13) Other volcanic cloud information: Observed in GOES-17 satellite
(14) Remarks: Semisopochnoi is monitored by a local seismic and infrasound network, regional lightning and infrasound sensors, and satellite data.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS mcoombs@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAF dfee1@alaska.edu (907) 322-4085
(16) Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at http://www.avo.alaska.edu
2021-07-09 - Pavlof, Aviation Color Code: YELLOW (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20210709/1940Z)
(3) Volcano: Pavlof (VNUM #312030)
(4) Current Color Code: YELLOW
(5) Previous Color Code: GREEN
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2021/A468
(8) Volcano Location: N 55 deg 25 min W 161 deg 53 min
(9) Area: Alaska Peninsula
(10) Summit Elevation: 8261 ft (2518 m)
(11) Volcanic Activity Summary: Seismic activity has increased at Pavlof Volcano over the past 16 hours and is characterized by tremor. No eruptive activity or emissions from the summit have been observed. The seismic activity represents an increase from background levels therefore the Alaska Volcano Observatory is raising the Aviation Color Code and Alert Level to YELLOW/ADVISORY. This does not mean that an eruption is likely or imminent. However, past eruptions of Pavlof occurred with little or no warning.
(12) Volcanic cloud height: None
(13) Other volcanic cloud information: None
(14) Remarks: Pavlof Volcano is a snow- and ice-covered stratovolcano located on the southwestern end of the Alaska Peninsula about 953 km (592 mi) southwest of Anchorage. The volcano is about 7 km (4.4 mi) in diameter and has active vents on the north and east sides close to the summit. With over 40 historic eruptions, it is one of the most consistently active volcanoes in the Aleutian arc. Eruptive activity is generally characterized by sporadic Strombolian lava fountaining continuing for a several-month period. Ash plumes as high as 49,000 ft ASL have been generated by past eruptions of Pavlof, and during the March 2016 eruption, ash plumes as high as 40,000 feet above sea level were generated and the ash was tracked in satellite data as distant as eastern Canada. The nearest community, Cold Bay, is located 60 km (37 miles) to the southwest of Pavlof.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS mcoombs@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAF dfee1@alaska.edu (907) 322-4085
(16) Next Notice:
2021-07-08 - Veniaminof, Aviation Color Code: GREEN (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20210708/1838Z)
(3) Volcano: Veniaminof (VNUM #312070)
(4) Current Color Code: GREEN
(5) Previous Color Code: UNASSIGNED
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2021/A463
(8) Volcano Location: N 56 deg 11 min W 159 deg 23 min
(9) Area: Alaska Peninsula
(10) Summit Elevation: 8225 ft (2507 m)
(11) Volcanic Activity Summary: The Alaska Volcano Observatory is moving the status of Veniaminof Volcano from UNASSIGNED/UNASSIGNED to GREEN/NORMAL. Recent field operations were successful in restoring seismic stations on Veniaminof allowing AVO to resume monitoring potential activity at the volcano.
(12) Volcanic cloud height: n/a
(13) Other volcanic cloud information: n/a
(14) Remarks: Mount Veniaminof volcano is an andesitic stratovolcano with an ice-filled 10-km diameter summit caldera located on the Alaska Peninsula, 775 km (480 mi) southwest of Anchorage and 35 km (22 mi) north of Perryville. Veniaminof is one of the largest (~300 cubic km; 77 cubic mi) and most active volcanic centers in the Aleutian Arc and has erupted at least 14 times in the past 200 years. Recent eruptions in 1993-95, 2005, 2013, and 2018 all occurred at the intracaldera cone and lasted for several months. These eruptions produced lava spattering and fountaining, minor emissions of ash and gas, and small lava flows into intracaldera icefield. Minor ash-producing explosions occurred nearly annually between 2002 and 2010. Previous historical eruptions have produced ash plumes that reached 15,000 to 20,000 ft above sea level (1939, 1956, and 2018) and ash fallout that blanketed areas within about 40 km (25 mi) of the volcano (1939, 2018).
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS mcoombs@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAF dfee1@alaska.edu (907) 322-4085
(16) Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at
http://www.avo.alaska.edu
2021-06-16 - Semisopochnoi, Aviation Color Code: YELLOW (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20210616/2159Z)
(3) Volcano: Semisopochnoi (VNUM #311060)
(4) Current Color Code: YELLOW
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2021/A374
(8) Volcano Location: N 51 deg 55 min E 179 deg 35 min
(9) Area: Aleutians
(10) Summit Elevation: 2625 ft (800 m)
(11) Volcanic Activity Summary: No ash emissions or explosions from Semisopochnoi have been detected in satellite or infrasound data since May 30, and the level of seismic activity has been relatively low. Satellite views over the past few weeks have detected elevated surface temperatures, and sulfur dioxide emissions were observed on several occasions, indicating continued volcanic unrest, but no recent ash deposits have been observed. Because of the low level of seismicity and lack of significant explosive activity, AVO is lowering the Aviation Color Code and Volcano Alert Level to YELLOW/ADVISORY.

When occurring, small eruptions producing minor ash deposits within the vicinity of the active north crater of Mount Cerberus and ash clouds under 10,000 ft above sea level are typical of activity at Semisopochnoi.
(12) Volcanic cloud height: Unknown
(13) Other volcanic cloud information: Unknown
(14) Remarks: Semisopochnoi is monitored by a local seismic and infrasound network, regional lightning and infrasound sensors, and satellite data.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS mcoombs@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAF dfee1@alaska.edu (907) 322-4085
(16) Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at http://www.avo.alaska.edu
2021-06-08 - Gareloi, Aviation Color Code: YELLOW (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20210608/1743Z)
(3) Volcano: Gareloi (VNUM #311070)
(4) Current Color Code: YELLOW
(5) Previous Color Code: GREEN
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2021/A338
(8) Volcano Location: N 51 deg 47 min W 178 deg 47 min
(9) Area: Aleutians
(10) Summit Elevation: 5161 ft (1573 m)
(11) Volcanic Activity Summary: A slight increase in seismic activity was observed at Mount Gareloi (Gareloi volcano) on May 18, and beginning May 27 there has been a sustained increase in the rate and size of small volcanic earthquakes. Because the level of seismic activity is now above background, AVO is raising the aviation color code to YELLOW and the Volcano Alert Level to ADVISORY. There have been no other notable changes at the volcano in satellite data or web camera views. Sulfur dioxide gas was detected in satellite imagery from Gareloi over the past week and is consistent with measurements from the last several years. No activity was observed by an AVO field crew flying over the summit on May 23.

Gareloi volcano persistently emits magmatic gases from a fumarole field on the south crater and commonly exhibits low-level seismic activity. These observations suggest the presence of shallow magma and potential interaction with a hydrothermal system. The current increase in seismicity likely reflects a change to the magmatic-hydrothermal system, but it is not clear that the likelihood of a volcanic eruption has increased. AVO will continue to monitor activity to determine if the recent changes are related to influx of new magma or other changes to the magma system.

Gareloi is monitored by a local seismic and infrasound network, satellite data, and regional infrasound and lightning-detection networks.
(12) Volcanic cloud height: None
(13) Other volcanic cloud information: n/a
(14) Remarks: Mount Gareloi, which makes up all of Gareloi Island, is a stratovolcano located in the Delarof Islands group of the Aleutian Islands, about 2,000 km (1,242 mi) west-southwest of Anchorage and about 150 km (93 mi) west of Adak, the westernmost community in Alaska. This small volcano is 10 × 8 km (6.2 × 5.0 mi) in diameter at its base with two summits, separated by a narrow saddle. The northern, slightly higher peak contains crater about 300 m (1,000 ft) across. The southern summit has a crater open to the south and a persistent degassing vent (fumarole) on its western rim. Gareloi has been one of the most active in the Aleutians since the 1740s, with 16 reports of eruptive activity at Gareloi since 1760. In 1929, its largest historical eruption produced sixteen small south- to southeast-trending craters that extend from the southern summit to the coast, as well as lava flows and pyroclastic deposits on the southeastern flank of the volcano. Eruptions of Gareloi commonly produce ash clouds and lava flows, and the primary hazard is airborne clouds of ash that could affect aircraft. Since seismic instruments were installed in 2003, they have detected small but consistent seismic signals from beneath Mount Gareloi’s edifice.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS mcoombs@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAF dfee1@alaska.edu (907) 322-4085
(16) Next Notice:
2021-05-27 - Great Sitkin, Aviation Color Code: YELLOW (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20210527/2058Z)
(3) Volcano: Great Sitkin (VNUM #311120)
(4) Current Color Code: YELLOW
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2021/A307
(8) Volcano Location: N 52 deg 4 min W 176 deg 6 min
(9) Area: Aleutians
(10) Summit Elevation: 5709 ft (1740 m)
(11) Volcanic Activity Summary: Seismicity has remained at low levels following the explosive event on May 25 (local time). Satellite observations showed very minor steaming and slightly elevated surface temperatures during breaks in the cloud cover yesterday afternoon. Thus, the Aviation Color Code is being decreased to YELLOW and the Volcano Alert Level to ADVISORY.

The prognosis for renewed eruptive activity is uncertain. Additional explosive events, the eruption of lava, or a return to non-eruptive behaviors are all possible. AVO will report on significant changes and observations in monitoring data should they occur.

Great Sitkin is monitored with a local real-time seismic network, which will typically allow AVO to detect changes in unrest that may lead to an explosive eruption. Rapid detection of an ash-producing eruption would be accomplished using a combination of seismic, infrasound, lightning, and satellite data.
(12) Volcanic cloud height: None
(13) Other volcanic cloud information: n/a
(14) Remarks: Great Sitkin Volcano is a basaltic andesite volcano that occupies most of the northern half of Great Sitkin Island, a member of the Andreanof Islands group in the central Aleutian Islands. It is located 43 km (26 miles) east of the community of Adak. The volcano is a composite structure consisting of an older dissected volcano and a younger parasitic cone with a 3-km-diameter summit crater. A steep-sided lava dome, emplaced during an eruption in 1974, occupies the center of the crater. Great Sitkin erupted at least three times in the 20th century, most recently in 1974. That eruption produced at least one ash cloud that likely exceeded an altitude of 25,000 ft above sea level. A poorly documented eruption occurred in 1945, also producing a lava dome that was partially destroyed in the 1974 eruption. Within the past 280 years a large explosive eruption produced pyroclastic flows that partially filled the Glacier Creek valley on the southwest flank.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAF
dfee1@alaska.edu (907) 322-4085
(16) Next Notice:
2021-05-27 - Gareloi, Aviation Color Code: GREEN (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20210527/2013Z)
(3) Volcano: Gareloi (VNUM #311070)
(4) Current Color Code: GREEN
(5) Previous Color Code: UNASSIGNED
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2021/A303
(8) Volcano Location: N 51 deg 47 min W 178 deg 47 min
(9) Area: Aleutians
(10) Summit Elevation: 5161 ft (1573 m)
(11) Volcanic Activity Summary: Data and communications from seismic stations at Gareloi were reestablished recently, allowing the Alaska Volcano Observatory to resume locating earthquakes and detecting unrest at this volcano. The aviation color code is now GREEN and the Volcano Alert Level is now designated as NORMAL.
(12) Volcanic cloud height: None
(13) Other volcanic cloud information: n/a
(14) Remarks:
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAF
dfee1@alaska.edu (907) 322-4085
(16) Next Notice:
2021-05-27 - Kilauea, Aviation Color Code: YELLOW (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20210527/0423Z)
(3) Volcano: Kilauea (VNUM #332010)
(4) Current Color Code: YELLOW
(5) Previous Color Code: ORANGE
(6) Source: Hawaiian Volcano Observatory
(7) Notice Number: 2021/H194
(8) Volcano Location: N 19 deg 25 min W 155 deg 17 min
(9) Area: Hawaii
(10) Summit Elevation: 4091 ft (1247 m)
(11) Volcanic Activity Summary: Kilauea Volcano is no longer erupting. Lava supply to the Halemaʻumaʻu lava lake has ceased and sulfur dioxide emissions have decreased to near pre-eruption background levels.

Accordingly, the USGS Hawaiian Volcano Observatory (HVO) is lowering the Volcano Alert Level for ground based hazards from WATCH to ADVISORY and the Aviation Color Code from ORANGE to YELLOW.

HVO continues to closely monitor Kīlauea Volcano for signs of renewed activity. Should volcanic activity change significantly a new Volcanic Activity Notice will be issued.

Hazards are still present on Kīlauea Volcano and are described below. Residents and visitors should stay informed and follow County of Hawai‘i and Hawaiʻi Volcanoes National Park guidelines.
(12) Volcanic cloud height: Minor fume emanating from previously active areas within Halemaʻumaʻu crater is producing a weak plume at the summit of Kīlauea. Visibility of the plume varies with humidity and temperature and may be stronger in the early morning.
(13) Other volcanic cloud information: None at this time.
(14) Remarks: Lava supply to the lava lake appears to have ceased between May 11th and 13th based upon elevation measurements of the lake surface that showed the surface was no longer rising. Dwindling lava supply over the previous month had caused the active lava lake to shrink to two small ponds by May 11th and was completely crusted over by May 20th. The last surface activity on the lake was observed on May 23nd. Changes in the lava lake have been accompanied by a drop in gas emissions to levels close to pre-eruption background level. Seismic tremor persistent during the eruption has weakened significantly but continues to indicate some shallow magmatic activity. Since May 11th, there has been weak inflation and an increase in shallow volcano tectonic earthquakes at the summit, suggesting magma entering the system is being stored at depth. These observations indicate that the eruption in Halema‘uma‘u at the summit of Kīlauea Volcano has paused. It is possible that the Halema‘uma‘u vent could resume eruption or that Kīlauea is entering a period of quiescence prior the next eruption.

HVO continues to closely monitor Kīlauea’s seismicity, deformation, and gas emissions, and maintains visual surveillance of the summit and the East Rift Zone for signs of renewed activity. There are currently no indications suggesting that a resumption of volcanic activity is imminent. Kīlauea remains an active volcano and future eruptions are possible at the summit or elsewhere on the volcano. Should volcanic activity change significantly a new Volcanic Activity Notice will be issued.

Continuing Hazards

Levels of volcanic gas (sulfur dioxide and carbon dioxide) can remain locally hazardous even though Kīlauea is no longer erupting. Sulfur dioxide (SO2) gas emissions have greatly decreased. However, local concentrations of sulfur dioxide (SO2) or hydrogen sulfide (H2S) may persist in downwind areas, and residents may from time to time notice odors of these gasses. Significant hazards also remain around Halemaʻumaʻu from crater wall instability, ground cracking, and rockfalls that can be enhanced by earthquakes within the area closed to the public.

More Information:
Kīlauea activity summary also available by phone: (808) 967-8862
Kīlauea webcam images: https://www.usgs.gov/volcanoes/kilauea/webcams
Kīlauea photos/video: https://www.usgs.gov/volcanoes/kilauea/photo-video-chronology
Kīlauea lava-flow maps: https://www.usgs.gov/volcanoes/kilauea/maps
Kīlauea FAQs: https://www.usgs.gov/volcanoes/kilauea/faqs
(15) Contacts: askHVO@usgs.gov
(16) Next Notice: The Hawaiian Volcano Observatory (HVO) continues to closely monitor Kīlauea's seismicity, deformation, and gas emissions for any sign of reactivation. HVO will continue to issue weekly Kīlauea updates on Tuesdays until further notice.

Subscribe to these messages:
https://volcanoes.usgs.gov/vns2/

Recent earthquakes in Hawaiʻi (map and list): https://www.usgs.gov/observatories/hawaiian-volcano-observatory/earthquakes

Explanation of Volcano Alert Levels and Aviation Color Codes: https://www.usgs.gov/natural-hazards/volcano-hazards/about-alert-levels
2021-05-26 - Great Sitkin, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20210526/1631Z)
(3) Volcano: Great Sitkin (VNUM #311120)
(4) Current Color Code: ORANGE
(5) Previous Color Code: RED
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2021/A299
(8) Volcano Location: N 52 deg 4 min W 176 deg 6 min
(9) Area: Aleutians
(10) Summit Elevation: 5709 ft (1740 m)
(11) Volcanic Activity Summary: A short-duration (1-2 minutes) explosive eruption occurred at 21:04 AKDT Tuesday May 25 (5:04 UTC 26 May) and resulted in an ash cloud up to 15,000 ft asl. Since that explosion, seismicity has decreased and satellite images show no further ash emissions. Thus, AVO is reducing the Aviation Color Code ORANGE and the Volcano Alert Level to WATCH. Additional explosive events are possible, but not certain.

The ash cloud from the initial explosive eruption is still visible in satellite images. See the NWS Alaska Aviation Weather Unit web page for current information. https://www.weather.gov/aawu/sigmets

Great Sitkin is monitored with a local real-time seismic network, which will typically allow AVO to detect changes in unrest that may lead to an explosive eruption. Rapid detection of an ash-producing eruption would be accomplished using a combination of seismic, infrasound, lightning, and satellite data.
(12) Volcanic cloud height: No current emissions
(13) Other volcanic cloud information: Drifting ash cloud still visible in satellite data
(14) Remarks: Great Sitkin Volcano is a basaltic andesite volcano that occupies most of the northern half of Great Sitkin Island, a member of the Andreanof Islands group in the central Aleutian Islands. It is located 43 km (26 miles) east of the community of Adak. The volcano is a composite structure consisting of an older dissected volcano and a younger parasitic cone with a 3-km-diameter summit crater. A steep-sided lava dome, emplaced during an eruption in 1974, occupies the center of the crater. Great Sitkin erupted at least three times in the 20th century, most recently in 1974. That eruption produced at least one ash cloud that likely exceeded an altitude of 25,000 ft above sea level. A poorly documented eruption occurred in 1945, also producing a lava dome that was partially destroyed in the 1974 eruption. Within the past 280 years a large explosive eruption produced pyroclastic flows that partially filled the Glacier Creek valley on the southwest flank.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAF
dfee1@alaska.edu (907) 322-4085
(16) Next Notice:
2021-05-26 - Great Sitkin, Aviation Color Code: RED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20210526/0603Z)
(3) Volcano: Great Sitkin (VNUM #311120)
(4) Current Color Code: RED
(5) Previous Color Code: RED
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2021/A298
(8) Volcano Location: N 52 deg 4 min W 176 deg 6 min
(9) Area: Aleutians
(10) Summit Elevation: 5709 ft (1740 m)
(11) Volcanic Activity Summary: A short-duration (1-2 minutes) explosive eruption began at 21:04 AKDT (5:04 UTC 26 May), resulting in an ash cloud up to 15,000 ft asl. Since that explosion, seismicity has decreased and satellite images show that the ash cloud has detached from the vent and is moving towards the east. Additional explosions are possible and the Aviation Color Code remains at RED and the Volcano Alert Level at WARNING.

Great Sitkin is monitored with a local real-time seismic network, which will typically allow AVO to detect changes in unrest that may lead to an explosive eruption. Rapid detection of an ash-producing eruption would be accomplished using a combination of seismic, infrasound, lightning, and satellite data.
(12) Volcanic cloud height: 15,000 ft asl
(13) Other volcanic cloud information: Detached from the vent and moving east
(14) Remarks: Great Sitkin Volcano is a basaltic andesite volcano that occupies most of the northern half of Great Sitkin Island, a member of the Andreanof Islands group in the central Aleutian Islands. It is located 43 km (26 miles) east of the community of Adak. The volcano is a composite structure consisting of an older dissected volcano and a younger parasitic cone with a 3-km-diameter summit crater. A steep-sided lava dome, emplaced during an eruption in 1974, occupies the center of the crater. Great Sitkin erupted at least three times in the 20th century, most recently in 1974. That eruption produced at least one ash cloud that likely exceeded an altitude of 25,000 ft above sea level. A poorly documented eruption occurred in 1945, also producing a lava dome that was partially destroyed in the 1974 eruption. Within the past 280 years a large explosive eruption produced pyroclastic flows that partially filled the Glacier Creek valley on the southwest flank.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAF
dfee1@alaska.edu (907) 322-4085
(16) Next Notice:
2021-05-26 - Great Sitkin, Aviation Color Code: RED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20210526/0530Z)
(3) Volcano: Great Sitkin (VNUM #311120)
(4) Current Color Code: RED
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2021/A297
(8) Volcano Location: N 52 deg 4 min W 176 deg 6 min
(9) Area: Aleutians
(10) Summit Elevation: 5709 ft (1740 m)
(11) Volcanic Activity Summary: Explosive eruption began at 21:04 AKDT (5:04 UTC 26 May) and is continuing, as confirmed by geophysical data and mariner observations. Initial mariner reports suggest the cloud is as high as 15,000 ft asl, but is still developing.

Great Sitkin is monitored with a local real-time seismic network, which will typically allow AVO to detect changes in unrest that may lead to an explosive eruption. Rapid detection of an ash-producing eruption would be accomplished using a combination of seismic, infrasound, lightning, and satellite data.
(12) Volcanic cloud height: 15,000 ft asl
(13) Other volcanic cloud information: still developing
(14) Remarks: Great Sitkin Volcano is a basaltic andesite volcano that occupies most of the northern half of Great Sitkin Island, a member of the Andreanof Islands group in the central Aleutian Islands. It is located 43 km (26 miles) east of the community of Adak. The volcano is a composite structure consisting of an older dissected volcano and a younger parasitic cone with a 3-km-diameter summit crater. A steep-sided lava dome, emplaced during an eruption in 1974, occupies the center of the crater. Great Sitkin erupted at least three times in the 20th century, most recently in 1974. That eruption produced at least one ash cloud that likely exceeded an altitude of 25,000 ft above sea level. A poorly documented eruption occurred in 1945, also producing a lava dome that was partially destroyed in the 1974 eruption. Within the past 280 years a large explosive eruption produced pyroclastic flows that partially filled the Glacier Creek valley on the southwest flank.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAF
dfee1@alaska.edu (907) 322-4085
(16) Next Notice:
2021-05-26 - Great Sitkin, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20210526/0343Z)
(3) Volcano: Great Sitkin (VNUM #311120)
(4) Current Color Code: ORANGE
(5) Previous Color Code: YELLOW
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2021/A296
(8) Volcano Location: N 52 deg 4 min W 176 deg 6 min
(9) Area: Aleutians
(10) Summit Elevation: 5709 ft (1740 m)
(11) Volcanic Activity Summary: Over the past day, there has been an increase in local earthquake activity. These data indicate an increased potential for eruptive activity at Great Sitkin. AVO is raising the Aviation Color Code to ORANGE and the Volcano Alert Level to WATCH.

Last week, elevated surface temperatures and sulfur dioxide emissions were observed in satellite data, and robust steaming was observed by AVO field crews on Adak Island.

Great Sitkin is monitored with a local real-time seismic network, which will typically allow AVO to detect changes in unrest that may lead to an explosive eruption. Rapid detection of an ash-producing eruption would be accomplished using a combination of seismic, infrasound, lightning, and satellite data.
(12) Volcanic cloud height: None
(13) Other volcanic cloud information: n/a
(14) Remarks: Great Sitkin Volcano is a basaltic andesite volcano that occupies most of the northern half of Great Sitkin Island, a member of the Andreanof Islands group in the central Aleutian Islands. It is located 43 km (26 miles) east of the community of Adak. The volcano is a composite structure consisting of an older dissected volcano and a younger parasitic cone with a 3-km-diameter summit crater. A steep-sided lava dome, emplaced during an eruption in 1974, occupies the center of the crater. Great Sitkin erupted at least three times in the 20th century, most recently in 1974. That eruption produced at least one ash cloud that likely exceeded an altitude of 25,000 ft above sea level. A poorly documented eruption occurred in 1945, also producing a lava dome that was partially destroyed in the 1974 eruption. Within the past 280 years a large explosive eruption produced pyroclastic flows that partially filled the Glacier Creek valley on the southwest flank.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAF
dfee1@alaska.edu (907) 322-4085
(16) Next Notice:
2021-05-19 - Semisopochnoi, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20210519/0518Z)
(3) Volcano: Semisopochnoi (VNUM #311060)
(4) Current Color Code: ORANGE
(5) Previous Color Code: YELLOW
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2021/A274
(8) Volcano Location: N 51 deg 55 min E 179 deg 35 min
(9) Area: Aleutians
(10) Summit Elevation: 2625 ft (800 m)
(11) Volcanic Activity Summary: Several small explosions were detected in regional infrasound data earlier today and a small ash cloud was observed in a satellite image from 15:21 (23:21 UTC) on May 17. As a result AVO is raising the Color Code to Orange and the Alert Level to Watch.

Small eruptions producing minor ash deposits within the vicinity of the active north crater of Mount Cerberus and ash clouds under 10,000 ft above sea level are typical of recent activity at Semisopochnoi. Weather clouds up to 15,000 ft above sea level currently obscure the volcano.
(12) Volcanic cloud height: unknown
(13) Other volcanic cloud information: Small ash clouds are likely being generated during explosions and are likely under 10,000 ft asl.
(14) Remarks: Semisopochnoi is monitored by satellite data, regional infrasound, and lightning detection instruments. An infrasound array on Adak Island may detect explosive emissions from Semisopochnoi with a slight delay (approximately 13 minutes) if atmospheric conditions permit.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAF
dfee1@alaska.edu (907) 322-4085
(16) Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at http://www.avo.alaska.edu
2021-05-13 - Ukinrek Maars, Aviation Color Code: GREEN (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20210513/0058Z)
(3) Volcano: Ukinrek Maars (VNUM #312131)
(4) Current Color Code: GREEN
(5) Previous Color Code: UNASSIGNED
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2021/A249
(8) Volcano Location: N 57 deg 50 min W 156 deg 30 min
(9) Area: Alaska Peninsula
(10) Summit Elevation: 299 ft (91 m)
(11) Volcanic Activity Summary: Communications with seismic stations in the Ukinrek Maars area have been reestablished allowing the Alaska Volcano Observatory to resume locating earthquakes and detecting unrest at these volcanoes. The aviation color code is now GREEN and the Volcano Alert Level is now designated as NORMAL.
(12) Volcanic cloud height: n/a
(13) Other volcanic cloud information: n/a
(14) Remarks:
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAF
dfee1@alaska.edu (907) 322-4085
(16) Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at
http://www.avo.alaska.edu
2021-05-13 - Ugashik-Peulik, Aviation Color Code: GREEN (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20210513/0058Z)
(3) Volcano: Ugashik-Peulik (VNUM #312130)
(4) Current Color Code: GREEN
(5) Previous Color Code: UNASSIGNED
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2021/A248
(8) Volcano Location: N 57 deg 45 min W 156 deg 22 min
(9) Area: Alaska Peninsula
(10) Summit Elevation: 4836 ft (1474 m)
(11) Volcanic Activity Summary: Communications with seismic stations in the Ugashik/Peulik area have been reestablished allowing the Alaska Volcano Observatory to resume locating earthquakes and detecting unrest at these volcanoes. The aviation color code is now GREEN and the Volcano Alert Level is now designated as NORMAL.

(12) Volcanic cloud height: n/a
(13) Other volcanic cloud information: n/a
(14) Remarks:
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAF
dfee1@alaska.edu (907) 322-4085
(16) Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at
http://www.avo.alaska.edu
2021-05-13 - Great Sitkin, Aviation Color Code: YELLOW (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20210513/0057Z)
(3) Volcano: Great Sitkin (VNUM #311120)
(4) Current Color Code: YELLOW
(5) Previous Color Code: GREEN
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2021/A250
(8) Volcano Location: N 52 deg 4 min W 176 deg 6 min
(9) Area: Aleutians
(10) Summit Elevation: 5709 ft (1740 m)
(11) Volcanic Activity Summary: Elevated surface temperatures have been observed in satellite images of Great Sitkin Volcano beginning in January and detections have increased over the past two months. Satellite detections of increased volcanic gas emissions have been observed beginning on May 10. In addition, there has been a slight increase in local seismicity over the past two days. These data indicate a potential for increased eruptive activity at Great Sitkin. As a result, AVO is raising the Aviation Color Code to YELLOW and the Volcano Alert Level to ADVISORY.

Great Sitkin is monitored with a local real-time seismic network, which will typically allow AVO to detect changes in unrest that may lead to an explosive eruption. Rapid detection of an ash-producing eruption would be accomplished using a combination of seismic, infrasound, lightning, and satellite data.
(12) Volcanic cloud height: n/a
(13) Other volcanic cloud information: n/a
(14) Remarks: Great Sitkin Volcano is a basaltic andesite volcano that occupies most of the northern half of Great Sitkin Island, a member of the Andreanof Islands group in the central Aleutian Islands. It is located 43 km (26 miles) east of the community of Adak. The volcano is a composite structure consisting of an older dissected volcano and a younger parasitic cone with a 3-km-diameter summit crater. A steep-sided lava dome, emplaced during an eruption in 1974, occupies the center of the crater. Great Sitkin erupted at least three times in the 20th century, most recently in 1974. That eruption produced at least one ash cloud that likely exceeded an altitude of 25,000 ft above sea level. A poorly documented eruption occurred in 1945, also producing a lava dome that was partially destroyed in the 1974 eruption. Within the past 280 years a large explosive eruption produced pyroclastic flows that partially filled the Glacier Creek valley on the southwest flank.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAF
dfee1@alaska.edu (907) 322-4085
(16) Next Notice:
2021-05-12 - Veniaminof, Aviation Color Code: UNASSIGNED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20210512/2113Z)
(3) Volcano: Veniaminof (VNUM #312070)
(4) Current Color Code: UNASSIGNED
(5) Previous Color Code: YELLOW
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2021/A247
(8) Volcano Location: N 56 deg 11 min W 159 deg 23 min
(9) Area: Alaska Peninsula
(10) Summit Elevation: 8225 ft (2507 m)
(11) Volcanic Activity Summary: No eruptive activity at Veniaminof has been observed in satellite or infrasound data since early April. The Alaska Volcano Observatory is downgrading the Aviation Color Code and Volcano Alert Level from YELLOW/ADVISORY to UNASSIGNED/UNASSIGNED. The UNASSIGNED status is a result of several seismic station outages impairing the ability of the AVO to assess seismic unrest at the volcano. These stations may come back online as snowpack decreases. Any eruptive activity or unrest may still be detected with the remaining seismic stations, in regional infrasound networks, through detection of lightning, and/or monitoring of satellite images.

Eruptive activity at Veniaminof usually consists of minor ash emissions, lava fountaining and lava flows from the small cone in the summit caldera. Ash emissions are typically confined to the summit crater, but larger events can result in ash fall in nearby communities and drifting airborne ash.
(12) Volcanic cloud height: n/a
(13) Other volcanic cloud information: n/a
(14) Remarks: Mount Veniaminof volcano is an andesitic stratovolcano with an ice-filled 10-km diameter summit caldera located on the Alaska Peninsula, 775 km (480 mi) southwest of Anchorage and 35 km (22 mi) north of Perryville. Veniaminof is one of the largest (~300 cubic km; 77 cubic mi) and most active volcanic centers in the Aleutian Arc and has erupted at least 14 times in the past 200 years. Recent eruptions in 1993-95, 2005, 2013, and 2018 all occurred at the intracaldera cone and lasted for several months. These eruptions produced lava spattering and fountaining, minor emissions of ash and gas, and small lava flows into intracaldera icefield. Minor ash-producing explosions occurred nearly annually between 2002 and 2010. Previous historical eruptions have produced ash plumes that reached 15,000 to 20,000 ft above sea level (1939, 1956, and 2018) and ash fallout that blanketed areas within about 40 km (25 mi) of the volcano (1939, 2018).
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAF
dfee1@alaska.edu (907) 322-4085
(16) Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at
http://www.avo.alaska.edu
2021-05-07 - Semisopochnoi, Aviation Color Code: YELLOW (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20210507/1916Z)
(3) Volcano: Semisopochnoi (VNUM #311060)
(4) Current Color Code: YELLOW
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2021/A231
(8) Volcano Location: N 51 deg 55 min E 179 deg 35 min
(9) Area: Aleutians
(10) Summit Elevation: 2625 ft (800 m)
(11) Volcanic Activity Summary: No ash emissions or explosions from Semisopochnoi have been detected in satellite or infrasound data since April 26. Partly cloudy satellite views this week have shown no recent ash deposits or elevated surface temperatures, and only steam was observed within the north crater of Mount Cerberus. Sulfur dioxide emissions were observed this week on May 1 and 5, signifying continued volcanic unrest. AVO is therefore lowering the Aviation Color Code and Volcano Alert Level to YELLOW/ADVISORY. AVO will continue to monitor activity at Semisopochnoi with satellite and regional infrasound data.

When occurring, small eruptions producing minor ash deposits within the vicinity of the active north crater of Mount Cerberus and ash clouds under 10,000 ft above sea level are typical of activity at Semisopochnoi.


(12) Volcanic cloud height: N/A
(13) Other volcanic cloud information: N/A
(14) Remarks: Semisopochnoi is monitored by satellite data, regional infrasound, and lightning detection instruments. An infrasound array on Adak Island may detect explosive emissions from Semisopochnoi with a slight delay (approximately 13 minutes) if atmospheric conditions permit.
(15) Contacts: Matt Haney, Acting Scientist-in-Charge, USGS
mhaney@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAF
dfee1@alaska.edu (907) 322-4085
(16) Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at http://www.avo.alaska.edu
2021-04-22 - Semisopochnoi, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20210422/2148Z)
(3) Volcano: Semisopochnoi (VNUM #311060)
(4) Current Color Code: ORANGE
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2021/A188
(8) Volcano Location: N 51 deg 55 min E 179 deg 35 min
(9) Area: Aleutians
(10) Summit Elevation: 2625 ft (800 m)
(11) Volcanic Activity Summary: Eruptive activity at Semisopochnoi has gradually increased over the last 24 hours. Satellite views of the volcano show a continuous plume extending 50 miles (80 km) to the south at approximately 8000 feet a.m.s.l. A regional infrasound array has detected this increase in activity. The aviation color code and alert level remain at ORANGE/WATCH; however, AVO will continue to monitor the activity with satellite and regional infrasound data.

Small eruptions producing minor ash deposits within the vicinity of the volcano and ash clouds under 10,000 ft above sea level are typical of activity at this volcano.


(12) Volcanic cloud height: 8000 ft a.m.s.l.
(13) Other volcanic cloud information: unknown
(14) Remarks: Semisopochnoi is monitored by satellite data, regional infrasound, and lightning detection instruments. An infrasound array on Adak Island may detect explosive emissions from Semisopochnoi with a slight delay (approximately 13 minutes) if atmospheric conditions permit.
(15) Contacts: Matt Haney, Acting Scientist-in-Charge, USGS
mhaney@usgs.gov (907) 786-7497

Jessica Larsen, Acting Coordinating Scientist, UAF
jflarsen@alaska.edu (907) 322-4085
(16) Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at http://www.avo.alaska.edu
2021-04-21 - Veniaminof, Aviation Color Code: YELLOW (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20210421/1854Z)
(3) Volcano: Veniaminof (VNUM #312070)
(4) Current Color Code: YELLOW
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2021/A181
(8) Volcano Location: N 56 deg 11 min W 159 deg 23 min
(9) Area: Alaska Peninsula
(10) Summit Elevation: 8225 ft (2507 m)
(11) Volcanic Activity Summary: Eruptive activity at Veniaminof has declined in the past weeks with no emissions observed since the low-level ash emissions on April 5. Seismicity has continued to decline, but remains above background levels. Because of the diminished activity, the Alaska Volcano Observatory is lowering the Aviation Color Code to YELLOW and the Volcano Alert Level to ADVISORY at Veniaminof volcano. AVO continues to monitor Veniaminof with a local seismic stations, remote infrasound and lightning networks, and satellite and webcam images.

Eruptive activity at Veniaminof usually consists of minor ash emissions, lava fountaining and lava flows from the small cone in the summit caldera. Ash emissions are typically confined to the summit crater, but larger events can result in ash fall in nearby communities and drifting airborne ash.
(12) Volcanic cloud height: Unknown
(13) Other volcanic cloud information: none
(14) Remarks: Mount Veniaminof volcano is an andesitic stratovolcano with an ice-filled 10-km diameter summit caldera located on the Alaska Peninsula, 775 km (480 mi) southwest of Anchorage and 35 km (22 mi) north of Perryville. Veniaminof is one of the largest (~300 cubic km; 77 cubic mi) and most active volcanic centers in the Aleutian Arc and has erupted at least 14 times in the past 200 years. Recent eruptions in 1993-95, 2005, 2013, and 2018 all occurred at the intracaldera cone and lasted for several months. These eruptions produced lava spattering and fountaining, minor emissions of ash and gas, and small lava flows into intracaldera icefield. Minor ash-producing explosions occurred nearly annually between 2002 and 2010. Previous historical eruptions have produced ash plumes that reached 15,000 to 20,000 ft above sea level (1939, 1956, and 2018) and ash fallout that blanketed areas within about 40 km (25 mi) of the volcano (1939, 2018).
(15) Contacts: Matt Haney, Acting Scientist-in-Charge, USGS
mhaney@usgs.gov (907) 786-7497

Jessica Larsen, Acting Coordinating Scientist, UAF
jflarsen@alaska.edu (907) 322-4085
(16) Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at
http://www.avo.alaska.edu
2021-04-20 - Ukinrek Maars, Aviation Color Code: UNASSIGNED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20210420/1935Z)
(3) Volcano: Ukinrek Maars (VNUM #312131)
(4) Current Color Code: UNASSIGNED
(5) Previous Color Code: GREEN
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2021/A177
(8) Volcano Location: N 57 deg 50 min W 156 deg 30 min
(9) Area: Alaska Peninsula
(10) Summit Elevation: 299 ft (91 m)
(11) Volcanic Activity Summary: The Alaska Volcano Observatory can no longer seismically monitor Ukinrek-Maars because of seismic station outages. As a result, AVO is unable to assess seismic unrest at this volcano. Because it is no longer seismically monitored, AVO will move from volcano alert level NORMAL and aviation color code GREEN to "UNASSIGNED." Additional seismic stations may come back online this spring as snowpack decreases. Any eruptive activity or unrest may still be detected with the remaining seismic stations, in regional infrasound networks, through detection of lightning, and/or monitoring of satellite images.
(12) Volcanic cloud height: Unknown
(13) Other volcanic cloud information: Unknown
(14) Remarks:
(15) Contacts: Matt Haney, Acting Scientist-in-Charge, USGS
mhaney@usgs.gov (907) 786-7497

Jessica Larsen, Acting Coordinating Scientist, UAF
jflarsen@alaska.edu (907) 322-4085
(16) Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at
http://www.avo.alaska.edu
2021-04-20 - Tanaga, Aviation Color Code: GREEN (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20210420/0022Z)
(3) Volcano: Tanaga (VNUM #311080)
(4) Current Color Code: GREEN
(5) Previous Color Code: UNASSIGNED
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2021/A175
(8) Volcano Location: N 51 deg 53 min W 178 deg 8 min
(9) Area: Aleutians
(10) Summit Elevation: 5925 ft (1806 m)
(11) Volcanic Activity Summary: Communication with two seismic stations has been reestablished. With four local seismic stations active, the Alaska Volcano Observatory can resume locating earthquakes and detect unrest at Tanaga. The Aviation Color Code is now GREEN and the Volcano Alert Level is now designated as NORMAL.

Any eruptive activity or unrest may also still be detected in regional infrasound networks, through detection of lightning, and/or monitoring of satellite images.
(12) Volcanic cloud height: Unknown
(13) Other volcanic cloud information: Unknown
(14) Remarks:
(15) Contacts: Aaron Wech, Acting Scientist-in-Charge, USGS
awech@usgs.gov (907) 786-7497

Jessica Larsen, Acting Coordinating Scientist, UAF
jflarsen@alaska.edu (907) 322-4085
(16) Next Notice:
2021-04-20 - Ugashik-Peulik, Aviation Color Code: UNASSIGNED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20210420/0019Z)
(3) Volcano: Ugashik-Peulik (VNUM #312130)
(4) Current Color Code: UNASSIGNED
(5) Previous Color Code: GREEN
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2021/A176
(8) Volcano Location: N 57 deg 45 min W 156 deg 22 min
(9) Area: Alaska Peninsula
(10) Summit Elevation: 4836 ft (1474 m)
(11) Volcanic Activity Summary: The Alaska Volcano Observatory can no longer seismically monitor Ugashik-Peulik because of seismic station outages. As a result, AVO is unable to assess seismic unrest at this volcano. Because it is no longer seismically monitored, AVO will move from volcano alert level NORMAL and aviation color code GREEN to "UNASSIGNED." Additional seismic stations may come back online this spring as snowpack decreases. Any eruptive activity or unrest may still be detected with the remaining seismic stations, in regional infrasound networks, through detection of lightning, and/or monitoring of satellite images.
(12) Volcanic cloud height: Unknown
(13) Other volcanic cloud information: Unknown
(14) Remarks:
(15) Contacts: Aaron Wech, Acting Scientist-in-Charge, USGS
awech@usgs.gov (907) 786-7497

Jessica Larsen, Acting Coordinating Scientist, UAF
jflarsen@alaska.edu (907) 322-4085
(16) Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at
http://www.avo.alaska.edu
2021-04-17 - Semisopochnoi, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20210417/2049Z)
(3) Volcano: Semisopochnoi (VNUM #311060)
(4) Current Color Code: ORANGE
(5) Previous Color Code: RED
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2021/A165
(8) Volcano Location: N 51 deg 55 min E 179 deg 35 min
(9) Area: Aleutians
(10) Summit Elevation: 2625 ft (800 m)
(11) Volcanic Activity Summary: Eruptive activity at Semisopochnoi has declined over the last 24 hours. Satellite views of the volcano have been mostly obscured, but a recent clearing suggests activity has declined and no significant ash plume was observed. As a result, AVO is lowering the Color Code to ORANGE and the Alert Level to WATCH. It is likely that low-level eruptive activity continues and may not be detected by regional infrasound sensors or above the low clouds in satellite data. AVO will continue to monitor the situation.

Small eruptions producing minor ash deposits within the vicinity of the volcano and ash clouds under 10,000 ft above sea level are typical of activity at this volcano.


(12) Volcanic cloud height: unknown
(13) Other volcanic cloud information: unknown
(14) Remarks: Semisopochnoi is monitored by satellite data, regional infrasound, and lightning detection instruments. An infrasound array on Adak Island may detect explosive emissions from Semisopochnoi with a slight delay (approximately 13 minutes) if atmospheric conditions permit.
(15) Contacts: Aaron Wech, Acting Scientist-in-Charge, USGS
awech@usgs.gov (907) 786-7497

Jessica Larsen, Acting Coordinating Scientist, UAF
jflarsen@alaska.edu (907) 322-4085
(16) Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at http://www.avo.alaska.edu
2021-04-16 - Semisopochnoi, Aviation Color Code: RED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20210416/0315Z)
(3) Volcano: Semisopochnoi (VNUM #311060)
(4) Current Color Code: RED
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2021/A161
(8) Volcano Location: N 51 deg 55 min E 179 deg 35 min
(9) Area: Aleutians
(10) Summit Elevation: 2625 ft (800 m)
(11) Volcanic Activity Summary: Satellite data suggests ash emissions from Semisopochnoi volcano have been ongoing since early this morning and are continuing with no decrease in intensity. The ash cloud extends more than 217 mi (350 km) southeast of the volcano with heights up to 20,000 feet (6 km) above sea level. Based on the length and height of the ash plume and sustained nature of ash emissions, AVO is raising the Color Code to RED and the Alert Level to WARNING. AVO will continue to monitor the situation.
(12) Volcanic cloud height: 20,000 feet above sea level or less.
(13) Other volcanic cloud information: Continuous ash cloud extends more than 350 km from volcano.
(14) Remarks: Semisopochnoi is monitored by satellite data, regional infrasound, and lightning detection instruments. An infrasound array on Adak Island may detect explosive emissions from Semisopochnoi with a slight delay (approximately 13 minutes) if atmospheric conditions permit.
(15) Contacts: Aaron Wech, Acting Scientist-in-Charge, USGS
awech@usgs.gov (907) 786-7497

Jessica Larsen, Acting Coordinating Scientist, UAF
jflarsen@alaska.edu (907) 322-4085
(16) Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at http://www.avo.alaska.edu
2021-04-16 - Semisopochnoi, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20210416/0024Z)
(3) Volcano: Semisopochnoi (VNUM #311060)
(4) Current Color Code: ORANGE
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2021/A160
(8) Volcano Location: N 51 deg 55 min E 179 deg 35 min
(9) Area: Aleutians
(10) Summit Elevation: 2625 ft (800 m)
(11) Volcanic Activity Summary: Satellite data suggests ash emissions from Semisopochnoi volcano have been ongoing since early this morning and are continuing. The ash cloud extends up to 217 mi (350 km) southeast of the volcano with heights up to 20,000 feet (6 km) above sea level. Based on the length and height of the ash plume and ongoing nature of ash emissions, AVO is issuing this update; the Color Code/Alert Level remains at ORANGE/WATCH. AVO will continue to monitor the situation.
(12) Volcanic cloud height: 20,000 feet above sea level. or less.
(13) Other volcanic cloud information: continuous ash cloud extends 350 km from volcano.
(14) Remarks: Semisopochnoi is monitored by satellite data, regional infrasound, and lightning detection instruments. An infrasound array on Adak Island may detect explosive emissions from Semisopochnoi with a slight delay (approximately 13 minutes) if atmospheric conditions permit.
(15) Contacts: Aaron Wech, Acting Scientist-in-Charge, USGS
awech@usgs.gov (907) 786-7497

Jessica Larsen, Acting Coordinating Scientist, UAF
jflarsen@alaska.edu (907) 322-4085
(16) Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at http://www.avo.alaska.edu
2021-04-05 - Veniaminof, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20210405/2023Z)
(3) Volcano: Veniaminof (VNUM #312070)
(4) Current Color Code: ORANGE
(5) Previous Color Code: YELLOW
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2021/A126
(8) Volcano Location: N 56 deg 11 min W 159 deg 23 min
(9) Area: Alaska Peninsula
(10) Summit Elevation: 8225 ft (2507 m)
(11) Volcanic Activity Summary: Likely low-level ash emissions were observed in web camera views of the summit. Seismic activity remains elevated. Because of the renewed activity, AVO is raising the Aviation Color Code to ORANGE and the Volcano Alert Level to WATCH at Veniaminof volcano. The Alaska Volcano Observatory continues to monitor Veniaminof with a local seismic network, remote infrasound and lightning networks, and satellite and webcam images.

Eruptive activity at Veniaminof usually consists of minor ash emissions, lava fountaining and lava flows from the small cone in the summit caldera. Ash emissions are typically confined to the summit crater, but larger events can result in ash fall in nearby communities and drifting airborne ash.
(12) Volcanic cloud height: 10000 feet A.M.S.L.
(13) Other volcanic cloud information: none
(14) Remarks: Mount Veniaminof volcano is an andesitic stratovolcano with an ice-filled 10-km diameter summit caldera located on the Alaska Peninsula, 775 km (480 mi) southwest of Anchorage and 35 km (22 mi) north of Perryville. Veniaminof is one of the largest (~300 cubic km; 77 cubic mi) and most active volcanic centers in the Aleutian Arc and has erupted at least 14 times in the past 200 years. Recent eruptions in 1993-95, 2005, 2013, and 2018 all occurred at the intracaldera cone and lasted for several months. These eruptions produced lava spattering and fountaining, minor emissions of ash and gas, and small lava flows into intracaldera icefield. Minor ash-producing explosions occurred nearly annually between 2002 and 2010. Previous historical eruptions have produced ash plumes that reached 15,000 to 20,000 ft above sea level (1939, 1956, and 2018) and ash fallout that blanketed areas within about 40 km (25 mi) of the volcano (1939, 2018).
(15) Contacts: Matt Haney, Acting Scientist-in-Charge, USGS
mhaney@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI
dfee1@alaska.edu (907) 322-4085
(16) Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at
http://www.avo.alaska.edu
2021-04-02 - Shishaldin, Aviation Color Code: GREEN (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20210402/1735Z)
(3) Volcano: Shishaldin (VNUM #311360)
(4) Current Color Code: GREEN
(5) Previous Color Code: UNASSIGNED
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2021/A109
(8) Volcano Location: N 54 deg 45 min W 163 deg 58 min
(9) Area: Aleutians
(10) Summit Elevation: 9373 ft (2857 m)
(11) Volcanic Activity Summary: Several seismic stations in the Shishaldin network are now operating after being offline for many months this winter. Data from these stations have improved the Alaska Volcano Observatory's monitoring capability, and allows for location of small local earthquakes, thus the Aviation Color Code is now GREEN and the Volcano Alert Level NORMAL.

The Alaska Volcano Observatory continues to monitor Shishaldin with the local seismic, GPS, and tilt stations, web camera imagery, remote infrasound and lightning networks, and satellite images.
(12) Volcanic cloud height: na
(13) Other volcanic cloud information: na
(14) Remarks: Shishaldin volcano, located near the center of Unimak Island in the eastern Aleutian Islands, is a spectacular symmetric cone with a base diameter of approximately 16 km (10 mi). A 200-m-wide (660 ft) funnel-shaped summit crater typically emits a steam plume and occasional small amounts of ash. Shishaldin is one of the most active volcanoes in the Aleutian volcanic arc, with at least 54 episodes of unrest including over 24 confirmed eruptions since 1775. Most eruptions are relatively small, although the April-May 1999 event generated an ash column that reached 45,000 ft above sea level.
(15) Contacts: Matthew Haney, Acting Scientist-in-Charge, USGS
mhaney@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI
dfee1@alaska.edu (907) 322-4085
(16) Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at http://www.avo.alaska.edu
2021-04-02 - Veniaminof, Aviation Color Code: YELLOW (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20210402/1733Z)
(3) Volcano: Veniaminof (VNUM #312070)
(4) Current Color Code: YELLOW
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2021/A116
(8) Volcano Location: N 56 deg 11 min W 159 deg 23 min
(9) Area: Alaska Peninsula
(10) Summit Elevation: 8225 ft (2507 m)
(11) Volcanic Activity Summary: The eruption of Veniaminof that started in late February 2021 appears to have paused. No ash emissions or steam plumes were visible during clear weather conditions on April 1. Elevated surface temperatures continue to be detected in satellite images, but are consistent with heat from recently erupted and now cooling lava flows. No significant seismicity or infrasound has been detected in the last 4 days. As a result, AVO is lowering the Aviation Color Code to YELLOW and the Volcano Alert Level to ADVISORY at Veniaminof volcano. Pauses in eruptions are common, and lava flows and eruption of minor ash plumes could resume suddenly with little or no warning. The Alaska Volcano Observatory continues to monitor Veniaminof with a local seismic network, remote infrasound and lightning networks, and satellite and webcam images.

Eruptive activity at Veniaminof usually consists of minor ash emissions, lava fountaining and lava flows from the small cone in the summit caldera. Ash emissions are typically confined to the summit crater, but larger events can result in ash fall in nearby communities and drifting airborne ash.
(12) Volcanic cloud height: none
(13) Other volcanic cloud information: none
(14) Remarks: Mount Veniaminof volcano is an andesitic stratovolcano with an ice-filled 10-km diameter summit caldera located on the Alaska Peninsula, 775 km (480 mi) southwest of Anchorage and 35 km (22 mi) north of Perryville. Veniaminof is one of the largest (~300 cubic km; 77 cubic mi) and most active volcanic centers in the Aleutian Arc and has erupted at least 14 times in the past 200 years. Recent eruptions in 1993-95, 2005, 2013, and 2018 all occurred at the intracaldera cone and lasted for several months. These eruptions produced lava spattering and fountaining, minor emissions of ash and gas, and small lava flows into intracaldera icefield. Minor ash-producing explosions occurred nearly annually between 2002 and 2010. Previous historical eruptions have produced ash plumes that reached 15,000 to 20,000 ft above sea level (1939, 1956, and 2018) and ash fallout that blanketed areas within about 40 km (25 mi) of the volcano (1939, 2018).
(15) Contacts: Matthew Haney, Acting Scientist-in-Charge, USGS
mhaney@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI
dfee1@alaska.edu (907) 322-4085
(16) Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at
http://www.avo.alaska.edu
2021-03-31 - Tanaga, Aviation Color Code: UNASSIGNED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20210331/1822Z)
(3) Volcano: Tanaga (VNUM #311080)
(4) Current Color Code: UNASSIGNED
(5) Previous Color Code: GREEN
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2021/A108
(8) Volcano Location: N 51 deg 53 min W 178 deg 8 min
(9) Area: Aleutians
(10) Summit Elevation: 5925 ft (1806 m)
(11) Volcanic Activity Summary: Low power likely due to snow cover has resulted in loss of operation and communication with all but two seismic stations on Tanaga. As a result, the Alaska Volcano Observatory can no longer locate earthquakes that could indicate unrest at Tanaga, and the Aviation Color Code and the Volcano Alert Level are now designated as UNASSIGNED. Additional seismic stations may come back online this spring as snowpack decreases.

Any eruptive activity or unrest may still be detected with the remaining seismic stations, in regional infrasound networks, through detection of lightning, and/or monitoring of satellite images.
(12) Volcanic cloud height: Unknown
(13) Other volcanic cloud information: Unknown
(14) Remarks:
(15) Contacts: Matthew Haney, Acting Scientist-in-Charge, USGS
mhaney@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI
dfee1@alaska.edu (907) 322-4085
(16) Next Notice:
2021-03-31 - Gareloi, Aviation Color Code: UNASSIGNED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20210331/1821Z)
(3) Volcano: Gareloi (VNUM #311070)
(4) Current Color Code: UNASSIGNED
(5) Previous Color Code: GREEN
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2021/A107
(8) Volcano Location: N 51 deg 47 min W 178 deg 47 min
(9) Area: Aleutians
(10) Summit Elevation: 5161 ft (1573 m)
(11) Volcanic Activity Summary: Low power likely due to snow cover has resulted in loss of operation and communication with all seismic stations on Gareloi. As a result, the Alaska Volcano Observatory can no longer locate earthquakes or detect seismic signals that could indicate unrest at Gareloi volcano, and the Aviation Color Code and the Volcano Alert Level are now designated as UNASSIGNED. Seismic stations may come back online this spring as snowpack decreases.

Any eruptive activity may still be detected, although with some delay, with regional infrasound networks, detection of lightning, and monitoring of satellite images.
(12) Volcanic cloud height: Unknown
(13) Other volcanic cloud information: Unknown
(14) Remarks:
(15) Contacts: Matthew Haney, Acting Scientist-in-Charge, USGS
mhaney@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI
dfee1@alaska.edu (907) 322-4085
(16) Next Notice:
2021-03-20 - Cleveland, Aviation Color Code: YELLOW (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20210320/2144Z)
(3) Volcano: Cleveland (VNUM #311240)
(4) Current Color Code: YELLOW
(5) Previous Color Code: UNASSIGNED
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2021/A75
(8) Volcano Location: N 52 deg 49 min W 169 deg 56 min
(9) Area: Aleutians
(10) Summit Elevation: 5676 ft (1730 m)
(11) Volcanic Activity Summary: Satellite detections of increased volcanic gas emissions and elevated surface temperatures have been observed at Cleveland Volcano beginning on March 17, 2020. In addition, a local earthquake occurred on March 10 and it was large enough to be measured on seismometers 100 km away on Umnak Island. These data indicate a potential for increased eruptive activity at Cleveland. As a result, AVO is raising the Aviation Color Code to YELLOW and the Volcano Alert Level to ADVISORY.

Cleveland last erupted on June 2, 2020 AKDT (June 1, 2020 UTC) producing a small ash cloud to 22,000 ft. Explosions from Cleveland typically produce relatively small volcanic ash clouds that dissipate within hours; however, more significant ash emissions are possible.
(12) Volcanic cloud height: none
(13) Other volcanic cloud information: n/a
(14) Remarks: Cleveland Volcano is monitored with a limited real-time seismic network. This smaller network inhibits AVO's ability to detect precursory unrest that may lead to an explosive eruption. Rapid detection of an ash-producing eruption may be possible using a combination of seismic, infrasound, lightning, and satellite data.
(15) Contacts: Matthew Haney, Acting Scientist-in-Charge, USGS
mhaney@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI
dfee1@alaska.edu (907) 322-4085
(16) Next Notice:
2021-03-19 - Semisopochnoi, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20210319/1346Z)
(3) Volcano: Semisopochnoi (VNUM #311060)
(4) Current Color Code: ORANGE
(5) Previous Color Code: YELLOW
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2021/A70
(8) Volcano Location: N 51 deg 55 min E 179 deg 35 min
(9) Area: Aleutians
(10) Summit Elevation: 2625 ft (800 m)
(11) Volcanic Activity Summary: Regional infrasound sensors detected a small explosion from Semisopochnoi volcano this morning at 11:50 UTC (03:50 AKDT), indicating an increase in eruptive activity. As a result, AVO is raising the Aviation Color Code to ORANGE and the Volcano Alert Level to WATCH. Cloudy weather conditions are obscuring satellite views of the volcano. It is unknown if the explosion produced a low-level ash cloud or local ash deposit.

Small eruptions producing minor ash deposits within the vicinity of the volcano are typical of activity during unrest at Semisopochnoi since September 2018. Local seismic stations have been offline since November 11, 2020. New explosions could occur at anytime with no warning.
(12) Volcanic cloud height: n/a
(13) Other volcanic cloud information: n/a
(14) Remarks: Semisopochnoi is monitored remotely by satellite and lightning sensors. An infrasound array on Adak Island could detect explosive emissions from Semisopochnoi with a 13 minute delay if atmospheric conditions permit.
(15) Contacts: Matthew Haney, Acting Scientist-in-Charge, USGS
mhaney@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI
dfee1@alaska.edu (907) 322-4085
(16) Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at http://www.avo.alaska.edu
2021-03-04 - Veniaminof, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20210304/1804Z)
(3) Volcano: Veniaminof (VNUM #312070)
(4) Current Color Code: ORANGE
(5) Previous Color Code: UNASSIGNED
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2021/A39
(8) Volcano Location: N 56 deg 11 min W 159 deg 23 min
(9) Area: Alaska Peninsula
(10) Summit Elevation: 8225 ft (2507 m)
(11) Volcanic Activity Summary: Regional infrasound sensors detected a small explosion from Veniaminof volcano this morning at 14:13 UTC (05:13 local time). Satellite and webcam views indicate low-elevation (< 10,000 ft asl) ash emissions heading in the SSE direction, and minor ash deposits are visible at the volcano. As a result, AVO is raising the Aviation Color Code to ORANGE and the Volcano Alert Level to WATCH at Veniaminof volcano. The local seismic data remains offline due to an outage of a satellite link at Port Heiden. However, the Alaska Volcano Observatory continues to monitor Veniaminof with satellite and webcam data and remote infrasound, seismic and lightning networks.

Eruptive activity usually consists of minor ash emissions, lava fountaining and lava flows from the small cone in the summit caldera. Ash emissions are typically confined to the summit crater, but larger events can result in ash fall in nearby communities and drifting airborne ash.
(12) Volcanic cloud height: 10000 feet asl
(13) Other volcanic cloud information: SSE direction
(14) Remarks: Mount Veniaminof volcano is an andesitic stratovolcano with an ice-filled 10-km diameter summit caldera located on the Alaska Peninsula, 775 km (480 mi) southwest of Anchorage and 35 km (22 mi) north of Perryville. Veniaminof is one of the largest (~300 cubic km; 77 cubic mi) and most active volcanic centers in the Aleutian Arc and has erupted at least 14 times in the past 200 years. Recent eruptions in 1993-95, 2005, 2013, and 2018 all occurred at the intracaldera cone and lasted for several months. These eruptions produced lava spattering and fountaining, minor emissions of ash and gas, and small lava flows into intracaldera icefield. Minor ash-producing explosions occurred nearly annually between 2002 and 2010. Previous historical eruptions have produced ash plumes that reached 15,000 to 20,000 ft above sea level (1939, 1956, and 2018) and ash fallout that blanketed areas within about 40 km (25 mi) of the volcano (1939, 2018).
(15) Contacts: Dave Schneider, Acting Scientist-in-Charge, USGS
djschneider@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI
dfee1@alaska.edu (907) 322-4085
(16) Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at
http://www.avo.alaska.edu
2021-02-19 - Semisopochnoi, Aviation Color Code: YELLOW (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20210219/1828Z)
(3) Volcano: Semisopochnoi (VNUM #311060)
(4) Current Color Code: YELLOW
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2021/A24
(8) Volcano Location: N 51 deg 55 min E 179 deg 35 min
(9) Area: Aleutians
(10) Summit Elevation: 2625 ft (800 m)
(11) Volcanic Activity Summary: No significant volcanic activity has been detected at Semisopochnoi in satellite or regional infrasound data since February 6 and 7 when several small ash deposits were observed in satellite imagery. As a result, the Alaska Volcano Observatory is decreasing the Aviation Color Code to YELLOW and the Volcano Alert Level to ADVISORY.

Small eruptions producing minor ash deposits within the vicinity of the volcano are typical of activity during unrest at Semisopochnoi since September 2018. Local seismic stations have been offline since November 11, 2020. New explosions could occur at anytime with no warning.
(12) Volcanic cloud height: n/a
(13) Other volcanic cloud information: n/a
(14) Remarks: Semisopochnoi is monitored remotely by satellite and lightning sensors. An infrasound array on Adak Island could detect explosive emissions from Semisopochnoi with a 13 minute delay if atmospheric conditions permit.
(15) Contacts: Matt Haney, Acting Scientist-in-Charge, USGS
mhaney@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI
dfee1@alaska.edu (907) 322-4085
(16) Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at http://www.avo.alaska.edu
2021-02-08 - Semisopochnoi, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20210208/2311Z)
(3) Volcano: Semisopochnoi (VNUM #311060)
(4) Current Color Code: ORANGE
(5) Previous Color Code: YELLOW
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2021/A13
(8) Volcano Location: N 51 deg 55 min E 179 deg 35 min
(9) Area: Aleutians
(10) Summit Elevation: 2625 ft (800 m)
(11) Volcanic Activity Summary: High-resolution satellite imagery on February 7 shows a second small ash deposit extending at least 3 km to the northeast from North Cerberus Crater on Semisopochnoi Island, similar to the first observed on February 6. Clouds obscured views into the crater and the southern side of the volcano. Any ash clouds associated with these deposits have not been observed and are likely low-level (<10,000 ft) and short-duration. Because of evidence for continued low-level ash emissions, the Alaska Volcano Observatory is increasing the Aviation Color Code to ORANGE and the Volcano Alert Level to WATCH.

Small eruptions producing minor ash deposits within the vicinity of the volcano are typical of activity during unrest at Semisopochnoi since September 2018. Local seismic stations have been offline since November 11, 2020. New explosions could occur at anytime with no warning.
(12) Volcanic cloud height: n/a
(13) Other volcanic cloud information: n/a
(14) Remarks: Semisopochnoi is monitored remotely by satellite and lightning sensors. An infrasound array on Adak Island could detect explosive emissions from Semisopochnoi with a 13 minute delay if atmospheric conditions permit.
(15) Contacts: Matt Haney, Acting Scientist-in-Charge, USGS
mhaney@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI
dfee1@alaska.edu (907) 322-4085
(16) Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at http://www.avo.alaska.edu
2021-02-07 - Semisopochnoi, Aviation Color Code: YELLOW (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20210207/0451Z)
(3) Volcano: Semisopochnoi (VNUM #311060)
(4) Current Color Code: YELLOW
(5) Previous Color Code: UNASSIGNED
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2021/A11
(8) Volcano Location: N 51 deg 55 min E 179 deg 35 min
(9) Area: Aleutians
(10) Summit Elevation: 2625 ft (800 m)
(11) Volcanic Activity Summary: High-resolution satellite images on February 6 showed a small ash deposit extending less than 3 km to the north from North Cerebus Crater on Semisopochnoi Island. Steam emissions obscured views into the crater. There is no evidence for continuing activity, but observation of a new deposit suggests renewed unrest, and the Alaska Volcano Observatory is increasing the Aviation Color Code to YELLOW and the Volcano Alert Level to ADVISORY.

Small eruptions producing minor ash deposits within the vicinity of the volcano are typical of activity during unrest at Semisopochnoi since September 2018, with the last detected activity in June 2020. Local seismic stations have been offline since November 11, 2020. New explosions could occur at anytime with no warning.
(12) Volcanic cloud height: n/a
(13) Other volcanic cloud information: n/a
(14) Remarks: Semisopochnoi is monitored remotely by satellite and lightning sensors. An infrasound array on Adak Island could detect explosive emissions from Semisopochnoi with a 13 minute delay if atmospheric conditions permit.
(15) Contacts: Matt Haney, Acting Scientist-in-Charge, USGS
mhaney@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI
dfee1@alaska.edu (907) 322-4085
(16) Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at http://www.avo.alaska.edu
2021-01-15 - Shishaldin, Aviation Color Code: UNASSIGNED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20210115/2134Z)
(3) Volcano: Shishaldin (VNUM #311360)
(4) Current Color Code: UNASSIGNED
(5) Previous Color Code: GREEN
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2021/A4
(8) Volcano Location: N 54 deg 45 min W 163 deg 58 min
(9) Area: Aleutians
(10) Summit Elevation: 9373 ft (2857 m)
(11) Volcanic Activity Summary: The Shishaldin network has several outages affecting GPS, seismic, and infrasound stations. Due to the impaired local monitoring stations, the Alaska Volcano Observatory is changing the Aviation Color Code and the Volcano Alert Level UNASSIGNED/UNASSIGNED.

This most recent eruptive cycle at Shishaldin began in July 2019 with pauses in activity in late September/early October 2019 and February 2020. The most recent activity in mid-March was confined to the summit crater except for minor ash deposits near the summit. Only minor rockfalls within the summit crater, not associated with eruptive activity, have been detected since early April. Pauses in eruptions are common at Shishaldin, and therefore eruptive activity could resume with little warning. The Alaska Volcano Observatory will continue to monitor the volcano closely.

The Alaska Volcano Observatory continues to monitor Shishaldin with the local web camera imagery, satellite data and remote infrasound, seismic and lightning networks.
(12) Volcanic cloud height: na
(13) Other volcanic cloud information: na
(14) Remarks: Shishaldin volcano, located near the center of Unimak Island in the eastern Aleutian Islands, is a spectacular symmetric cone with a base diameter of approximately 16 km (10 mi). A 200-m-wide (660 ft) funnel-shaped summit crater typically emits a steam plume and occasional small amounts of ash. Shishaldin is one of the most active volcanoes in the Aleutian volcanic arc, with at least 54 episodes of unrest including over 24 confirmed eruptions since 1775. Most eruptions are relatively small, although the April-May 1999 event generated an ash column that reached 45,000 ft above sea level.
(15) Contacts: Matt Haney, Acting Scientist-in-Charge, USGS
mhaney@usgs.gov (907) 786-7497

Taryn Lopez, Acting Coordinating Scientist, UAF
tmlopez@alaska.edu (907) 322-4085
(16) Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at http://www.avo.alaska.edu
2021-01-15 - Veniaminof, Aviation Color Code: UNASSIGNED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20210115/2133Z)
(3) Volcano: Veniaminof (VNUM #312070)
(4) Current Color Code: UNASSIGNED
(5) Previous Color Code: GREEN
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2021/A3
(8) Volcano Location: N 56 deg 11 min W 159 deg 23 min
(9) Area: Alaska Peninsula
(10) Summit Elevation: 8225 ft (2507 m)
(11) Volcanic Activity Summary: Data from the Veniaminof seismic network have not been received since December 8, 2020 due in part to an outage of a satellite link to Port Heiden. Repair efforts are underway, however, due to the absence of local seismic monitoring, the Alaska Volcano Observatory is changing the Aviation Color Code and the Volcano Alert Level UNASSIGNED/UNASSIGNED.

The Alaska Volcano Observatory continues to monitor Veniaminof with satellite data and remote infrasound, seismic and lightning networks.
(12) Volcanic cloud height: None
(13) Other volcanic cloud information: n/a
(14) Remarks: Mount Veniaminof volcano is an andesitic stratovolcano with an ice-filled 10-km diameter summit caldera located on the Alaska Peninsula, 775 km (480 mi) southwest of Anchorage and 35 km (22 mi) north of Perryville. Veniaminof is one of the largest (~300 cubic km; 77 cubic mi) and most active volcanic centers in the Aleutian Arc and has erupted at least 14 times in the past 200 years. Recent eruptions in 1993-95, 2005, 2013, and 2018 all occurred at the intracaldera cone and lasted for several months. These eruptions produced lava spattering and fountaining, minor emissions of ash and gas, and small lava flows into intracaldera icefield. Minor ash-producing explosions occurred nearly annually between 2002 and 2010. Previous historical eruptions have produced ash plumes that reached 15,000 to 20,000 ft above sea level (1939, 1956, and 2018) and ash fallout that blanketed areas within about 40 km (25 mi) of the volcano (1939, 2018).
(15) Contacts: Matt Haney, Acting Scientist-in-Charge, USGS
mhaney@usgs.gov (907) 786-7497

Taryn Lopez, Acting Coordinating Scientist, UAF
tmlopez@alaska.edu (907) 322-4085
(16) Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at
http://www.avo.alaska.edu
2020-12-21 - Kilauea, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20201221/2014Z)
(3) Volcano: Kilauea (VNUM #332010)
(4) Current Color Code: ORANGE
(5) Previous Color Code: RED
(6) Source: Hawaiian Volcano Observatory
(7) Notice Number: 2020/H121
(8) Volcano Location: N 19 deg 25 min W 155 deg 17 min
(9) Area: Hawaii
(10) Summit Elevation: 4091 ft (1247 m)
(11) Volcanic Activity Summary: Kīlauea Volcano is erupting. At 9:30 p.m. HST on December 20, the USGS Hawaiian Volcano Observatory (HVO) detected glow within Halemaʻumaʻu crater at the summit of Kīlauea Volcano, indicating that an eruption had commenced within Kīlauea’s summit caldera. Due to the presence of the water lake at the summit of Kīlauea and the potential for steam-driven explosions and related hazards, HVO elevated Kīlauea’s volcano alert level to WARNING and its aviation color code to RED on December 20 as the progression of events was uncertain.

The water lake at the summit of Kīlauea has boiled away and an effusive eruption has commenced, with three vents in the wall of Halemaʻumaʻu crater generating lava flows that are contributing to a growing lava lake at the base of Halemaʻumaʻu crater. The eruption is currently confined to Halemaʻumaʻu crater.

HVO has decreased Kīlauea’s volcano alert level to WATCH and its aviation color code to ORANGE, reflecting the less-hazardous nature of the ongoing eruption.

Alert levels and aviation color codes are explained here: https://www.usgs.gov/natural-hazards/volcano-hazards/about-alert-levels

HVO continues to monitor the volcano closely and will report any significant changes.

Stay informed about Kīlauea by following volcano updates and tracking current monitoring data on the HVO web page (https://www.usgs.gov/volcanoes/kilauea/volcano-updates) or by signing up to receive updates by email at this site: https://volcanoes.usgs.gov/vns2/.

HVO is in constant communication with Hawai‘i Volcanoes National Park as this situation evolves. The eruption is currently taking place entirely within the park.

HVO is in constant communication with the County of Hawai‘i Civil Defense Agency.

Recent Observations:

An earthquake swarm beneath Kīlauea summit began around 8:30 p.m. HST on the evening of December 20, accompanied by ground deformation detected by tiltmeters. A bright glow and vigorous steam plume, generated by the boiling water lake in Halemaʻumaʻu, was subsequently observed on HVO webcams beginning approximately 9:30 p.m. HST. HVO scientists responded immediately and visually confirmed from the field that lava was visible within Halemaʻumaʻu. The steam plume dissipated shortly thereafter. Activity over the past ten hours has been characterized by three fissure vents on the north and northwest walls of Halemaʻumaʻu crater. Fountaining lava at these vents is estimated to be up to 25 m (82 ft) high; the vents are feeding lava flows into the base of Halemaʻumaʻu crater, which is being filled with a growing lava lake.

The lava lake has been rising approximately several meters (yards) an hour since the eruption began. The current lava lake exhibits a circulating perimeter, but stagnant center.

The event has been accompanied by only moderate amounts of deformation, indicating deflation of a magma reservoir under Halema’uma’u. Rates of tilting have decreased slightly since the beginning of the eruption.

Increased rates of seismicity in the summit region continue. Some of these earthquakes may be felt. A magnitude-4.4 earthquake located beneath Kīlauea Volcano's south flank occurred on Sunday, December 20, at 10:36 p.m. HST.

Visitors to the Hawai'i Volcanoes National Park should note that under southerly (non-trade) wind conditions, rockfalls and explosions can result in a dusting of powdery to gritty ash composed of volcanic glass and rock fragments. These ashfalls represent a minor hazard, but visitors should be aware that dustings of ash at areas around the Kīlauea summit are possible.

For more information on gas hazards at the summit of Kīlauea, please see: https://pubs.er.usgs.gov/publication/fs20173017

For more information about volcanic ash hazards and precautions at Kīlauea, please see: http://hvo.wr.usgs.gov/hazards/FAQ_SO2-Vog-Ash/main.html

For discussion of Kīlauea hazards, please see:

https://www.usgs.gov/observatories/hawaiian-volcano-observatory/hazards
(12) Volcanic cloud height: unknown
(13) Other volcanic cloud information: unknown
(14) Remarks: Hazard Analysis:

Background


Kīlauea Volcano had maintained a low level of non-eruptive unrest since the end of the 2018 lower East Rift Zone eruption and summit collapse, which deepened Halemaʻumaʻu crater by over 500 meters (1640 feet). Following the 2018 eruption, ground deformation rates indicated steady inflation of Kīlauea’s summit and at the end of 2018, the HVO monitoring network detected Deflation-Inflation events (DI-events) indicative that the shallow Halemaʻumaʻu magma reservoir, located approximately 1.6 km (1 mile) under Kīlauea caldera, still contained significant amounts of magma.

In late July 2019, ponded water appeared at the base of the deepest collapsed area of Kīlauea’s summit, within the Halemaʻumaʻu crater. The body of water grew into a lake as the water sought equilibrium with the surrounding groundwater.

Beginning in September 2020, increased rates of uplift were observed by Global Positioning System (GPS) stations in Kīlauea’s upper East Rift Zone and over the past month were observed in Kīlauea’s summit region.

In late November 2020, increased earthquake rates began when seismic stations recorded an average of at least 480 shallow, small-magnitude earthquakes (97% of which were less than or equal to magnitude-2) per week occurring at depths of less than 4 km (2.5 miles) beneath Kīlauea's summit and upper East Rift Zone. This compares to a rate of fewer than 180 per week following the end of Kīlauea’s 2018 eruption and through early November 2020.

On December 2, 2020, GPS stations and tiltmeters recorded a ground deformation event at Kīlauea’s summit indicative of a small dike intrusion of magma under the southern part of Kīlauea caldera.

On December 17, 2020, seismometers detected a notable increase in occurrence and duration of long-period seismic signals beneath Kīlauea’s summit, which are attributed to magmatic activity. Whereas this type of seismicity was observed on average once every few weeks following the 2018 eruption, rates have increased to over a dozen in the past several days.

Other monitoring data streams including volcanic gas and webcam imagery were stable until this eruption commenced.

Prognosis:

It is unclear how long the current eruption will continue. Kīlauea summit eruptions over the past 200 years have lasted from less than a day to more than a decade. HVO continues to monitor the ongoing eruption and all aspects of the volcano closely; HVO will report any significant changes.

Stay informed about Kīlauea by following volcano updates and tracking current monitoring data on the HVO web page (https://www.usgs.gov/volcanoes/kilauea/volcano-updates) or by signing up to receive updates by email at this site: https://volcanoes.usgs.gov/vns2/.

HVO is in constant communication with National Park Service and County of Hawai‘i County Civil Defense and other agencies responsible for public safety.

HVO is in constant communication with the County of Hawai‘i Civil Defense Agency. If anything develops that may affect your safety, you will be informed. Please sign up for Civil Defense notifications by visiting the County of Hawai‘i Civil Defense Agency webpage at http://www.hawaiicounty.gov/civil-defense/.

Contacts: askHVO@usgs.gov

Next Notice: Kīlauea updates will be issued daily. Should volcanic activity change significantly a new VAN will be issued. Regularly scheduled updates are posted at https://www.usgs.gov/hvo

The Hawaiian Volcano Observatory is one of five volcano observatories within the U.S. Geological Survey and is responsible for monitoring volcanoes and earthquakes in Hawaiʻi.

Hazard Analysis:

[General hazards]

High levels of volcanic gas, rockfalls, explosions, and volcanic glass particles are the primary hazards of concern regarding this new activity at Kīlauea’s summit.

Large amounts of volcanic gas—primarily water vapor (H2O), carbon dioxide (CO2), and sulfur dioxide (SO2)—are continuously released during eruptions of Kīlauea Volcano. As SO2 is released from the summit during this new eruption, it will react in the atmosphere with oxygen, sunlight, moisture, and other gases and particles, and within hours to days, convert to fine particles. The particles scatter sunlight and cause the visible haze that has been observed downwind of Kīlauea, known as vog (volcanic smog), during previous summit eruptions. Vog creates the potential for airborne health hazards to residents and visitors, damages agricultural crops and other plants, and affects livestock operations.

Rockfalls and minor explosions, such as the ones that occurred during the 2008–2018 lava lake eruption at Kīlauea summit, may occur suddenly and without warning. This underscores the extremely hazardous nature of Kīlauea caldera rim surrounding Halemaʻumaʻu crater, an area that has been closed to the public since late 2007.

Pele's hair and other lightweight volcanic glass fragments from the lava fountains within Halemaʻumaʻu will fall downwind of the fissure vents and lava lake, dusting the ground within a few hundred meters (yards) of the vent. High winds may waft lighter particles to greater distances. Residents are urged to minimize exposure to these volcanic particles, which can cause skin and eye irritation similar to volcanic ash.
(15) Contacts: askHVO@usgs.gov
(16) Next Notice: The Hawaiian Volcano Observatory (HVO) continues to closely monitor Kīlauea's seismicity, deformation, and gas emissions for any sign of reactivation. HVO will continue to issue weekly Kīlauea updates on Tuesdays until further notice.
2020-12-21 - Kilauea, Aviation Color Code: RED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20201221/0841Z)
(3) Volcano: Kilauea (VNUM #332010)
(4) Current Color Code: RED
(5) Previous Color Code: GREEN
(6) Source: Hawaiian Volcano Observatory
(7) Notice Number: 2020/H120
(8) Volcano Location: N 19 deg 25 min W 155 deg 17 min
(9) Area: Hawaii
(10) Summit Elevation: 4091 ft (1247 m)
(11) Volcanic Activity Summary: Shortly after approximately 9:30 p.m. HST, the USGS Hawaiian Volcano Observatory (HVO) detected glow within Halemaʻumaʻu crater at the summit of Kīlauea Volcano. An eruption has commenced within Kīlauea’s summit caldera. The situation is rapidly evolving and HVO will issue another statement when more information is available.

Accordingly, HVO has elevated Kīlauea’s volcano alert level to WARNING and its aviation color code to RED.

Alert levels and aviation color codes are explained here: https://www.usgs.gov/natural-hazards/volcano-hazards/about-alert-levels

HVO continues to monitor the volcano closely and will report any significant changes.

Stay informed about Kīlauea by following volcano updates and tracking current monitoring data on the HVO web page (https://www.usgs.gov/volcanoes/kilauea/volcano-updates) or by signing up to receive updates by email at this site: https://volcanoes.usgs.gov/vns2/.

HVO is in communication with Hawai‘i Volcanoes National Park as this situation, which is taking place within the park, evolves.

HVO is in contact with the County of Hawai‘i Civil Defense Agency.

Recent Observations:

For the past several weeks, the USGS Hawaiian Volcano Observatory (HVO) has recorded ground deformation and earthquake rates at Kīlauea Volcano’s summit and upper East Rift Zone that have exceeded background levels observed since the conclusion of the 2018 lower East Rift Zone eruption and summit collapse.

Beginning in September 2020, increased rates of uplift were observed by GPS stations in Kīlauea’s upper East Rift Zone. In the past month, increased uplift has also been measured at GPS stations in Kīlauea’s summit region. While uplift related to post-collapse inflation of the summit reservoir has been occurring since March of 2019, rates have been steadily increasing in recent months and are currently higher than they have been since the end of the 2018 eruption.

In late November 2020, increased earthquake rates began when seismic stations recorded an average of at least 480 shallow, small-magnitude earthquakes (97% of which were less than or equal to magnitude-2) per week occurring at depths of less than 4 km (2.5 miles) beneath Kīlauea's summit and upper East Rift Zone. This compares to a rate of fewer than 180 per week following the end of Kīlauea’s 2018 eruption and through early November 2020.

On December 2, 2020, GPS stations and tiltmeters recorded a ground deformation event at Kīlauea’s summit. Accompanied by earthquake swarms, the patterns of ground deformation observed were consistent with a small dike intrusion of magma under the southern part of Kīlauea caldera. The injection resulted in about 8 cm (3 inches) of uplift of the caldera floor, and modeling suggests that it represented 0.4–0.7 million cubic meters (yards) of magma accumulated approximately 1.5 km (1 mile) beneath the surface. Though the intrusion did not reach the surface and erupt, it represented a notable excursion from trends observed in Kīlauea summit monitoring data streams following the end of the 2018 eruption.

On December 17, 2020, seismometers detected a notable increase in occurrence and duration of long-period seismic signals beneath Kīlauea’s summit, which are attributed to magmatic activity. Whereas this type of seismicity was observed on average once every few weeks following the 2018 eruption, rates have increased to over a dozen in the past several days.

Other monitoring data streams including volcanic gas and webcam imagery were stable until this eruption.

An earthquake swarm began on the evening of December 20, accompanied by ground deformation detected by tiltmeters. An orange glow was subsequently observed on IR monitoring cameras and visually beginning approximately 21:36 HST.
(12) Volcanic cloud height: unknown
(13) Other volcanic cloud information: unknown
(14) Remarks: Hazard Analysis:

HVO is currently assessing the hazards associated with this eruption and will provide updates as information becomes known.

At the present time, no explosions have been detected.

For discussion of Kīlauea hazards, please see:

https://www.usgs.gov/observatories/hawaiian-volcano-observatory/hazards and

https://www.usgs.gov/volcanoes/kilauea/frequently-asked-questions-about-k-lauea-volcanos-summit-water

Remarks:

Background

Since the early 1800s, when written records of Hawaiian volcanoes began, Kīlauea has had infrequent periods during which no lava erupted.

The longest known eruptive pause was in 1935-1952, ending with eruption in the caldera. Neither that 17-year pause, nor any other shorter pause, followed partial collapse of the caldera such as the collapse that occurred in the summer of 2018.

Following partial caldera collapses, the first eruption outside the caldera took place on the East Rift Zone 17 years after the 1823 collapse, on the Southwest Rift Zone 28 years after the 1840 collapse, and on the Southwest Rift Zone 52 years after the 1868 collapse.

After partial caldera collapses in 1840 and 1868, lava returned to the caldera within days to a few weeks. The length of the current pause exceeds those earlier post-collapse pauses.

Kīlauea Volcano has maintained a low level of non-eruptive unrest since the end of the 2018 lower East Rift Zone eruption and summit collapse, which deepened Halemaʻumaʻu crater by over 500 meters (1640 feet). Following the 2018 eruption, ground deformation rates have indicated steady inflation of Kīlauea’s summit and at the end of 2018, the HVO monitoring network detected Deflation-Inflation events (DI-events) indicative that the shallow Halemaʻumaʻu magma reservoir, located approximately 1.6 km (1 mile) under Kīlauea caldera, still contained significant amounts of magma.

In late July 2019, ponded water appeared at the base of the deepest collapsed area of Kīlauea’s summit, within the Halemaʻumaʻu crater. Since then, the body of water has grown into a lake, which continues to rise as it seeks equilibrium with the surrounding groundwater.


Prognosis

All communities on or near Kīlauea’s summit and rift zones should be prepared.

HVO continues to monitor the volcano closely and will report any significant changes. HVO is in close touch with National Park Service and Hawaii County Civil Defense and other agencies responsible for public safety.

Stay informed about Kīlauea by following volcano updates and tracking current monitoring data on the HVO web page (https://www.usgs.gov/volcanoes/kilauea/volcano-updates) or by signing up to receive updates by email at this site: https://volcanoes.usgs.gov/vns2/.

The County of Hawai‘i Civil Defense Agency is in constant communications with HVO. If anything develops that may affect your safety, you will be informed. Please sign up for Civil Defense notifications by visiting the County of Hawai‘i Civil Defense Agency webpage at http://www.hawaiicounty.gov/civil-defense/.


Contacts: askHVO@usgs.gov
(15) Contacts: askHVO@usgs.gov
(16) Next Notice: The Hawaiian Volcano Observatory (HVO) continues to closely monitor Kīlauea's seismicity, deformation, and gas emissions for any sign of reactivation. HVO will continue to issue weekly Kīlauea updates on Tuesdays until further notice.
2020-12-03 - Korovin, Aviation Color Code: GREEN (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20201203/2017Z)
(3) Volcano: Korovin (VNUM #311161)
(4) Current Color Code: GREEN
(5) Previous Color Code: YELLOW
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2020/A1279
(8) Volcano Location: N 52 deg 22 min W 174 deg 9 min
(9) Area: Aleutians
(10) Summit Elevation: 5030 ft (1533 m)
(11) Volcanic Activity Summary: Unrest at Korvin Volcano that began in late October 2020 has subsided. Seismic activity has returned to background levels and satellite observations over the past several weeks have shown no signs of unrest. Thus, AVO is decreasing the Aviation Color Code and Alert Level to GREEN/NORMAL.

Korovin is monitored by local seismic and infrasound sensors, satellite data, regional lightning detection instruments, and reports from local residents. Observations of steaming are not unusual at Korovin and meteorological conditions can enhance its visibility.
(12) Volcanic cloud height: n/a
(13) Other volcanic cloud information: steam from the summit crater is common
(14) Remarks: Korovin Volcano is a 1553-m-high (5030 ft) stratovolcano located on the northern part of Atka Island in the central Aleutian Islands, about 21 km (13 mi) northwest of the community of Atka, 538 km (350 mi) west of Dutch Harbor, and 1760 km (1100 mi) southwest of Anchorage. The volcano has two distinct summit vents about 0.6 km (2000 ft) apart, that have been the sites of eruptive activity in historical time. The most recently active of the vents maintains a small, roiling, lake that occasionally produces energetic steam emissions. Thermal springs and fumaroles located on and near the volcano indicate an active hydrothermal system. Korovin has erupted several times in the past 200 years, including 1973, 1987, and 1998, and has likely had small ash emissions as recently as 2005. Typical recent Korovin eruptions produce minor amounts of ash and occasional but small lava flows. Reports of the height of the ash plume produced by the 1998 eruption ranged from 4900 to 10,600 m (16,000 to 35,000 feet) above sea level.
(15) Contacts:
Matt Haney, Acting Scientist-in-Charge, USGS
mhaney@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI
dfee1@alaska.edu (907) 322-4085
(16) Next Notice:
2020-11-20 - Semisopochnoi, Aviation Color Code: UNASSIGNED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20201120/1900Z)
(3) Volcano: Semisopochnoi (VNUM #311060)
(4) Current Color Code: UNASSIGNED
(5) Previous Color Code: YELLOW
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2020/A1265
(8) Volcano Location: N 51 deg 55 min E 179 deg 35 min
(9) Area: Aleutians
(10) Summit Elevation: 2625 ft (800 m)
(11) Volcanic Activity Summary: No eruptive activity has been detected at Semisopochnoi since mid-June. Seismicity has persisted above background levels since that time, but had decreased to very low levels before a satellite link for transmitting seismic data failed on November 11, 2020. Since that time, no changes have been observed in satellite data, and no explosions have been detected from the Adak Island infrasound array. AVO is lowering the Aviation Color Code to UNASSIGNED and Alert Level to UNASSIGNED for Semisopochnoi due to the lack of evidence for ongoing unrest. Low-level seismic unrest may be continuing undetected. The satellite link is not likely to be reestablished without a site visit.

Despite the lack of eruptive activity since mid-June, Semisopochnoi has been in a state of unrest since September 2018, producing sporadic low-level explosions and elevated seismicity. Future small explosions may occur without warning and typically generate small clouds of volcanic ash that are a hazard in the immediate vicinity of the erupting vent at North Cerberus. More significant ash emissions may be possible, but have not been observed during the 2018–2020 eruptive period.
(12) Volcanic cloud height: n/a
(13) Other volcanic cloud information: n/a
(14) Remarks: The seismic monitoring network for Semisopochnoi has been offline since November 11, but if atmospheric conditions permit an infrasound array on Adak Island may detect explosion signals from Semisopochnoi with a 13 minute delay. Semisopochnoi is also monitored remotely with satellite observations and lightning sensors.
(15) Contacts: Matt Haney, Acting Scientist-in-Charge, USGS
mhaney@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI
dfee1@alaska.edu (907) 322-4085
(16) Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at http://www.avo.alaska.edu
2020-10-28 - Korovin, Aviation Color Code: YELLOW (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20201028/1751Z)
(3) Volcano: Korovin (VNUM #311161)
(4) Current Color Code: YELLOW
(5) Previous Color Code: GREEN
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 52 deg 22 min W 174 deg 9 min
(9) Area: Aleutians
(10) Summit Elevation: 5030 ft (1533 m)
(11) Volcanic Activity Summary: Based on recent satellite detections of significant sulfur dioxide emissions and an increase in seismicity to a level above background, AVO is raising the Aviation Color Code and Alert Level at Korovin Volcano to YELLOW/ADVISORY. Discrete earthquakes have been detected over the past two weeks and sulfur dioxide degassing has been detected four times in satellite data on October 15, 20 and 26. Clear satellite views show no other signs of activity at this time. AVO will continue to monitor the volcano for signs of volcanic activity.

Korovin is monitored by local seismic and infrasound sensors, satellite data, and regional lightning detection instruments.
(12) Volcanic cloud height: n/a
(13) Other volcanic cloud information: sulfur dioxide emissions detected in satellite data.
(14) Remarks: Korovin Volcano is a 1553-m-high (5030 ft) stratovolcano located on the northern part of Atka Island in the central Aleutian Islands, about 21 km (13 mi) northwest of the community of Atka, 538 km (350 mi) west of Dutch Harbor, and 1760 km (1100 mi) southwest of Anchorage. The volcano has two distinct summit vents about 0.6 km (2000 ft) apart, that have been the sites of eruptive activity in historical time. The most recently active of the vents maintains a small, roiling, lake that occasionally produces energetic steam emissions. Thermal springs and fumaroles located on and near the volcano indicate an active hydrothermal system. Korovin has erupted several times in the past 200 years, including 1973, 1987, and 1998, and has likely had small ash emissions as recently as 2005. Typical recent Korovin eruptions produce minor amounts of ash and occasional but small lava flows. Reports of the height of the ash plume produced by the 1998 eruption ranged from 4900 to 10,600 m (16,000 to 35,000 feet) above sea level.
(15) Contacts: Matt Haney, Acting Scientist-in-Charge, USGS
mhaney@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI
dfee1@alaska.edu (907) 322-4085
(16) Next Notice:
2020-10-21 - Great Sitkin, Aviation Color Code: GREEN (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20201021/2321Z)
(3) Volcano: Great Sitkin (VNUM #311120)
(4) Current Color Code: GREEN
(5) Previous Color Code: YELLOW
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 52 deg 4 min W 176 deg 6 min
(9) Area: Aleutians
(10) Summit Elevation: 5709 ft (1740 m)
(11) Volcanic Activity Summary: Seismicity at Great Sitkin has been steadily decreasing for the past several months and is now at background levels. No eruptive activity or unusual surface temperatures have been observed in clear satellite imagery. The Alaska Volcano Observatory is returning the Aviation Color Code and Alert Level to GREEN/NORMAL to reflect these background conditions. AVO will continue to monitor the volcano using seismic, infrasound, web camera, and satellite observations.

Great Sitkin is monitored with a local real-time seismic network, which will typically allow AVO to detect changes in unrest that may lead to an explosive eruption. Rapid detection of an ash-producing eruption would be accomplished using a combination of seismic, infrasound, lightning, and satellite data.
(12) Volcanic cloud height: n/a
(13) Other volcanic cloud information: n/a
(14) Remarks: Great Sitkin Volcano is a basaltic andesite volcano that occupies most of the northern half of Great Sitkin Island, a member of the Andreanof Islands group in the central Aleutian Islands. It is located 43 km (26 miles) east of the community of Adak. The volcano is a composite structure consisting of an older dissected volcano and a younger parasitic cone with a 3-km-diameter summit crater. A steep-sided lava dome, emplaced during an eruption in 1974, occupies the center of the crater. Great Sitkin erupted at least three times in the 20th century, most recently in 1974. That eruption produced at least one ash cloud that likely exceeded an altitude of 25,000 ft above sea level. A poorly documented eruption occurred in 1945, also producing a lava dome that was partially destroyed in the 1974 eruption. Within the past 280 years a large explosive eruption produced pyroclastic flows that partially filled the Glacier Creek valley on the southwest flank.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI
dfee1@alaska.edu (907) 322-4085
(16) Next Notice:
2020-10-15 - Westdahl, Aviation Color Code: GREEN (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20201015/2025Z)
(3) Volcano: Westdahl (VNUM #311340)
(4) Current Color Code: GREEN
(5) Previous Color Code: UNASSIGNED
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 54 deg 31 min W 164 deg 38 min
(9) Area: Aleutians
(10) Summit Elevation: 5118 ft (1560 m)
(11) Volcanic Activity Summary: The Alaska Volcano Observatory (AVO) has reestablished seismic monitoring instruments at Westdahl volcano and can now confidently monitor seismic unrest at the volcano. With renewed seismic monitoring, the volcano moves from UNASSIGNED to Volcano Alert Level NORMAL and Aviation Color Code GREEN. As at other Alaska volcanoes, AVO will continue to monitor seismic, satellite, infrasound, and lightning data, and reports from pilots and ground observers to detect signs of eruptive activity.
(12) Volcanic cloud height: n/a
(13) Other volcanic cloud information: n/a
(14) Remarks:
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI
dfee1@alaska.edu (907) 322-4085
(16) Next Notice:
2020-10-14 - Pavlof, Aviation Color Code: GREEN (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20201014/1754Z)
(3) Volcano: Pavlof (VNUM #312030)
(4) Current Color Code: GREEN
(5) Previous Color Code: YELLOW
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 55 deg 25 min W 161 deg 53 min
(9) Area: Alaska Peninsula
(10) Summit Elevation: 8261 ft (2518 m)
(11) Volcanic Activity Summary: The periods of seismic tremor that prompted an increase in Pavlof's alert level on September 21 have not been observed in the last two weeks. No eruptive activity or unusual surface temperatures have been observed in clear satellite and web camera images. The Alaska Volcano Observatory is returning the Aviation Color Code and Alert Level to GREEN/NORMAL to reflect these background conditions. Eruptions at Pavlof often occur with little or no precursory activity, and AVO will continue to monitor the volcano using seismic, infrasound, web camera, and satellite observations.
(12) Volcanic cloud height: None
(13) Other volcanic cloud information: None
(14) Remarks: Pavlof Volcano is a snow- and ice-covered stratovolcano located on the southwestern end of the Alaska Peninsula about 953 km (592 mi) southwest of Anchorage. The volcano is about 7 km (4.4 mi) in diameter and has active vents on the north and east sides close to the summit. With over 40 historic eruptions, it is one of the most consistently active volcanoes in the Aleutian arc. Eruptive activity is generally characterized by sporadic Strombolian lava fountaining continuing for a several-month period. Ash plumes as high as 49,000 ft ASL have been generated by past eruptions of Pavlof, and during the March 2016 eruption, ash plumes as high as 40,000 feet above sea level were generated and the ash was tracked in satellite data as distant as eastern Canada. The nearest community, Cold Bay, is located 60 km (37 miles) to the southwest of Pavlof.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI
dfee1@alaska.edu (907) 322-4085
(16) Next Notice:
2020-09-21 - Pavlof, Aviation Color Code: YELLOW (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20200921/2249Z)
(3) Volcano: Pavlof (VNUM #312030)
(4) Current Color Code: YELLOW
(5) Previous Color Code: GREEN
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 55 deg 25 min W 161 deg 53 min
(9) Area: Alaska Peninsula
(10) Summit Elevation: 8261 ft (2518 m)
(11) Volcanic Activity Summary: Seismic activity has increased at Pavlof over the past 24 hours and is characterized by ongoing tremor. No eruptive activity or emissions from the summit have been observed in cloudy satellite and web camera views. However, the seismic activity represents an increase from background levels and we are thus increasing the the Aviation Color Code and Alert Level to YELLOW/ADVISORY. This does not mean that an eruption is likely or imminent. However, past eruptions of Pavlof occurred with little or no warning.
(12) Volcanic cloud height: None
(13) Other volcanic cloud information: None
(14) Remarks: Pavlof Volcano is a snow- and ice-covered stratovolcano located on the southwestern end of the Alaska Peninsula about 953 km (592 mi) southwest of Anchorage. The volcano is about 7 km (4.4 mi) in diameter and has active vents on the north and east sides close to the summit. With over 40 historic eruptions, it is one of the most consistently active volcanoes in the Aleutian arc. Eruptive activity is generally characterized by sporadic Strombolian lava fountaining continuing for a several-month period. Ash plumes as high as 49,000 ft ASL have been generated by past eruptions of Pavlof, and during the March 2016 eruption, ash plumes as high as 40,000 feet above sea level were generated and the ash was tracked in satellite data as distant as eastern Canada. The nearest community, Cold Bay, is located 60 km (37 miles) to the southwest of Pavlof.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI
dfee1@alaska.edu (907) 322-4085
(16) Next Notice:
2020-09-08 - Makushin, Aviation Color Code: GREEN (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20200908/2152Z)
(3) Volcano: Makushin (VNUM #311310)
(4) Current Color Code: GREEN
(5) Previous Color Code: YELLOW
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 53 deg 53 min W 166 deg 55 min
(9) Area: Aleutians
(10) Summit Elevation: 5906 ft (1800 m)
(11) Volcanic Activity Summary: Seismicity at Makushin Volcano has been steadily declining for months, following an earthquake sequence that began on June 15, 2020. This earthquake sequence was focused within an area about 6 miles (10 km) east of the summit at a depth of about 5 miles (8 km). Current observations indicate seismic activity has returned to background levels, and thus the Aviation Color Code and the Volcano Alert Level are being decreased to GREEN/NORMAL. Other data streams showed no signs of surface changes during the seismic sequence that started in June. The volcano is monitored with a network of seismic instruments, web camera, GPS, satellite data, and regional infrasound and lightning detection instruments.
(12) Volcanic cloud height: n/a
(13) Other volcanic cloud information: n/a
(14) Remarks: Makushin volcano is located on northern Unalaska Island in the eastern Aleutian Islands. Makushin is a broad, ice-capped stratovolcano which rises to an elevation of 6680 feet. The summit caldera, 3 km diameter, is the site of frequent steam and minor ash eruptions; however, no large eruptions have occurred in this century. The community of Unalaska and port of Dutch Harbor are located 25 km (16 miles) east of Makushin volcano.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI
dfee1@alaska.edu (907) 322-4085
(16) Next Notice:
2020-09-03 - Cleveland, Aviation Color Code: UNASSIGNED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20200903/0140Z)
(3) Volcano: Cleveland (VNUM #311240)
(4) Current Color Code: UNASSIGNED
(5) Previous Color Code: YELLOW
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 52 deg 49 min W 169 deg 56 min
(9) Area: Aleutians
(10) Summit Elevation: 5676 ft (1730 m)
(11) Volcanic Activity Summary: A sustained pause in volcanic unrest at Cleveland Volcano over the last few months has prompted the Alaska Volcano Observatory to downgrade the Aviation Color Code and Volcano Alert Level from YELLOW/ADVISORY to UNASSIGNED/UNASSIGNED.

The last eruptive activity at Cleveland Volcano was a short-lived explosion on the evening (local time) of June 1, 2020. Since then, there has been no evidence from satellite observations of elevated surface temperatures, and there have been no observed changes in the summit crater.

Despite the current pause, the eruptive period at Cleveland, dating back to 2001, remains ongoing and future explosions are likely. These occur without warning and typically generate small clouds of volcanic ash that are a hazard in the immediate vicinity of the volcano, though more significant ash emissions are possible.
(12) Volcanic cloud height: none
(13) Other volcanic cloud information: n/a
(14) Remarks: Cleveland Volcano is monitored with a limited real-time seismic network. This smaller network inhibits AVO's ability to detect precursory unrest that may lead to an explosive eruption, which results in it being designated as UNASSIGNED instead of the color code GREEN assigned to quiescent volcanoes with more instrumentation. Rapid detection of an ash-producing eruption may be possible using a combination of seismic, infrasound, lightning, and satellite data.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI
dfee1@alaska.edu (907) 322-4085
(16) Next Notice:
2020-08-20 - Veniaminof, Aviation Color Code: GREEN (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20200820/1939Z)
(3) Volcano: Veniaminof (VNUM #312070)
(4) Current Color Code: GREEN
(5) Previous Color Code: YELLOW
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 56 deg 11 min W 159 deg 23 min
(9) Area: Alaska Peninsula
(10) Summit Elevation: 8225 ft (2507 m)
(11) Volcanic Activity Summary: Seismic tremor detected in June at Veniaminof has continued intermittently, but with decreasing frequency, and there have been no indications of surface change including increased temperatures or gas emissions. Tremor at Veniaminof in the past has sometimes preceded eruptions, but also can occur and persist for weeks to months and not result in an eruption. Current observations suggest activity has returned to near background, and thus the Aviation Color Code and the Volcano Alert Level are being decreased to GREEN/NORMAL.

The Alaska Volcano Observatory continues to closely monitor Veniaminof with local seismic sensors, satellite data, web cameras, and remote infrasound and lightning networks.
(12) Volcanic cloud height: None
(13) Other volcanic cloud information: n/a
(14) Remarks: Mount Veniaminof volcano is an andesitic stratovolcano with an ice-filled 10-km diameter summit caldera located on the Alaska Peninsula, 775 km (480 mi) southwest of Anchorage and 35 km (22 mi) north of Perryville. Veniaminof is one of the largest (~300 cubic km; 77 cubic mi) and most active volcanic centers in the Aleutian Arc and has erupted at least 14 times in the past 200 years. Recent eruptions in 1993-95, 2005, 2013, and 2018 all occurred at the intracaldera cone and lasted for several months. These eruptions produced lava spattering and fountaining, minor emissions of ash and gas, and small lava flows into intracaldera icefield. Minor ash-producing explosions occurred nearly annually between 2002 and 2010. Previous historical eruptions have produced ash plumes that reached 15,000 to 20,000 ft above sea level (1939, 1956, and 2018) and ash fallout that blanketed areas within about 40 km (25 mi) of the volcano (1939, 2018).
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Taryn Lopez, Acting Coordinating Scientist, UAFGI
tmlopez@alaska.edu (907) 322-4085
(16) Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at
http://www.avo.alaska.edu
2020-06-24 - Shishaldin, Aviation Color Code: GREEN (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20200624/2000Z)
(3) Volcano: Shishaldin (VNUM #311360)
(4) Current Color Code: GREEN
(5) Previous Color Code: YELLOW
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 54 deg 45 min W 163 deg 58 min
(9) Area: Aleutians
(10) Summit Elevation: 9373 ft (2857 m)
(11) Volcanic Activity Summary: Seismicity at Shishaldin Volcano has decreased to background levels. Satellite views over the past few weeks suggest typical background surface temperatures and light steaming at the summit and no signs of new volcanic activity within the crater. Due to this decrease in activity, the Alaska Volcano Observatory is decreasing the Aviation Color Code for Shishaldin Volcano to GREEN and the Alert Level to NORMAL.

This most recent eruptive cycle at Shishaldin began in July 2019 with pauses in activity in late September/early October 2019 and February 2020. The most recent activity in mid-March was confined to the summit crater except for minor ash deposits near the summit. Only minor rockfalls within the summit crater, not associated with eruptive activity, have been detected since early April. Pauses in eruptions are common at Shishaldin, and therefore eruptive activity could resume with little warning. The Alaska Volcano Observatory will continue to monitor the volcano closely.

Shishaldin is monitored by local seismic and infrasound sensors, satellite data, a web camera, a telemetered geodetic network, and distant infrasound and lightning networks.
(12) Volcanic cloud height: na
(13) Other volcanic cloud information: na
(14) Remarks: Shishaldin volcano, located near the center of Unimak Island in the eastern Aleutian Islands, is a spectacular symmetric cone with a base diameter of approximately 16 km (10 mi). A 200-m-wide (660 ft) funnel-shaped summit crater typically emits a steam plume and occasional small amounts of ash. Shishaldin is one of the most active volcanoes in the Aleutian volcanic arc, with at least 54 episodes of unrest including over 24 confirmed eruptions since 1775. Most eruptions are relatively small, although the April-May 1999 event generated an ash column that reached 45,000 ft above sea level.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Janet Schaefer, Acting Coordinating Scientist, ADGGS
janet.schaefer@alaska.gov (907) 322-4085
(16) Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at http://www.avo.alaska.edu
2020-06-18 - Veniaminof, Aviation Color Code: YELLOW (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20200618/2201Z)
(3) Volcano: Veniaminof (VNUM #312070)
(4) Current Color Code: YELLOW
(5) Previous Color Code: GREEN
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 56 deg 11 min W 159 deg 23 min
(9) Area: Alaska Peninsula
(10) Summit Elevation: 8225 ft (2507 m)
(11) Volcanic Activity Summary: Over the past several days there have been periods of seismic tremor and occasional earthquakes at Veniaminof. This represents a departure from background activity. Thus, the Aviation Color Code and the Volcano Alert Level are being increased to YELLOW/ADVISORY.

This type of seismic activity typically precedes eruptive activity at Veniaminof but does not mean that an eruption will occur. Eruptive activity usually consists of minor ash emissions, lava fountaining and lava flows from the small cone in the summit caldera. Ash emissions are typically confined to the summit crater, but larger events can result in ash fall in nearby communities and drifting airborne ash.

Veniaminof volcano is monitored by local seismic sensors, satellite data, web cameras, and remote infrasound and lightning networks.
(12) Volcanic cloud height: None
(13) Other volcanic cloud information: n/a
(14) Remarks: Mount Veniaminof volcano is an andesitic stratovolcano with an ice-filled 10-km diameter summit caldera located on the Alaska Peninsula, 775 km (480 mi) southwest of Anchorage and 35 km (22 mi) north of Perryville. Veniaminof is one of the largest (~300 cubic km; 77 cubic mi) and most active volcanic centers in the Aleutian Arc and has erupted at least 14 times in the past 200 years. Recent eruptions in 1993-95, 2005, 2013, and 2018 all occurred at the intracaldera cone and lasted for several months. These eruptions produced lava spattering and fountaining, minor emissions of ash and gas, and small lava flows into intracaldera icefield. Minor ash-producing explosions occurred nearly annually between 2002 and 2010. Previous historical eruptions have produced ash plumes that reached 15,000 to 20,000 ft above sea level (1939, 1956, and 2018) and ash fallout that blanketed areas within about 40 km (25 mi) of the volcano (1939, 2018).
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI
dfee1@alaska.edu (907) 322-4085

(16) Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at
http://www.avo.alaska.edu
2020-06-17 - Cleveland, Aviation Color Code: YELLOW (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20200617/1956Z)
(3) Volcano: Cleveland (VNUM #311240)
(4) Current Color Code: YELLOW
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 52 deg 49 min W 169 deg 56 min
(9) Area: Aleutians
(10) Summit Elevation: 5676 ft (1730 m)
(11) Volcanic Activity Summary: There has been no sign of eruptive activity at Cleveland volcano since a short-lived explosion on the evening (local time) of June 1, 2020. Thus, the Aviation Color Code and Volcano Alert Level are being reduced to YELLOW/ADVISORY.

Cleveland is almost always in a state of unrest and explosions will occur without warning. They typically generate small clouds of volcanic ash that are a hazard in the immediate vicinity of the volcano. Ash fall on the upper flanks of the volcano is also common. Flows of mud and/or hot hot rock are generated in the drainages during some of these explosive events and can extend all the way to coast.

The local geophysical stations and web camera at Cleveland are currently unavailable due to an ongoing network outage. Rapid detection of an ash-producing eruption may be possible using a combination of regional infrasound, lightning, and satellite data.
(12) Volcanic cloud height: none
(13) Other volcanic cloud information: n/a
(14) Remarks:
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI
dfee1@alaska.edu (907) 322-4085

(16) Next Notice:
2020-06-16 - Makushin, Aviation Color Code: YELLOW (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20200616/0202Z)
(3) Volcano: Makushin (VNUM #311310)
(4) Current Color Code: YELLOW
(5) Previous Color Code:
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 53 deg 53 min W 166 deg 55 min
(9) Area: Aleutians
(10) Summit Elevation: 5906 ft (1800 m)
(11) Volcanic Activity Summary: Over the past several hours, there have been two earthquakes larger than magnitude 4 in the vicinity of Makushin Volcano. This represents a significant departure from background earthquake activity and may be associated with volcanic unrest. As a result the Aviation Color Code and Volcano Alert Level has been increased to YELLOW/ADVISORY. This unrest could result a future eruption, however that is not a certainty. Aftershocks continue, as would be expected with earthquakes of this size. The volcano is monitored with a network of seismic instruments, web camera, GPS, satellite data, and regional infrasound and lightning detection instruments.
(12) Volcanic cloud height: No cloud produced.
(13) Other volcanic cloud information: n/a
(14) Remarks: Makushin volcano is located on northern Unalaska Island in the eastern Aleutian Islands. Makushin is a broad, ice-capped stratovolcano which rises to an elevation of 6680 feet. The summit caldera, 3 km diameter, is the site of frequent steam and minor ash eruptions; however, no large eruptions have occurred in this century. The community of Unalaska and port of Dutch Harbor are located 25 km (16 miles) east of Makushin volcano.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI
dfee1@alaska.edu (907) 322-4085

(16) Next Notice:
2020-06-02 - Cleveland, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20200602/0746Z)
(3) Volcano: Cleveland (VNUM #311240)
(4) Current Color Code: ORANGE
(5) Previous Color Code: UNASSIGNED
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 52 deg 49 min W 169 deg 56 min
(9) Area: Aleutians
(10) Summit Elevation: 5676 ft (1730 m)
(11) Volcanic Activity Summary: Regional infrasound sensors recorded a small explosion today at about 06:32 UTC (10:32 AKST). No other significant activity was detected and local monitoring stations are offline. A small ash plume was observed at 22,000 ft drifting to the south.

Explosions from Cleveland typically produce relatively small volcanic ash clouds that dissipate within hours; however, more significant ash emissions are possible.

Cleveland volcano is monitored with a limited real-time seismic network, which inhibits AVO's ability to detect precursory unrest that may lead to an explosive eruption. Rapid detection of an ash-producing eruption may be possible using a combination of seismic, infrasound, lightning, and satellite data.
(12) Volcanic cloud height: 22,000 ft
(13) Other volcanic cloud information: Drifting to the south
(14) Remarks:
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI
dfee1@alaska.edu (907) 322-4085

(16) Next Notice:
2020-05-07 - Cleveland, Aviation Color Code: UNASSIGNED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20200507/2337Z)
(3) Volcano: Cleveland (VNUM #311240)
(4) Current Color Code: UNASSIGNED
(5) Previous Color Code: YELLOW
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 52 deg 49 min W 169 deg 56 min
(9) Area: Aleutians
(10) Summit Elevation: 5676 ft (1730 m)
(11) Volcanic Activity Summary: A sustained decline in volcanic unrest at Cleveland Volcano over the last several months has prompted the Alaska Volcano Observatory to downgrade the Aviation Color Code and Volcano Alert Level from YELLOW/ADVISORY to UNASSIGNED/UNASSIGNED.

The last explosive eruption at Cleveland occurred on January 9, 2019, and was followed by the extrusion of a small mound of lava in the summit crater. Since then, there has been an overall decrease in detected surface temperature and no observed changes in the summit crater.

Cleveland is one of the most active volcanoes of the Aleutian Arc, and the latest eruptive phase has waxed and waned almost annually since 2001. Local seismic, infrasound, and web camera data have been mostly unavailable for several weeks due to an equipment failure in a remote facility. Nonetheless, monitoring of Cleveland continues with regional seismic and infrasound stations on nearby islands. These, along with lightning and satellite data, should allow AVO to detect an ash-producing eruption, if one were to occur.
(12) Volcanic cloud height: None
(13) Other volcanic cloud information: n/a
(14) Remarks:
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI
dfee1@alaska.edu (907) 322-4085
(16) Next Notice:
2020-04-16 - Shishaldin, Aviation Color Code: YELLOW (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20200416/1944Z)
(3) Volcano: Shishaldin (VNUM #311360)
(4) Current Color Code: YELLOW
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 54 deg 45 min W 163 deg 58 min
(9) Area: Aleutians
(10) Summit Elevation: 9373 ft (2857 m)
(11) Volcanic Activity Summary: Seismicity at Shishaldin Volcano has decreased over the past two weeks to levels slightly above background. Similarly, satellite views show no lava or changes within the crater since the start of April, accompanied by a decrease in surface temperatures. Eruptive activity therefore appears to have ended or paused. Due to this decrease in activity, the Alaska Volcano Observatory is decreasing the Aviation Color Code for Shishaldin Volcano to YELLOW and the Alert Level to ADVISORY.

Eruptive activity at Shishaldin paused after the explosion on January 19, 2020, before resuming at a low level mid-March. It is therefore possible for eruptive activity to resume with little warning and AVO will continue to monitor the volcano closely.

Shishaldin is monitored by local seismic and infrasound sensors, satellite data, a web camera, a telemetered geodetic network, and distant infrasound and lightning networks.
(12) Volcanic cloud height: na
(13) Other volcanic cloud information: na
(14) Remarks: Shishaldin volcano, located near the center of Unimak Island in the eastern Aleutian Islands, is a spectacular symmetric cone with a base diameter of approximately 16 km (10 mi). A 200-m-wide (660 ft) funnel-shaped summit crater typically emits a steam plume and occasional small amounts of ash. Shishaldin is one of the most active volcanoes in the Aleutian volcanic arc, with at least 54 episodes of unrest including over 24 confirmed eruptions since 1775. Most eruptions are relatively small, although the April-May 1999 event generated an ash column that reached 45,000 ft above sea level.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI
dfee1@alaska.edu (907) 322-4085
(16) Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at http://www.avo.alaska.edu
2020-04-01 - Semisopochnoi, Aviation Color Code: YELLOW (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20200401/2016Z)
(3) Volcano: Semisopochnoi (VNUM #311060)
(4) Current Color Code: YELLOW
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 51 deg 55 min E 179 deg 35 min
(9) Area: Aleutians
(10) Summit Elevation: 2625 ft (800 m)
(11) Volcanic Activity Summary: Seismic, infrasound, and satellite data over the past two weeks have shown no signs of eruptive activity at Semisopochnoi. A robust steam plume and a crater lake have been seen in clear satellite images, but no recent ash deposits. Although seismic activity remains above background, it does not appear to be increasing towards an eruption in the short-term. Thus, AVO is reducing the Aviation Color Code to YELLOW and the Volcano Alert Level to ADVISORY. Unrest continues. Seismic activity persists and is characterized by occasional small earthquakes and satellite data show detectable volcanic gas (sulfur dioxide) being emitted from the volcano. Explosive activity could resume with little to no warning.
(12) Volcanic cloud height: n/a
(13) Other volcanic cloud information: n/a
(14) Remarks: Semisopochnoi is monitored with an on-island seismic network, and remotely by satellite and lightning sensors. An infrasound array on Adak Island could detect explosive emissions from Semisopochnoi with a 13 minute delay if atmospheric conditions permit.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI
dfee1@alaska.edu (907) 322-4085
(16) Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at http://www.avo.alaska.edu
2020-03-16 - Semisopochnoi, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20200316/0124Z)
(3) Volcano: Semisopochnoi (VNUM #311060)
(4) Current Color Code: ORANGE
(5) Previous Color Code: YELLOW
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 51 deg 55 min E 179 deg 35 min
(9) Area: Aleutians
(10) Summit Elevation: 2625 ft (800 m)
(11) Volcanic Activity Summary: Seismicity has been increasing the last few days at Semisopochnoi, and now is characterized by nearly continuous tremor and frequent small explosion signals. This represents a significant increase in activity and the Alaska Volcano Observatory is increasing the Aviation Color Code to ORANGE and the Volcano Alert Level to WATCH. No significant ash emissions have been detected in satellite images; clouds cover much of the island to around 10,000 ft. asl.
(12) Volcanic cloud height: n/a
(13) Other volcanic cloud information: n/a
(14) Remarks: Semisopochnoi is monitored with an on-island seismic network, and remotely by satellite and lightning sensors. An infrasound array on Adak Island could detect explosive emissions from Semisopochnoi with a 13 minute delay if atmospheric conditions permit.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI
dfee1@alaska.edu (907) 322-4085
(16) Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at http://www.avo.alaska.edu
2020-03-15 - Shishaldin, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20200315/0631Z)
(3) Volcano: Shishaldin (VNUM #311360)
(4) Current Color Code: ORANGE
(5) Previous Color Code: YELLOW
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 54 deg 45 min W 163 deg 58 min
(9) Area: Aleutians
(10) Summit Elevation: 9373 ft (2857 m)
(11) Volcanic Activity Summary: A high-resolution satellite image today shows lava and what appears to be a new cone within the Shishaldin summit crater. Weak seismic tremor has also been detected. Therefore the Aviation Color Code for Shishaldin Volcano is being raised to ORANGE and the Alert Level to WATCH.

No significant ash or lava signatures are apparent outside the summit crater at this time. Eruptive activity could increase with little or no warning resulting in lava flows outside of the crater, lahars, and low-level ash clouds. During the current eruptive cycle, larger ash clouds have also been produced.

Shishaldin is monitored by local seismic and infrasound sensors, satellite data, a web camera, a telemetered geodetic network, and distant infrasound and lightning networks.
(12) Volcanic cloud height: na
(13) Other volcanic cloud information: na
(14) Remarks: Shishaldin volcano, located near the center of Unimak Island in the eastern Aleutian Islands, is a spectacular symmetric cone with a base diameter of approximately 16 km (10 mi). A 200-m-wide (660 ft) funnel-shaped summit crater typically emits a steam plume and occasional small amounts of ash. Shishaldin is one of the most active volcanoes in the Aleutian volcanic arc, with at least 54 episodes of unrest including over 24 confirmed eruptions since 1775. Most eruptions are relatively small, although the April-May 1999 event generated an ash column that reached 45,000 ft above sea level.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI
dfee1@alaska.edu (907) 322-4085
(16) Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at http://www.avo.alaska.edu
2020-03-03 - Pavlof, Aviation Color Code: GREEN (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20200303/1938Z)
(3) Volcano: Pavlof (VNUM #312030)
(4) Current Color Code: GREEN
(5) Previous Color Code: YELLOW
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 55 deg 25 min W 161 deg 53 min
(9) Area: Alaska Peninsula
(10) Summit Elevation: 8261 ft (2518 m)
(11) Volcanic Activity Summary: Over the past several weeks seismic activity has decreased at Pavlof. No eruptive activity or emissions from the summit have been observed since minor steam emissions in late February. Since activity is now at background levels, we are decreasing the Aviation Color Code and Alert Level to GREEN/NORMAL.
(12) Volcanic cloud height: None
(13) Other volcanic cloud information: None
(14) Remarks: Pavlof Volcano is a snow- and ice-covered stratovolcano located on the southwestern end of the Alaska Peninsula about 953 km (592 mi) southwest of Anchorage. The volcano is about 7 km (4.4 mi) in diameter and has active vents on the north and east sides close to the summit. With over 40 historic eruptions, it is one of the most consistently active volcanoes in the Aleutian arc. Eruptive activity is generally characterized by sporadic Strombolian lava fountaining continuing for a several-month period. Ash plumes as high as 49,000 ft ASL have been generated by past eruptions of Pavlof, and during the March 2016 eruption, ash plumes as high as 40,000 feet above sea level were generated and the ash was tracked in satellite data as distant as eastern Canada. The nearest community, Cold Bay, is located 60 km (37 miles) to the southwest of Pavlof.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI
dfee1@alaska.edu (907) 322-4085
(16) Next Notice:
2020-02-26 - Westdahl, Aviation Color Code: UNASSIGNED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20200226/2100Z)
(3) Volcano: Westdahl (VNUM #311340)
(4) Current Color Code: UNASSIGNED
(5) Previous Color Code:
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 54 deg 31 min W 164 deg 38 min
(9) Area: Aleutians
(10) Summit Elevation: 5118 ft (1560 m)
(11) Volcanic Activity Summary: Over the past several weeks the real-time seismic data stream at Westdahl volcano has ceased due to equipment problems in the field. Repairs are not feasible during the winter months. Without seismic data AVO cannot verify that the volcano is at its normal background state. Thus, the Aviation Color Code and Volcano Alert Levels are now UNASSIGNED.

Planned field work in April and during the summer will reestablish and improve the seismic monitoring network. At this time, rapid detection of an eruption (if one were to occur) may be possible using a combination of distant seismic and infrasound networks, lightning, and satellite data.
(12) Volcanic cloud height: n/a
(13) Other volcanic cloud information: n/a
(14) Remarks:
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI
dfee1@alaska.edu (907) 322-4085
(16) Next Notice:
2020-02-26 - Semisopochnoi, Aviation Color Code: YELLOW (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20200226/2059Z)
(3) Volcano: Semisopochnoi (VNUM #311060)
(4) Current Color Code: YELLOW
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 51 deg 55 min E 179 deg 35 min
(9) Area: Aleutians
(10) Summit Elevation: 2625 ft (800 m)
(11) Volcanic Activity Summary: High-resolution satellite data from yesterday afternoon shows no signs of eruptive activity or recent ash deposits at Semisopochnoi. Although seismic activity remains above background, it does not appear to be increasing towards an eruption in the short-term. Thus, AVO is reducing the Aviation Color Code to YELLOW and the Volcano Alert Level to ADVISORY.

Unrest continues. Seismic activity persists and is characterized by short bursts of volcanic tremor and earthquakes. Explosive activity could resume with little to no warning.
(12) Volcanic cloud height: n/a
(13) Other volcanic cloud information: n/a
(14) Remarks: Semisopochnoi is monitored with an on-island seismic network, and remotely by satellite and lightning sensors. An infrasound array on Adak Island could detect explosive emissions from Semisopochnoi with a 13 minute delay if atmospheric conditions permit.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI
dfee1@alaska.edu (907) 322-4085
(16) Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at http://www.avo.alaska.edu
2020-02-26 - Great Sitkin, Aviation Color Code: YELLOW (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20200226/2058Z)
(3) Volcano: Great Sitkin (VNUM #311120)
(4) Current Color Code: YELLOW
(5) Previous Color Code: GREEN
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 52 deg 4 min W 176 deg 6 min
(9) Area: Aleutians
(10) Summit Elevation: 5709 ft (1740 m)
(11) Volcanic Activity Summary: Over the past month, earthquake activity has increased at Great Sitkin Volcano and is now above background levels. Thus, AVO is increasing the Aviation Color Code to YELLOW and the Alert Level to ADVISORY. There has been no evidence of eruptive activity in geophysical data streams or in satellite observations.

Great Sitkin is monitored with a local real-time seismic network, which will typically allow AVO to detect changes in unrest that may lead to an explosive eruption. Rapid detection of an ash-producing eruption would be accomplished using a combination of seismic, infrasound, lightning, and satellite data.
(12) Volcanic cloud height: n/a
(13) Other volcanic cloud information: n/a
(14) Remarks: Great Sitkin Volcano is a basaltic andesite volcano that occupies most of the northern half of Great Sitkin Island, a member of the Andreanof Islands group in the central Aleutian Islands. It is located 43 km (26 miles) east of the community of Adak. The volcano is a composite structure consisting of an older dissected volcano and a younger parasitic cone with a 3-km-diameter summit crater. A steep-sided lava dome, emplaced during an eruption in 1974, occupies the center of the crater. Great Sitkin erupted at least three times in the 20th century, most recently in 1974. That eruption produced at least one ash cloud that likely exceeded an altitude of 25,000 ft above sea level. A poorly documented eruption occurred in 1945, also producing a lava dome that was partially destroyed in the 1974 eruption. Within the past 280 years a large explosive eruption produced pyroclastic flows that partially filled the Glacier Creek valley on the southwest flank.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI
dfee1@alaska.edu (907) 322-4085
(16) Next Notice:
2020-02-15 - Semisopochnoi, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20200215/0919Z)
(3) Volcano: Semisopochnoi (VNUM #311060)
(4) Current Color Code: ORANGE
(5) Previous Color Code: YELLOW
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 51 deg 55 min E 179 deg 35 min
(9) Area: Aleutians
(10) Summit Elevation: 2625 ft (800 m)
(11) Volcanic Activity Summary: A series of small explosions and tremor bursts have been detected in seismic data at Semisopochnoi over the past 7 hours and are continuing, representing a significant uptick in activity. No ash plumes have been observed, however low-level ash emissions may accompany these minor explosions. Any ash emissions may be currently obscured by cloud cover at ~10,000 ft. The Alaska Volcano Observatory is therefore raising the Aviation Color Code to ORANGE and the Alert Level to WATCH.
(12) Volcanic cloud height: No cloud observed
(13) Other volcanic cloud information: No cloud observed
(14) Remarks: Semisopochnoi is monitored with an on-island seismic network, and remotely by satellite and lightning sensors. An infrasound array on Adak Island could detect explosive emissions from Semisopochnoi with a 13 minute delay if atmospheric conditions permit.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Taryn Lopez, Acting Coordinating Scientist, UAFGI
tmlopez@alaska.edu (907) 322-4085
(16) Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at
http://www.avo.alaska.edu
2020-02-07 - Shishaldin, Aviation Color Code: YELLOW (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20200207/0120Z)
(3) Volcano: Shishaldin (VNUM #311360)
(4) Current Color Code: YELLOW
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 54 deg 45 min W 163 deg 58 min
(9) Area: Aleutians
(10) Summit Elevation: 9373 ft (2857 m)
(11) Volcanic Activity Summary: Seismicity at Shishaldin Volcano has decreased over the past week to levels slightly above background. In addition, satellite views of the volcano over the same period show a decrease in surface temperatures at the summit. Eruptive activity appears to have ended or paused. Due to this decrease in activity, the Alaska Volcano Observatory is decreasing the Aviation Color Code for Shishaldin Volcano to YELLOW and the Alert Level to ADVISORY.

It is possible for eruptive activity to resume with little warning and AVO will continue to monitor the volcano closely.

Shishaldin is monitored by local seismic and infrasound sensors, satellite data, a web camera, a telemetered geodetic network, and distant infrasound and lightning networks.
(12) Volcanic cloud height: na
(13) Other volcanic cloud information: na
(14) Remarks: Shishaldin volcano, located near the center of Unimak Island in the eastern Aleutian Islands, is a spectacular symmetric cone with a base diameter of approximately 16 km (10 mi). A 200-m-wide (660 ft) funnel-shaped summit crater typically emits a steam plume and occasional small amounts of ash. Shishaldin is one of the most active volcanoes in the Aleutian volcanic arc, with at least 54 episodes of unrest including over 24 confirmed eruptions since 1775. Most eruptions are relatively small, although the April-May 1999 event generated an ash column that reached 45,000 ft above sea level.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Pavel Izbekov, Acting Coordinating Scientist, UAFGI
peizbekov@alaska.edu (907) 322-4085
(16) Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at http://www.avo.alaska.edu
2020-01-20 - Shishaldin, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20200120/0937Z)
(3) Volcano: Shishaldin (VNUM #311360)
(4) Current Color Code: ORANGE
(5) Previous Color Code: RED
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2020/A63
(8) Volcano Location: N 54 deg 45 min W 163 deg 58 min
(9) Area: Aleutians
(10) Summit Elevation: 9373 ft (2857 m)
(11) Volcanic Activity Summary: Ash emissions declined greatly at about 8:30 PM AKST (5:30 UTC 20 January). Seismicity is currently low. The Aviation Color Code is lowered to ORANGE and Alert Level to WATCH.

Satellite images show the detached volcanic cloud drifting east-southeast over the Pacific Ocean. A sigmet from the National Weather Service is still in effect for the detached cloud: https://www.weather.gov/aawu/sigmets

Low-level steam and ash emissions may be ongoing from the summit vent. It is possible for more significant eruption to resume with little warning.

Shishaldin is monitored by local seismic and infrasound sensors, satellite data, a web camera, a telemetered geodetic network, and distant infrasound and lightning networks.
(12) Volcanic cloud height: na
(13) Other volcanic cloud information: na
(14) Remarks: Shishaldin volcano, located near the center of Unimak Island in the eastern Aleutian Islands, is a spectacular symmetric cone with a base diameter of approximately 16 km (10 mi). A 200-m-wide (660 ft) funnel-shaped summit crater typically emits a steam plume and occasional small amounts of ash. Shishaldin is one of the most active volcanoes in the Aleutian volcanic arc, with at least 54 episodes of unrest including over 24 confirmed eruptions since 1775. Most eruptions are relatively small, although the April-May 1999 event generated an ash column that reached 45,000 ft above sea level.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI
dfee1@alaska.edu (907) 322-4085
(16) Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at http://www.avo.alaska.edu
2020-01-19 - Shishaldin, Aviation Color Code: RED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20200119/1728Z)
(3) Volcano: Shishaldin (VNUM #311360)
(4) Current Color Code: RED
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2020/A58
(8) Volcano Location: N 54 deg 45 min W 163 deg 58 min
(9) Area: Aleutians
(10) Summit Elevation: 9373 ft (2857 m)
(11) Volcanic Activity Summary: Starting at about 09:30 UTC (12:30 AM AKST), the eruption at Shishaldin intensified, and about two hours ago began generating a more ash-rich volcanic plume. The plume now extends from the summit 150 km east and is as high as about 20,000 ft asl, as seen in satellite data. Seismicity is elevated and the eruption is detected on regional infrasound arrays. The aviation color code is being raised to RED and the volcano alert level to WARNING.

The National Weather Service has issued a SIGMET for this activity.

(12) Volcanic cloud height: 20,000 ft asl
(13) Other volcanic cloud information: heading east
(14) Remarks: Shishaldin volcano, located near the center of Unimak Island in the eastern Aleutian Islands, is a spectacular symmetric cone with a base diameter of approximately 16 km (10 mi). A 200-m-wide (660 ft) funnel-shaped summit crater typically emits a steam plume and occasional small amounts of ash. Shishaldin is one of the most active volcanoes in the Aleutian volcanic arc, with at least 54 episodes of unrest including over 24 confirmed eruptions since 1775. Most eruptions are relatively small, although the April-May 1999 event generated an ash column that reached 45,000 ft above sea level.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI
dfee1@alaska.edu (907) 322-4085
(16) Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at http://www.avo.alaska.edu
2020-01-09 - Semisopochnoi, Aviation Color Code: YELLOW (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20200109/2325Z)
(3) Volcano: Semisopochnoi (VNUM #311060)
(4) Current Color Code: YELLOW
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2020/A17
(8) Volcano Location: N 51 deg 55 min E 179 deg 35 min
(9) Area: Aleutians
(10) Summit Elevation: 2625 ft (800 m)
(11) Volcanic Activity Summary: There has been no explosive activity observed at Semisopochnoi since December 19, 2019. Seismic tremor had decreased over the subsequent weeks with the last observation of seismic tremor on December 29, 2019. Seismicity has continued to decline, but remains above background. Thus, the Aviation Color Code is lowered to YELLOW and the Alert Level to ADVISORY.
(12) Volcanic cloud height: No cloud observed
(13) Other volcanic cloud information: No cloud observed
(14) Remarks: Semisopochnoi is monitored with an on-island seismic network, and remotely by satellite and lightning sensors. An infrasound array on Adak Island could detect explosive emissions from Semisopochnoi with a 13 minute delay if atmospheric conditions permit.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI
dfee1@alaska.edu (907) 322-4085
(16) Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at
http://www.avo.alaska.edu
2020-01-08 - Shishaldin, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20200108/0417Z)
(3) Volcano: Shishaldin (VNUM #311360)
(4) Current Color Code: ORANGE
(5) Previous Color Code: RED
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2020/A12
(8) Volcano Location: N 54 deg 45 min W 163 deg 58 min
(9) Area: Aleutians
(10) Summit Elevation: 9373 ft (2857 m)
(11) Volcanic Activity Summary: Ash emissions have declined significantly since about 12:00 PM AKST (21:00 UTC). The Aviation Color Code is lowered to ORANGE and Alert Level to WATCH.

Seismicity is currently low. Satellite data from this afternoon suggest continued low-level eruptive activity. It is possible for more explosive activity to resume with little warning.

Shishaldin is monitored by local seismic and infrasound sensors, satellite data, a web camera, a telemetered geodetic network, and distant infrasound and lightning networks.
(12) Volcanic cloud height: na
(13) Other volcanic cloud information: na
(14) Remarks: Shishaldin volcano, located near the center of Unimak Island in the eastern Aleutian Islands, is a spectacular symmetric cone with a base diameter of approximately 16 km (10 mi). A 200-m-wide (660 ft) funnel-shaped summit crater typically emits a steam plume and occasional small amounts of ash. Shishaldin is one of the most active volcanoes in the Aleutian volcanic arc, with at least 54 episodes of unrest including over 24 confirmed eruptions since 1775. Most eruptions are relatively small, although the April-May 1999 event generated an ash column that reached 45,000 ft above sea level.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI
dfee1@alaska.edu (907) 322-4085
(16) Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at http://www.avo.alaska.edu
2020-01-07 - Shishaldin, Aviation Color Code: RED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20200107/2133Z)
(3) Volcano: Shishaldin (VNUM #311360)
(4) Current Color Code: RED
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2020/A7
(8) Volcano Location: N 54 deg 45 min W 163 deg 58 min
(9) Area: Aleutians
(10) Summit Elevation: 9373 ft (2857 m)
(11) Volcanic Activity Summary: Ash eruption at Shishaldin continues and has intensified as shown in satellite and lightning data. Satellite data suggest the ash cloud is as high as 27,000 ft asl and drifting east-northeast. Aviation Color Code is RED and Alert Level is WARNING.

The National Weather Service has issued a SIGMET for this activity (https://www.weather.gov/aawu/).

It is possible for the current activity to intensify or decrease with little warning. AVO will issue further information as warranted.

Shishaldin is monitored by local seismic and infrasound sensors, satellite data, a web camera, a telemetered geodetic network, and distant infrasound and lightning networks.
(12) Volcanic cloud height: Up to 27,000 ft asl
(13) Other volcanic cloud information: Drifting ENE
(14) Remarks: Shishaldin volcano, located near the center of Unimak Island in the eastern Aleutian Islands, is a spectacular symmetric cone with a base diameter of approximately 16 km (10 mi). A 200-m-wide (660 ft) funnel-shaped summit crater typically emits a steam plume and occasional small amounts of ash. Shishaldin is one of the most active volcanoes in the Aleutian volcanic arc, with at least 54 episodes of unrest including over 24 confirmed eruptions since 1775. Most eruptions are relatively small, although the April-May 1999 event generated an ash column that reached 45,000 ft above sea level.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI
dfee1@alaska.edu (907) 322-4085
(16) Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at http://www.avo.alaska.edu
2020-01-07 - Shishaldin, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20200107/1839Z)
(3) Volcano: Shishaldin (VNUM #311360)
(4) Current Color Code: ORANGE
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2020/A6
(8) Volcano Location: N 54 deg 45 min W 163 deg 58 min
(9) Area: Aleutians
(10) Summit Elevation: 9373 ft (2857 m)
(11) Volcanic Activity Summary: Elevated seismicity since a little after 5:00 AM AKST today is continuing and likely accompanied by ash emissions. A volcanic cloud is visible in satellite data as high as about 23,000 ft asl drifting to the east-northeast of the volcano. Strongly elevated and saturated surface temperatures in satellite imagery are indicative of active lava effusion at the summit vent. Shishaldin remains at Aviation Color Code ORANGE and Alert Level WATCH.

The National Weather Service has issued a SIGMET to 23,000 ft above sea level (https://www.weather.gov/aawu/).

It is possible for the current activity to intensify or decrease with little warning. AVO will issue further information as warranted.

Shishaldin is monitored by local seismic and infrasound sensors, satellite data, a web camera, a telemetered geodetic network, and distant infrasound and lightning networks.
(12) Volcanic cloud height: Up to 23,000 ft asl
(13) Other volcanic cloud information: Drifting ENE
(14) Remarks: Shishaldin volcano, located near the center of Unimak Island in the eastern Aleutian Islands, is a spectacular symmetric cone with a base diameter of approximately 16 km (10 mi). A 200-m-wide (660 ft) funnel-shaped summit crater typically emits a steam plume and occasional small amounts of ash. Shishaldin is one of the most active volcanoes in the Aleutian volcanic arc, with at least 54 episodes of unrest including over 24 confirmed eruptions since 1775. Most eruptions are relatively small, although the April-May 1999 event generated an ash column that reached 45,000 ft above sea level.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI
dfee1@alaska.edu (907) 322-4085
(16) Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at http://www.avo.alaska.edu
2020-01-03 - Shishaldin, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20200103/2038Z)
(3) Volcano: Shishaldin (VNUM #311360)
(4) Current Color Code: ORANGE
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2020/A1
(8) Volcano Location: N 54 deg 45 min W 163 deg 58 min
(9) Area: Aleutians
(10) Summit Elevation: 9373 ft (2857 m)
(11) Volcanic Activity Summary: Eruptive activity occurring at Shishaldin Volcano. Activity this morning has produced an ash cloud to 20,000 - 24,000 feet that is moving to the E-SE. The level of seismic activity has increased to moderate levels and several pilot observations of ash clouds have been reported to AVO. The ash cloud is visible in satellite data and extends 15-20 miles beyond the volcano to the southeast. Shishaldin remains at Aviation Color Code ORANGE and Alert Level WATCH. The National Weather Service has issued SIGMET to 24,000 ft above sea level (https://www.weather.gov/aawu/).

Shishadin remains at a heightened level of unrest and explosions may occur with little warning.

Shishaldin is monitored by local seismic and infrasound sensors, satellite data, a web camera, a telemetered geodetic network, and distant infrasound and lightning networks.
(12) Volcanic cloud height: 24,000
(13) Other volcanic cloud information: Unknown
(14) Remarks: Shishaldin volcano, located near the center of Unimak Island in the eastern Aleutian Islands, is a spectacular symmetric cone with a base diameter of approximately 16 km (10 mi). A 200-m-wide (660 ft) funnel-shaped summit crater typically emits a steam plume and occasional small amounts of ash. Shishaldin is one of the most active volcanoes in the Aleutian volcanic arc, with at least 54 episodes of unrest including over 24 confirmed eruptions since 1775. Most eruptions are relatively small, although the April-May 1999 event generated an ash column that reached 45,000 ft above sea level.
(15) Contacts: Matt Haney, Acting Scientist-in-Charge, USGS
mhaney@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI
dfee1@alaska.edu (907) 322-4085
(16) Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at
http://www.avo.alaska.edu
2019-12-28 - Pavlof, Aviation Color Code: YELLOW (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20191228/2043Z)
(3) Volcano: Pavlof (VNUM #312030)
(4) Current Color Code: YELLOW
(5) Previous Color Code: GREEN
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 55 deg 25 min W 161 deg 53 min
(9) Area: Alaska Peninsula
(10) Summit Elevation: 8261 ft (2518 m)
(11) Volcanic Activity Summary: Over the past several days seismic activity has increased at Pavlof. No eruptive activity or emissions from the summit have been observed. However, the seismic activity represents an increase from background levels and we are thus increasing the the Aviation Color Code and Alert Level to YELLOW/ADVISORY. This does not mean that an eruption is likely or imminent. However, past eruptions of Pavlof occurred with little or no warning.
(12) Volcanic cloud height: None
(13) Other volcanic cloud information: None
(14) Remarks: Pavlof Volcano is a snow- and ice-covered stratovolcano located on the southwestern end of the Alaska Peninsula about 953 km (592 mi) southwest of Anchorage. The volcano is about 7 km (4.4 mi) in diameter and has active vents on the north and east sides close to the summit. With over 40 historic eruptions, it is one of the most consistently active volcanoes in the Aleutian arc. Eruptive activity is generally characterized by sporadic Strombolian lava fountaining continuing for a several-month period. Ash plumes as high as 49,000 ft ASL have been generated by past eruptions of Pavlof, and during the March 2016 eruption, ash plumes as high as 40,000 feet above sea level were generated and the ash was tracked in satellite data as distant as eastern Canada. The nearest community, Cold Bay, is located 60 km (37 miles) to the southwest of Pavlof.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI
dfee1@alaska.edu (907) 322-4085
(16) Next Notice:
2019-12-12 - Shishaldin, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20191212/1718Z)
(3) Volcano: Shishaldin (VNUM #311360)
(4) Current Color Code: ORANGE
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 54 deg 45 min W 163 deg 58 min
(9) Area: Aleutians
(10) Summit Elevation: 9373 ft (2857 m)
(11) Volcanic Activity Summary: A short-lived explosion from Shishaldin Volcano has produced an ash cloud to 20,000 - 25,000 feet and is moving to the W-NW. A tremor burst was observed in seismic data at 7:10 (16:10 UTC) and had a duration of about 3 minutes. Three lightning stroke were detected. Shishaldin remains at Aviation Color Code ORANGE and Alert Level WATCH. The National Weather Service has issued SIGMET to 25,000 ft above sea level (https://www.weather.gov/aawu/).

Shishadin remains at a heightened level of unrest and explosions may occur with little warning.

Shishaldin is monitored by local seismic and infrasound sensors, satellite data, a web camera, a telemetered geodetic network, and distant infrasound and lightning networks.
(12) Volcanic cloud height: 25,000
(13) Other volcanic cloud information: Rising above cloud deck moving to the W-NW from Shishaldin at approximately 45 knots
(14) Remarks: Shishaldin volcano, located near the center of Unimak Island in the eastern Aleutian Islands, is a spectacular symmetric cone with a base diameter of approximately 16 km (10 mi). A 200-m-wide (660 ft) funnel-shaped summit crater typically emits a steam plume and occasional small amounts of ash. Shishaldin is one of the most active volcanoes in the Aleutian volcanic arc, with at least 54 episodes of unrest including over 24 confirmed eruptions since 1775. Most eruptions are relatively small, although the April-May 1999 event generated an ash column that reached 45,000 ft above sea level.
(15) Contacts: Kristi Wallace, Acting Scientist-in-Charge, USGS
kwallace@usgs.gov (907) 786-7497

Janet Schaefer, Acting Coordinating Scientist, UAFGI
janet.schaefer@alaska.gov (907) 322-4085
(16) Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at
http://www.avo.alaska.edu
2019-12-07 - Semisopochnoi, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20191207/1025Z)
(3) Volcano: Semisopochnoi (VNUM #311060)
(4) Current Color Code: ORANGE
(5) Previous Color Code: YELLOW
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 51 deg 55 min E 179 deg 35 min
(9) Area: Aleutians
(10) Summit Elevation: 2625 ft (800 m)
(11) Volcanic Activity Summary: An eruption signature was detected as strong tremor on local seismic and in regional infrasound networks on Adak Island. The event started at 00:26 AKST / 09:26 UTC and has continued with and ongoing but weaker local seismic signal. Any volcanic ash emissions are most likely low-level.

The meteorological cloud deck has been around 10,000' (3000 m) asl over Semisopochnoi and no ash signals have been detected above this height. Nothing has been detected in lightning data.
(12) Volcanic cloud height: No cloud observed
(13) Other volcanic cloud information: No cloud observed
(14) Remarks: Semisopochnoi is monitored with an on-island seismic network, and remotely by satellite and lightning sensors. An infrasound array on Adak Island could detect explosive emissions from Semisopochnoi with a 13 minute delay if atmospheric conditions permit.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI
dfee1@alaska.edu (907) 322-4085
(16) Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at
http://www.avo.alaska.edu
2019-11-15 - Cleveland, Aviation Color Code: YELLOW (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20191115/2116Z)
(3) Volcano: Cleveland (VNUM #311240)
(4) Current Color Code: YELLOW
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 52 deg 49 min W 169 deg 56 min
(9) Area: Aleutians
(10) Summit Elevation: 5676 ft (1730 m)
(11) Volcanic Activity Summary: Satellite data over the past week and regional seismic and infrasound data show no evidence of eruptive activity. Thus, AVO is lowering the Aviation Color Code to YELLOW and the Volcano Alert Level to ADVISORY.

Future explosions at Cleveland are likely. They occur without warning and typically produce relatively small volcanic ash clouds that dissipate within hours; however, more significant ash emissions are possible.
(12) Volcanic cloud height: None
(13) Other volcanic cloud information: n/a
(14) Remarks: Cleveland volcano is monitored by only two seismic stations, which restricts AVO's ability to detect precursory unrest that may lead to an explosive eruption. Rapid detection of an ash-producing eruption may be possible using a combination of seismic, infrasound, lightning, and satellite data.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Pavel Izbekov, Acting Coordinating Scientist, UAFGI
peizbekov@alaska.edu (907) 322-4085
(16) Next Notice:
2019-11-08 - Cleveland, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20191108/2033Z)
(3) Volcano: Cleveland (VNUM #311240)
(4) Current Color Code: ORANGE
(5) Previous Color Code: YELLOW
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 52 deg 49 min W 169 deg 56 min
(9) Area: Aleutians
(10) Summit Elevation: 5676 ft (1730 m)
(11) Volcanic Activity Summary: Satellite data from the past day suggest that slow effusion of lava may have begun in the summit crater. Thus, AVO is increasing the Aviation Color Code to ORANGE and the Volcano Alert Level to WATCH. Highly elevated surface temperatures consistent with lava at the surface have been observed over the past day and robust steaming was seen in web camera and satellite data yesterday. No evidence of explosive, ash-producing activity observed.

Future explosions at Cleveland are likely and the presence of a lava dome in the summit crater may increase the possibility of this type of activity. They occur without warning and typically produce relatively small volcanic ash clouds that dissipate within hours; however, more significant ash emissions are possible.
(12) Volcanic cloud height: None
(13) Other volcanic cloud information: n/a
(14) Remarks: Cleveland volcano is monitored by only two seismic stations, which restricts AVO's ability to detect precursory unrest that may lead to an explosive eruption. Rapid detection of an ash-producing eruption may be possible using a combination of seismic, infrasound, lightning, and satellite data.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Pavel Izbekov, Acting Coordinating Scientist, UAFGI
peizbekov@alaska.edu (907) 322-4085
(16) Next Notice:
2019-11-06 - Pavlof, Aviation Color Code: GREEN (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20191106/1946Z)
(3) Volcano: Pavlof (VNUM #312030)
(4) Current Color Code: GREEN
(5) Previous Color Code: YELLOW
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 55 deg 25 min W 161 deg 53 min
(9) Area: Alaska Peninsula
(10) Summit Elevation: 8261 ft (2518 m)
(11) Volcanic Activity Summary: The Alaska Volcano Observatory is reducing the Aviation Color Code to GREEN and the Alert Level to NORMAL. Small explosion signals from Pavlof were detected on October 19, 2019 on the infrasound network located at Sand Point and on the on the local seismic and infrasound network. Since that time there have not been additional signs of unrest in any of the monitoring data. Pavlof is now considered to have returned to background levels of activity.
(12) Volcanic cloud height: None
(13) Other volcanic cloud information: None
(14) Remarks: Pavlof Volcano is a snow- and ice-covered stratovolcano located on the southwestern end of the Alaska Peninsula about 953 km (592 mi) southwest of Anchorage. The volcano is about 7 km (4.4 mi) in diameter and has active vents on the north and east sides close to the summit. With over 40 historic eruptions, it is one of the most consistently active volcanoes in the Aleutian arc. Eruptive activity is generally characterized by sporadic Strombolian lava fountaining continuing for a several-month period. Ash plumes as high as 49,000 ft ASL have been generated by past eruptions of Pavlof, and during the March 2016 eruption, ash plumes as high as 40,000 feet above sea level were generated and the ash was tracked in satellite data as distant as eastern Canada. The nearest community, Cold Bay, is located 60 km (37 miles) to the southwest of Pavlof.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI
dfee1@alaska.edu (907) 322-4085
(16) Next Notice:
2019-10-19 - Pavlof, Aviation Color Code: YELLOW (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20191019/2207Z)
(3) Volcano: Pavlof (VNUM #312030)
(4) Current Color Code: YELLOW
(5) Previous Color Code: GREEN
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 55 deg 25 min W 161 deg 53 min
(9) Area: Alaska Peninsula
(10) Summit Elevation: 8261 ft (2518 m)
(11) Volcanic Activity Summary: Small explosion signals from Pavlof have been detected on the infrasound network located at Sand Point and on the local seismic network today. The volcano is currently obscured by clouds in satellite images. It is unknown if the explosions produced any volcanic ash, but their small size suggests any hazard is currently confined to the area around the volcano's summit. Because these signals are above normal background for Pavlof, the Alaska Volcano Observatory is raising the Aviation Color Code to YELLOW and the Alert Level to ADVISORY.
(12) Volcanic cloud height: None
(13) Other volcanic cloud information: None
(14) Remarks: Pavlof Volcano is a snow- and ice-covered stratovolcano located on the southwestern end of the Alaska Peninsula about 953 km (592 mi) southwest of Anchorage. The volcano is about 7 km (4.4 mi) in diameter and has active vents on the north and east sides close to the summit. With over 40 historic eruptions, it is one of the most consistently active volcanoes in the Aleutian arc. Eruptive activity is generally characterized by sporadic Strombolian lava fountaining continuing for a several-month period. Ash plumes as high as 49,000 ft ASL have been generated by past eruptions of Pavlof, and during the March 2016 eruption, ash plumes as high as 40,000 feet above sea level were generated and the ash was tracked in satellite data as distant as eastern Canada. The nearest community, Cold Bay, is located 60 km (37 miles) to the southwest of Pavlof.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI
dfee1@alaska.edu (907) 322-4085

(16) Next Notice:
2019-10-17 - Shishaldin, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20191017/1906Z)
(3) Volcano: Shishaldin (VNUM #311360)
(4) Current Color Code: ORANGE
(5) Previous Color Code: YELLOW
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 54 deg 45 min W 163 deg 58 min
(9) Area: Aleutians
(10) Summit Elevation: 9373 ft (2857 m)
(11) Volcanic Activity Summary: Observations from today show that a new lava effusion event began at Shishaldin on 13 October. Elevated surface temperatures have been observed at the summit of Shishaldin and low-level seismicity continues on the local network indicating that eruptive activity is likely continuing. The eruption is confined to the summit area and no ash clouds have been observed. The Alaska Volcano Observatory is raising the Aviation Color Code for Shishaldin Volcano to ORANGE and the Alert Level to WATCH.

Shishaldin is monitored by local seismic and infrasound sensors, satellite data, a web camera, a telemetered geodetic network, and distant infrasound and lightning networks.
(12) Volcanic cloud height: None
(13) Other volcanic cloud information: N/A
(14) Remarks: Shishaldin volcano, located near the center of Unimak Island in the eastern Aleutian Islands, is a spectacular symmetric cone with a base diameter of approximately 16 km (10 mi). A 200-m-wide (660 ft) funnel-shaped summit crater typically emits a steam plume and occasional small amounts of ash. Shishaldin is one of the most active volcanoes in the Aleutian volcanic arc, with at least 54 episodes of unrest including over 24 confirmed eruptions since 1775. Most eruptions are relatively small, although the April-May 1999 event generated an ash column that reached 45,000 ft above sea level.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Taryn Lopez, Acting Coordinating Scientist, UAFGI
tmlopez@alaska.edu (907) 322-4085

(16) Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at
http://www.avo.alaska.edu
2019-09-26 - Shishaldin, Aviation Color Code: YELLOW (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20190926/2109Z)
(3) Volcano: Shishaldin (VNUM #311360)
(4) Current Color Code: YELLOW
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 54 deg 45 min W 163 deg 58 min
(9) Area: Aleutians
(10) Summit Elevation: 9373 ft (2857 m)
(11) Volcanic Activity Summary: Seismicity at Shishaldin Volcano has decreased over the past few weeks to levels slightly above background. In addition, satellite views of the volcano over the same period show a decrease in surface temperatures at the summit. Eruptive activity appears to have ended or paused. Due to this decrease in activity, the Alaska Volcano Observatory is decreasing the Aviation Color Code for Shishaldin Volcano to YELLOW and the Alert Level to ADVISORY.

Shishaldin is monitored by local seismic and infrasound sensors, satellite data, a web camera, a telemetered geodetic network, and distant infrasound and lightning networks.
(12) Volcanic cloud height: None
(13) Other volcanic cloud information: N/A
(14) Remarks: Shishaldin volcano, located near the center of Unimak Island in the eastern Aleutian Islands, is a spectacular symmetric cone with a base diameter of approximately 16 km (10 mi). A 200-m-wide (660 ft) funnel-shaped summit crater typically emits a steam plume and occasional small amounts of ash. Shishaldin is one of the most active volcanoes in the Aleutian volcanic arc, with at least 54 episodes of unrest including over 24 confirmed eruptions since 1775. Most eruptions are relatively small, although the April-May 1999 event generated an ash column that reached 45,000 ft above sea level.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI
dfee1@alaska.edu (907) 322-4085

(16) Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at
http://www.avo.alaska.edu
2019-09-18 - Semisopochnoi, Aviation Color Code: YELLOW (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20190918/2110Z)
(3) Volcano: Semisopochnoi (VNUM #311060)
(4) Current Color Code: YELLOW
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 51 deg 55 min E 179 deg 35 min
(9) Area: Aleutians
(10) Summit Elevation: 2625 ft (800 m)
(11) Volcanic Activity Summary: Seismicity at Semisopochnoi has decreased over the past few weeks with no observations of seismic tremor since September 15. Low-level sulfur dioxide emissions continue to be observed when conditions permit. Other than the ongoing refilling of the crater lake, no changes in surface features have been observed since the small, shallow cone that formed around August 24. Due to the decrease in activity, AVO is lowering the color code/activity level to YELLOW/ADVISORY.
(12) Volcanic cloud height: No cloud observed
(13) Other volcanic cloud information: No cloud observed
(14) Remarks: Semisopochnoi is monitored with an on-island seismic network, and remotely by satellite and lightning sensors. An infrasound array on Adak Island could detect explosive emissions from Semisopochnoi with a 13 minute delay if atmospheric conditions permit.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI
dfee1@alaska.edu (907) 322-4085
(16) Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at
http://www.avo.alaska.edu
2019-09-06 - Wrangell, Aviation Color Code: GREEN (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20190906/1828Z)
(3) Volcano: Wrangell (VNUM #315020)
(4) Current Color Code: GREEN
(5) Previous Color Code: UNASSIGNED
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 62 deg W 144 deg 1 min
(9) Area: Wrangell Volcanic Field
(10) Summit Elevation: 14163 ft (4317 m)
(11) Volcanic Activity Summary: The Alaska Volcano Observatory (AVO) has reestablished seismic monitoring instruments at Mount Wrangell and can now confidently monitor seismic unrest at the volcano. With renewed seismic monitoring, the volcano moves from "UNASSIGNED" to Volcano Alert Level NORMAL and Aviation Color Code GREEN. As at other Alaska volcanoes, AVO will continue to use satellite, infrasound, and lightning data, and reports from pilots and ground observers to detect signs of eruptive activity.
(12) Volcanic cloud height: Not applicable
(13) Other volcanic cloud information: Not applicable
(14) Remarks: Mt. Wrangell is a 4317 m (14,163 ft) high, andesitic, shield volcano with an ice-filled summit caldera, located in the Wrangell-St. Elias National Park and Preserve. Mt. Wrangell has three small post-caldera craters, named North Crater, East Crater, and Mt. Zanetti. These craters are all geothermally active, and there are frequent historical reports of steam from Mt. Wrangell. There are also several questionable reports of historical eruptive activity. Mt. Wrangell is 330 km (206 mi) northeast of Anchorage.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS, mcoombs@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI, dfee1@alaska.edu (907) 322-4085
(16) Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at
http://www.avo.alaska.edu
2019-09-06 - Dutton, Aviation Color Code: GREEN (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20190906/1827Z)
(3) Volcano: Dutton (VNUM #312011)
(4) Current Color Code: GREEN
(5) Previous Color Code: UNASSIGNED
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 55 deg 11 min W 162 deg 16 min
(9) Area: Alaska Peninsula
(10) Summit Elevation: 4833 ft (1473 m)
(11) Volcanic Activity Summary: The Alaska Volcano Observatory (AVO) has reestablished seismic monitoring instruments at Mount Dutton and can now confidently monitor seismic unrest at the volcano. With renewed seismic monitoring, the volcano moves from "UNASSIGNED" to Volcano Alert Level NORMAL and Aviation Color Code GREEN. As at other Alaska volcanoes, AVO will continue to use satellite, infrasound, and lightning data, and reports from pilots and ground observers to detect signs of eruptive activity.
(12) Volcanic cloud height: Not applicable
(13) Other volcanic cloud information: Not applicable
(14) Remarks: Mount Dutton is located near the tip of the Alaska Peninsula and lies jointly within the Izembek Wilderness Area and the Alaska Peninsula Wildlife Refuge. Dutton is a snow- and ice-covered stratovlocano which rises to an elevation of 4833 feet. Although it has no historic eruptive activity, intense earthquake swarms occurred at the volcano in 1984 and 1988. Dutton is located 14 km (9 miles) north of King Cove and 30 km (19 miles) east of Cold Bay.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS, mcoombs@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGIdfee1@alaska.edu (907) 322-4085
(16) Next Notice:
2019-08-25 - Veniaminof, Aviation Color Code: GREEN (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20190825/2051Z)
(3) Volcano: Veniaminof (VNUM #312070)
(4) Current Color Code: GREEN
(5) Previous Color Code: YELLOW
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 56 deg 11 min W 159 deg 23 min
(9) Area: Alaska Peninsula
(10) Summit Elevation: 8225 ft (2507 m)
(11) Volcanic Activity Summary: Following pilot reports of steaming and the detection of low-level tremor at Veniaminof on August 1, the volcano has returned to background activity. Therefore AVO is lowering the Aviation Color Code to GREEN and the Volcano Alert Level to NORMAL.
(12) Volcanic cloud height: None
(13) Other volcanic cloud information: n/a
(14) Remarks:
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI
dfee1@alaska.edu (907) 322-4085
(16) Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at
http://www.avo.alaska.edu
2019-08-01 - Veniaminof, Aviation Color Code: YELLOW (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20190801/2221Z)
(3) Volcano: Veniaminof (VNUM #312070)
(4) Current Color Code: YELLOW
(5) Previous Color Code: GREEN
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 56 deg 11 min W 159 deg 23 min
(9) Area: Alaska Peninsula
(10) Summit Elevation: 8225 ft (2507 m)
(11) Volcanic Activity Summary: Pilot reports of steaming coincided with low-level tremor recorded at Veniaminof at 20:30 UTC (12:30 AKDT). These observations mark a departure from recent background activity. Therefore AVO is raising the Aviation Color Code to YELLOW and the Volcano Alert Level to ADVISORY.
(12) Volcanic cloud height: None
(13) Other volcanic cloud information: n/a
(14) Remarks:
(15) Contacts: Matt Haney, Acting Scientist-in-Charge, USGS
mhaney@usgs.gov (907) 786-7497

Cheryl Cameron, Acting Coordinating Scientist, ADGGS
cheryl.cameron@alaska.gov (907) 322-4085
(16) Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at
http://www.avo.alaska.edu
2019-07-24 - Shishaldin, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20190724/1939Z)
(3) Volcano: Shishaldin (VNUM #311360)
(4) Current Color Code: ORANGE
(5) Previous Color Code: YELLOW
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 54 deg 45 min W 163 deg 58 min
(9) Area: Aleutians
(10) Summit Elevation: 9373 ft (2857 m)
(11) Volcanic Activity Summary: The Alaska Volcano Observatory is raising the Aviation Color Code to ORANGE and the Alert Level to WATCH at Shishaldin Volcano. Field crews reported an active lava lake and minor spattering within the summit crater during a helicopter overflight. Elevated seismic activity continues similar to the past few weeks along with consistent elevated surface temperatures in satellite images. No lava or ash has erupted outside the summit crater at this time.

Shishaldin is monitored by local seismic and infrasound sensors, satellite data, a web camera, a telemetered geodetic network, and distant infrasound and lightning networks.
(12) Volcanic cloud height: None
(13) Other volcanic cloud information: N/A
(14) Remarks: Shishaldin volcano, located near the center of Unimak Island in the eastern Aleutian Islands, is a spectacular symmetric cone with a base diameter of approximately 16 km (10 mi). A 200-m-wide (660 ft) funnel-shaped summit crater typically emits a steam plume and occasional small amounts of ash. Shishaldin is one of the most active volcanoes in the Aleutian volcanic arc, with at least 54 episodes of unrest including over 24 confirmed eruptions since 1775. Most eruptions are relatively small, although the April-May 1999 event generated an ash column that reached 45,000 ft above sea level.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jessica Larsen, Acting Coordinating Scientist, UAFGI
jflarsen@alaska.edu (907) 322-4085

(16) Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at
http://www.avo.alaska.edu
2019-07-18 - Semisopochnoi, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20190718/1838Z)
(3) Volcano: Semisopochnoi (VNUM #311060)
(4) Current Color Code: ORANGE
(5) Previous Color Code: YELLOW
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 51 deg 55 min E 179 deg 35 min
(9) Area: Aleutians
(10) Summit Elevation: 2625 ft (800 m)
(11) Volcanic Activity Summary: Elevated seismicity that began yesterday has increased overnight. A stronger tremor signal recorded at 23:39 AKDT / 07:39 UTC also produced an infrasound signal on an infrasound array 260 km (161 miles) east on Adak island. This event likely produced ash emissions, and at the current level of continued unrest similar events could occur with little to no warning. The meteorological cloud deck has been around 10,000' (3000 m) asl over Semisopochnoi and no ash signals have been detected above this height. A small plume extending 18 km (11 miles) from the Cerberus vent was visible in satellite data from yesterday, but did not contain an ash signal.

Nothing has been detected in lightning data.
(12) Volcanic cloud height: No cloud observed
(13) Other volcanic cloud information: No cloud observed
(14) Remarks: Semisopochnoi is monitored with an on-island seismic network, and remotely by satellite and lightning sensors. An infrasound array on Adak Island could detect explosive emissions from Semisopochnoi with a 13 minute delay if atmospheric conditions permit.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jessica Larsen, Acting Coordinating Scientist, UAFGI
jflarsen@alaska.edu (907) 322-4085

(16) Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at
http://www.avo.alaska.edu
2019-07-15 - Great Sitkin, Aviation Color Code: GREEN (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20190715/1939Z)
(3) Volcano: Great Sitkin (VNUM #311120)
(4) Current Color Code: GREEN
(5) Previous Color Code: YELLOW
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 52 deg 4 min W 176 deg 6 min
(9) Area: Aleutians
(10) Summit Elevation: 5709 ft (1740 m)
(11) Volcanic Activity Summary: Seismic activity at Great Sitkin Volcano has decreased to background levels over the past few weeks. There is no evidence of eruptive activity in geophysical data streams or in satellite observations. Thus, AVO is decreasing the Aviation Color Code to GREEN and Alert Level to NORMAL.

Great Sitkin is monitored with a local real-time seismic network, which will typically allow AVO to detect changes in unrest that may lead to an explosive eruption. Rapid detection of an ash-producing eruption would be accomplished using a combination of seismic, infrasound, lightning, and satellite data.
(12) Volcanic cloud height: n/a
(13) Other volcanic cloud information: n/a
(14) Remarks: Great Sitkin Volcano is a basaltic andesite volcano that occupies most of the northern half of Great Sitkin Island, a member of the Andreanof Islands group in the central Aleutian Islands. It is located 43 km (26 miles) east of the community of Adak. The volcano is a composite structure consisting of an older dissected volcano and a younger parasitic cone with a 3-km-diameter summit crater. A steep-sided lava dome, emplaced during an eruption in 1974, occupies the center of the crater. Great Sitkin erupted at least three times in the 20th century, most recently in 1974. That eruption produced at least one ash cloud that likely exceeded an altitude of 25,000 ft above sea level. A poorly documented eruption occurred in 1945, also producing a lava dome that was partially destroyed in the 1974 eruption. Within the past 280 years a large explosive eruption produced pyroclastic flows that partially filled the Glacier Creek valley on the southwest flank.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI
dfee1@alaska.edu (907) 322-4085

(16) Next Notice:
2019-07-12 - Shishaldin, Aviation Color Code: YELLOW (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20190712/2109Z)
(3) Volcano: Shishaldin (VNUM #311360)
(4) Current Color Code: YELLOW
(5) Previous Color Code: GREEN
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 54 deg 45 min W 163 deg 58 min
(9) Area: Aleutians
(10) Summit Elevation: 9373 ft (2857 m)
(11) Volcanic Activity Summary: The Alaska Volcano Observatory is raising the Aviation Color Code to YELLOW and the Alert Level to ADVISORY at Shishaldin Volcano. This change is based on increased seismic activity over the past few weeks, accompanied by elevated surface temperatures at the summit in satellite data. A pilot also observed incandescence in the summit crater during a recent overflight. These observations represent a departure from normal background activity at Shishaldin, but do not necessarily indicate that an eruption will occur.

Shishaldin is monitored by local seismic and infrasound sensors, satellite data, a web camera, a telemetered geodetic network, and distant infrasound and lightning networks.
(12) Volcanic cloud height: None
(13) Other volcanic cloud information: N/A
(14) Remarks: Shishaldin volcano, located near the center of Unimak Island in the eastern Aleutian Islands, is a spectacular symmetric cone with a base diameter of approximately 16 km (10 mi). A 200-m-wide (660 ft) funnel-shaped summit crater typically emits a steam plume and occasional small amounts of ash. Shishaldin is one of the most active volcanoes in the Aleutian volcanic arc, with at least 54 episodes of unrest including over 24 confirmed eruptions since 1775. Most eruptions are relatively small, although the April-May 1999 event generated an ash column that reached 45,000 ft above sea level.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI
dfee1@alaska.edu (907) 322-4085

(16) Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at
http://www.avo.alaska.edu
2019-07-05 - Semisopochnoi, Aviation Color Code: YELLOW (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20190705/0651Z)
(3) Volcano: Semisopochnoi (VNUM #311060)
(4) Current Color Code: YELLOW
(5) Previous Color Code: UNASSIGNED
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 51 deg 55 min E 179 deg 35 min
(9) Area: Aleutians
(10) Summit Elevation: 2625 ft (800 m)
(11) Volcanic Activity Summary: Due to an increase in seismicity above background levels over at least the last 8 hours AVO is raising the Aviation Color Code to YELLOW and Alert Level to ADVISORY at Semisopochnoi. No explosive activity has been detected on the Adak infrasound array and clouds currently obscure satellite views of the volcano.

AVO will continue to monitor the volcano using satellite, infrasound and seismic data.
(12) Volcanic cloud height: No cloud observed
(13) Other volcanic cloud information: No cloud observed
(14) Remarks:
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Pavel Izbekov, Acting Coordinating Scientist, UAFGI
peizbekov@alaska.edu (907) 322-4085
(16) Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at
http://www.avo.alaska.edu
2019-07-02 - Mauna Loa, Aviation Color Code: YELLOW (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20190702/1740Z)
(3) Volcano: Mauna Loa (VNUM #332020)
(4) Current Color Code: YELLOW
(5) Previous Color Code: GREEN
(6) Source: Hawaiian Volcano Observatory
(7) Notice Number: 2019/H28
(8) Volcano Location: N 19 deg 28 min W 155 deg 36 min
(9) Area: Hawaii
(10) Summit Elevation: 13681 ft (4170 m)
(11) Volcanic Activity Summary: For the past several months, earthquake and ground deformation rates at Mauna Loa Volcano have exceeded long term background levels. An eruption is not imminent and current rates are not cause for alarm. However, they do indicate changes in the shallow magma storage system at Mauna Loa.

Following a significant earthquake swarm in October 2018, HVO seismic stations have recorded an average of at least 50 shallow, small-magnitude earthquakes per week beneath Mauna Loa's summit, upper Southwest Rift Zone, and upper west flank. This compares to a rate of fewer than 20 per week in the first half of 2018. Shallow earthquakes are occurring in locations similar to those that preceded Mauna Loa's most recent eruptions in 1975 and 1984.

During this same time period, GPS instrumentation and satellite radar have measured ground deformation consistent with renewed recharge of the volcano's shallow magma storage system. The current rate and pattern of ground deformation is similar to that measured during inflation of Mauna Loa in 2005 and again from 2014 - 2018.

Together, these observations indicate the volcano is no longer at a background level of activity. Accordingly, HVO is elevating the Mauna Loa alert level to ADVISORY and the aviation color code to YELLOW.

Alert levels and aviation color codes are explained here: https://volcanoes.usgs.gov/vhp/about_alerts.html

This increase in alert level does not mean that an eruption is imminent nor that progression to an eruption is certain. A similar increase in activity occurred between 2014 and 2018 and no eruption occurred.
(12) Volcanic cloud height: N/A
(13) Other volcanic cloud information: N/A
(14) Remarks: Prognosis

As has happened before, it is possible that current low-level unrest will continue and vary in intensity for many months, or even years without an eruption. It is also possible that the current unrest is an early precursor to an eventual eruption. At this time, we cannot determine which of these possibilities is more likely.

HVO expects that days or weeks prior to an eruption, monitoring instruments will detect signs of an increased potential for eruption. These signs could include further increases in rates of earthquakes and ground deformation, increases in the sizes of earthquakes, an increase in surface temperatures, or an increase in visible steam plumes or sulfur dioxide emissions.

However, it is also possible that the timeframe to eruption could be shorter - hours to days. All communities on the flanks of the volcano should be prepared.

HVO continues to monitor the volcano closely and will report any significant changes. HVO is in close touch with Hawaii County Civil Defense and other agencies responsible for public safety.

Stay informed about Mauna Loa by following volcano updates and tracking current monitoring data on the HVO web page (http://hvo.wr.usgs.gov/activity/maunaloastatus.php) or by signing up to receive updates by email at this site: http://volcanoes.usgs.gov/vns/

Hawaii County Civil Defense Agency is in constant communications with HVO. If anything develops that may affect your safety, you will be informed.

Please sign up for Civil Defense notifications by visiting Hawaii County Civil Defense Agency webpage at http://www.hawaiicounty.gov/civil-defense/.
(15) Contacts: askHVO@usgs.gov
(16) Next Notice: Mauna Loa updates will be issued weekly. Should volcanic activity change significantly a new VAN will be issued. Regularly scheduled updates are posted at http://hvo.wr.usgs.gov
2019-06-12 - Pavlof, Aviation Color Code: GREEN (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20190612/1908Z)
(3) Volcano: Pavlof (VNUM #312030)
(4) Current Color Code: GREEN
(5) Previous Color Code: YELLOW
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 55 deg 25 min W 161 deg 53 min
(9) Area: Alaska Peninsula
(10) Summit Elevation: 8261 ft (2518 m)
(11) Volcanic Activity Summary: The elevated levels of seismic activity, apparent since about mid-May, have declined to background levels. Therefore we are lowering the Aviation Color Code and Alert Level to GREEN/NORMAL.

The volcano continues to emit a vapor plume that is occasionally visible in web camera views, and elevated surface temperatures continue to be observed occasionally at the summit crater in high-resolution satellite data. Such observations are common and reflect the steady emission of hot volcanic vapors from a near-vertically oriented vent.

(12) Volcanic cloud height: None
(13) Other volcanic cloud information: None
(14) Remarks: Pavlof Volcano is a snow- and ice-covered stratovolcano located on the southwestern end of the Alaska Peninsula about 953 km (592 mi) southwest of Anchorage. The volcano is about 7 km (4.4 mi) in diameter and has active vents on the north and east sides close to the summit. With over 40 historic eruptions, it is one of the most consistently active volcanoes in the Aleutian arc. Eruptive activity is generally characterized by sporadic Strombolian lava fountaining continuing for a several-month period. Ash plumes as high as 49,000 ft ASL have been generated by past eruptions of Pavlof, and during the March 2016 eruption, ash plumes as high as 40,000 feet above sea level were generated and the ash was tracked in satellite data as distant as eastern Canada. The nearest community, Cold Bay, is located 60 km (37 miles) to the southwest of Pavlof.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI
dfee1@alaska.edu (907) 322-4085
(16) Next Notice:
2019-06-02 - Great Sitkin, Aviation Color Code: YELLOW (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20190602/1903Z)
(3) Volcano: Great Sitkin (VNUM #311120)
(4) Current Color Code: YELLOW
(5) Previous Color Code: GREEN
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 52 deg 4 min W 176 deg 6 min
(9) Area: Aleutians
(10) Summit Elevation: 5709 ft (1740 m)
(11) Volcanic Activity Summary: A small steam explosion at 21:40 AKDT June 1 (5:40 UTC June 2) was detected at Great Sitkin Volcano in local seismic data. No corresponding signal was seen in regional infrasound data or cloudy satellite observations. Low-level seismic activity was elevated just before and after the event. In response to this activity, AVO is raising the Aviation Color Code YELLOW and Alert Level to ADVISORY.

Great Sitkin is monitored with a local real-time seismic network, which will typically allow AVO to detect changes in unrest that may lead to an explosive eruption. Rapid detection of an ash-producing eruption would be accomplished using a combination of seismic, infrasound, lightning, and satellite data.
(12) Volcanic cloud height: n/a
(13) Other volcanic cloud information: Unknown
(14) Remarks: Great Sitkin Volcano is a basaltic andesite volcano that occupies most of the northern half of Great Sitkin Island, a member of the Andreanof Islands group in the central Aleutian Islands. It is located 43 km (26 miles) east of the community of Adak. The volcano is a composite structure consisting of an older dissected volcano and a younger parasitic cone with a 3-km-diameter summit crater. A steep-sided lava dome, emplaced during an eruption in 1974, occupies the center of the crater. Great Sitkin erupted at least three times in the 20th century, most recently in 1974. That eruption produced at least one ash cloud that likely exceeded an altitude of 25,000 ft above sea level. A poorly documented eruption occurred in 1945, also producing a lava dome that was partially destroyed in the 1974 eruption. Within the past 280 years a large explosive eruption produced pyroclastic flows that partially filled the Glacier Creek valley on the southwest flank.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI
dfee1@alaska.edu (907) 322-4085
(16) Next Notice:
2019-05-15 - Pavlof, Aviation Color Code: YELLOW (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20190515/2222Z)
(3) Volcano: Pavlof (VNUM #312030)
(4) Current Color Code: YELLOW
(5) Previous Color Code: GREEN
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 55 deg 25 min W 161 deg 53 min
(9) Area: Alaska Peninsula
(10) Summit Elevation: 8261 ft (2518 m)
(11) Volcanic Activity Summary: Over the past day low-frequency seismic tremor has been observed at Pavlof and web camera observations from this morning showed a vigorous steam plume from the summit. This represents an increase from background activity and we are increasing the the Aviation Color Code and Alert Level to YELLOW/ADVISORY.

This does not mean that an eruption is likely or imminent. However, past eruptions of Pavlof occurred with little or no warning.
(12) Volcanic cloud height: None
(13) Other volcanic cloud information: None
(14) Remarks: Pavlof Volcano is a snow- and ice-covered stratovolcano located on the southwestern end of the Alaska Peninsula about 953 km (592 mi) southwest of Anchorage. The volcano is about 7 km (4.4 mi) in diameter and has active vents on the north and east sides close to the summit. With over 40 historic eruptions, it is one of the most consistently active volcanoes in the Aleutian arc. Eruptive activity is generally characterized by sporadic Strombolian lava fountaining continuing for a several-month period. Ash plumes as high as 49,000 ft ASL have been generated by past eruptions of Pavlof, and during the March 2016 eruption, ash plumes as high as 40,000 feet above sea level were generated and the ash was tracked in satellite data as distant as eastern Canada. The nearest community, Cold Bay, is located 60 km (37 miles) to the southwest of Pavlof.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAF
dfee1@alaska.edu (907) 322-4085
(16) Next Notice:
2019-04-30 - Veniaminof, Aviation Color Code: GREEN (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20190430/2034Z)
(3) Volcano: Veniaminof (VNUM #312070)
(4) Current Color Code: GREEN
(5) Previous Color Code: YELLOW
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 56 deg 11 min W 159 deg 23 min
(9) Area: Alaska Peninsula
(10) Summit Elevation: 8225 ft (2507 m)
(11) Volcanic Activity Summary: Eruptive activity at Veniaminof ceased in early January 2019, and over the past four months indications of unrest have decreased. Therefore AVO is lowering the Aviation Color Code to GREEN and the Volcano Alert Level to NORMAL.

Low-level tremor, slightly elevated surface temperatures and minor steam emissions continue, but are now considered typical for this post-eruptive period. This activity will likely continue for many months.
(12) Volcanic cloud height: None
(13) Other volcanic cloud information: n/a
(14) Remarks:
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI
dfee1@alaska.edu (907) 322-4085
(16) Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at
http://www.avo.alaska.edu
2019-03-27 - Kilauea, Aviation Color Code: GREEN (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20190327/0107Z)
(3) Volcano: Kilauea (VNUM #332010)
(4) Current Color Code: GREEN
(5) Previous Color Code: YELLOW
(6) Source: Hawaiian Volcano Observatory
(7) Notice Number: 2019/H19
(8) Volcano Location: N 19 deg 25 min W 155 deg 17 min
(9) Area: Hawaii
(10) Summit Elevation: 4091 ft (1247 m)
(11) Volcanic Activity Summary: Kīlauea Volcano is quiet. Monitoring data over the past eight months have shown relatively low rates of seismicity, deformation, and gas emission at the summit and East Rift Zone (ERZ) including the area of the 2018 eruption.

Accordingly, the Hawaiian Volcano Observatory (HVO) is lowering the Volcano Alert Level for ground-based hazards from ADVISORY to NORMAL. This means the volcano is at a non-eruptive, background state. The Aviation Color Code is also being lowered from YELLOW to GREEN.

For definitions of USGS Volcano Alert Levels and Aviation Color Codes, see: https://volcanoes.usgs.gov/vhp/about_alerts.html

Despite this change, some hazardous conditions remain and are described below. Kīlauea remains an active volcano, and it will erupt again. Although we expect clear signs prior to a return to eruption, the time frame of warning may be short. Island of Hawaiʻi residents should be familiar with the long-term hazard map for Kīlauea Volcano and how to stay informed about Kīlauea activity.

Lava flow hazard map for the Island of Hawaiʻi: https://pubs.usgs.gov/mf/1992/2193/
(12) Volcanic cloud height: only minor fume from active areas
(13) Other volcanic cloud information: none at this time
(14) Remarks: Current state of the volcano

Kīlauea Volcano has maintained a low level of non-eruptive unrest since the end of the lower East Rift Zone eruption and summit collapse in early September 2018. The past nearly 8 months without active lava at the surface of the volcano marks the longest time interval without eruption since the 17-month period between November 1979 and April 1982.

The total combined sulfur dioxide (SO2) emission rate from the summit, Puʻu ʻŌʻō, and lower East Rift Zone fissure vents is currently less than 100 tonnes per day, well below pre-2018 levels.

Seismicity remains relatively low and steady across the volcano. Although weekly earthquake counts are elevated above pre-2018 eruption levels, they do not reflect shallowing of magma that typically occurs prior to eruption outbreaks. Most of these earthquakes are aftershocks of the May 4, 2018, magnitude-6.9 Kalapana earthquake, and they will continue at declining rates. Earthquakes such as the March 13, 2019, magnitude-5.5 south flank event reflect ongoing south flank instability and are not a sign of renewed eruption potential.

Ground deformation continues, but at rates below those during the period of major eruptive activity in 2018. Deformation rates on the East Rift Zone and at Kīlauea’s summit are still higher than they were prior to April 2018, but have been slowly decreasing. The middle East Rift Zone between Puʻu ʻŌʻō and Highway 130 continues to show ground motion that likely reflects slow refilling of the deep rift zone. Deformation rates may remain high, as magma entering Kīlauea’s system is stored, rather than erupted. Motion on Kīlauea’s south flank is higher than before May’s magnitude-6.9 earthquake. This motion is consistent with increased sliding on Kīlauea’s décollement fault in a process called “afterslip,” which is expected following a large earthquake.

What is next at Kīlauea Volcano?

Since the early 1800s, when written records of Hawaiian volcanoes began, Kīlauea has had infrequent periods during which no lava erupted. The longest known eruptive pause was in 1935-1952, ending with eruption in the caldera.

Neither this 17-year pause, nor any other shorter pause, followed partial collapse of the caldera such as the collapse that occurred in the summer of 2018.

After partial caldera collapses in 1840 and 1868, lava returned to the caldera within days to a few weeks. The length of the current pause already exceeds those earlier post-collapse pauses.

Following partial caldera collapses, the first eruption outside the caldera took place on the East Rift Zone 17 years after the 1823 collapse, on the Southwest Rift Zone 28 years after the 1840 collapse, and on the Southwest Rift Zone 52 years after the 1868 collapse.

On the basis of these observations, we think it most likely that the next eruption of Kīlauea will take place in the caldera within a few years, and that the next eruption on one of the volcano’s rift zones will be in a decade or longer. This prognosis assumes a return to Kīlauea’s general style of behavior for the past 200 years.

There remains the possibility that Kīlauea’s behavior may return to the dominantly explosive 300 years preceding the early 1800s. Monitoring and ongoing analysis by HVO may be able to determine in advance which style of behavior will eventually prevail, but it is currently too early to tell.

Importantly, current monitoring data do not suggest a return to eruptive activity or summit collapse in the coming months. However, Kīlauea is one of the most active volcanoes in the world, and additional eruptions will occur. Residents should remain informed of the volcano's status, learn about long-term hazards, and understand how alerts and warnings of volcanic activity are distributed.

To receive updates on Kīlauea or other Hawaiian volcanoes, sign up here:
https://volcanoes.usgs.gov/vns2/

For more information please see the HVO web site: https://volcanoes.usgs.gov/volcanoes/kilauea/geo_hist_summary.html

Continuing Hazards

Despite diminished activity on Kīlauea, hazardous conditions remain in the East Rift Zone and at the summit of the volcano.

The lower East Rift Zone and Puʻu ʻŌʻō lava flow fields include large areas of still-warm, rugged, extremely sharp, and unstable lava surfaces that are subject to collapse. During heavy rain, white-out conditions (from steam produced by rainwater interacting with hot rock) could develop on the lava flows leading to dangerous conditions. Recent collapses of the new shoreline are not known to have occurred, but could happen should the new lava sea cliffs become unstable.

SO2 gas emissions have greatly decreased from lower East Rift Zone vents to a level below instrumental detection on area roadways. However, locally higher concentrations of SO2 or H2S (hydrogen sulfide) may persist and residents in downwind areas may, from time to time, notice odors of these gases.

Steaming ground cracks are especially common just west of Highway 130. HVO continues to monitor these cracks periodically for changes and will do so for the foreseeable future. Some of what emanates from these thermal areas is related to decomposition of vegetation and is not degassing magma. Emissions from these cracks are likely to continue for years and may change with atmospheric conditions and wind.

Around fissure 8, thick accumulations of tephra (fragmental volcanic debris) hide underground hazards such as holes, ground cracks, and collapsed houses and water tanks. Winds can pick up glassy and lightweight fragments, including Pele's hair, and carry them downwind. Tephra can irritate eyes, skin, and respiratory systems, so prolonged exposure should be avoided.

At the Kīlauea summit, steep crater walls destabilized by 2018 collapse events and earthquakes may be prone to sudden slumping or rockfalls for years to come, even without further ground shaking. Local concentrations of SO2 or H2S (hydrogen sulfide) remain low but people in downwind areas may from time to time notice odors of these gases. As the water table beneath the caldera adjusts to post-collapse conditions and possibly returns to the area of subsidence, it is possible, but not certain, that hydrothermal explosions could occur.

Kīlauea Volcano, as well as the entire Island of Hawaiʻi, remains an area of ongoing earthquake hazard. Additional aftershocks from the May 4, 2018, magnitude-6.9 earthquake and the March 13, 2019, magnitude-5.5 earthquake are expected, and some could be damaging.

HVO continues to closely monitor incoming geologic, seismic, deformation, and gas data for evidence of significant magma shallowing or pressurization that could mean Kīlauea Volcano’s magmatic system is building toward renewed activity.

From Hawaii County Civil Defense: Hawaii County Civil Defense advises that lava flows and features created by the 2018 eruption are primarily on private property and persons are asked to be respectful and not enter or park on private property.
(15) Contacts: askHVO@usgs.gov
(16) Next Notice: The Hawaiian Volcano Observatory (HVO) continues to closely monitor Kīlauea's seismicity, deformation, and gas emissions for any sign of reactivation. HVO will continue to issue weekly Kīlauea updates on Tuesdays until further notice.
2019-02-25 - Great Sitkin, Aviation Color Code: GREEN (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20190225/2030Z)
(3) Volcano: Great Sitkin (VNUM #311120)
(4) Current Color Code: GREEN
(5) Previous Color Code: YELLOW
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 52 deg 4 min W 176 deg 6 min
(9) Area: Aleutians
(10) Summit Elevation: 5709 ft (1740 m)
(11) Volcanic Activity Summary: Earthquake activity at Great Sitkin Volcano has decreased to background levels over the past month. There are no evidence of explosive activity in geophysical data streams or in satellite observations. Thus, AVO is decreasing the Aviation Color Code GREEN and Alert Level to NORMAL.
(12) Volcanic cloud height: n/a
(13) Other volcanic cloud information: n/a
(14) Remarks:
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Pavel Izbekov, Acting Coordinating Scientist, UAFGI
peizbekov@alaska.edu (907) 322-4085
(16) Next Notice:
2019-02-25 - Cleveland, Aviation Color Code: YELLOW (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20190225/2024Z)
(3) Volcano: Cleveland (VNUM #311240)
(4) Current Color Code: YELLOW
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 52 deg 49 min W 169 deg 56 min
(9) Area: Aleutians
(10) Summit Elevation: 5676 ft (1730 m)
(11) Volcanic Activity Summary: Satellite data from 22 February 2019 and regional seismic and infrasound data show no evidence of eruptive activity. Thus, AVO is lowering the Aviation Color Code to YELLOW and the Volcano Alert Level to ADVISORY.

Future explosions at Cleveland are likely. They occur without warning and typically produce relatively small volcanic ash clouds that dissipate within hours; however, more significant ash emissions are possible.
(12) Volcanic cloud height: None
(13) Other volcanic cloud information: n/a
(14) Remarks: Cleveland volcano does not have any functioning equipment near the volcano, which restricts AVO's ability to detect precursory unrest that may lead to an explosive eruption. Rapid detection of an ash-producing eruption may be possible using a combination of regional seismic, infrasound, lightning, and satellite data.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Pavel Izbekov, Acting Coordinating Scientist, UAFGI
peizbekov@alaska.edu (907) 322-4085
(16) Next Notice:
2019-02-02 - Dutton, Aviation Color Code: UNASSIGNED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20190202/0031Z)
(3) Volcano: Dutton (VNUM #312011)
(4) Current Color Code: UNASSIGNED
(5) Previous Color Code:
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 55 deg 11 min W 162 deg 16 min
(9) Area: Alaska Peninsula
(10) Summit Elevation: 4833 ft (1473 m)
(11) Volcanic Activity Summary: AVO can no longer seismically monitor Mount Dutton volcano due to the lack of a functioning seismic network there. As a result, AVO is unable to (1) assess whether Dutton may be building towards an eruption and (2) quickly confirm or dismiss reports of activity at the volcano.

Because Dutton is no longer seismically monitored, it will move from volcano alert level Normal and aviation color code Green to "unassigned." As at other volcanoes without real-time seismic networks, AVO will continue to use satellite data, regional infrasound, lightning, and reports from pilots and ground observers to detect signs of eruptive activity.
(12) Volcanic cloud height: Unknown
(13) Other volcanic cloud information: Unknown
(14) Remarks: Mount Dutton is located near the tip of the Alaska Peninsula and lies jointly within the Izembek Wilderness Area and the Alaska Peninsula Wildlife Refuge. Dutton is a snow- and ice-covered stratovlocano which rises to an elevation of 4833 feet. Although it has no historic eruptive activity, intense earthquake swarms occurred at the volcano in 1984 and 1988. Dutton is located 14 km (9 miles) north of King Cove and 30 km (19 miles) east of Cold Bay.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jessica Larsen, Acting Coordinating Scientist, UAFGI
jflarsen@alaska.edu (907) 322-4085
(16) Next Notice:
2019-01-17 - Cleveland, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20190117/2025Z)
(3) Volcano: Cleveland (VNUM #311240)
(4) Current Color Code: ORANGE
(5) Previous Color Code: YELLOW
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2019/A53
(8) Volcano Location: N 52 deg 49 min W 169 deg 56 min
(9) Area: Aleutians
(10) Summit Elevation: 5676 ft (1730 m)
(11) Volcanic Activity Summary: Satellite data show that starting around 12 January, a new and growing lava dome is present in Cleveland's summit crater. Thus, AVO is raising the Aviation Color Code to ORANGE and the Volcano Alert Level to WATCH.

The presence of the lava dome may increase the likelihood of explosive activity at the volcano. Explosions at Cleveland usually occur without warning and typically produce relatively small volcanic ash clouds that dissipate within hours; however, more significant ash emissions are possible.
(12) Volcanic cloud height: None
(13) Other volcanic cloud information: n/a
(14) Remarks: Cleveland volcano is monitored by only one seismic station, which restricts AVO's ability to detect precursory unrest that may lead to an explosive eruption. Rapid detection of an ash-producing eruption may be possible using a combination of seismic, infrasound, lightning, and satellite data.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Pavel Izbekov, Acting Coordinating Scientist, UAFGI
peizbekov@alaska.edu (907) 322-4085
(16) Next Notice:
2019-01-07 - Cleveland, Aviation Color Code: YELLOW (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20190107/2146Z)
(3) Volcano: Cleveland (VNUM #311240)
(4) Current Color Code: YELLOW
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 52 deg 49 min W 169 deg 56 min
(9) Area: Aleutians
(10) Summit Elevation: 5676 ft (1730 m)
(11) Volcanic Activity Summary: The last detected explosive activity at Cleveland volcano occurred December 29, 2018 UTC (December 28 local time). We have no evidence of significant eruptive activity since that time. Thus, AVO is lowering the Aviation Color Code to YELLOW and the Volcano Alert Level to ADVISORY.

Future explosive activity is likely, and explosions usually occur without warning. Explosions from Cleveland typically produce relatively small volcanic ash clouds that dissipate within hours; however, more significant ash emissions are possible.

Cleveland volcano is monitored by only one seismic station, which restricts AVO's ability to detect precursory unrest that may lead to an explosive eruption. Rapid detection of an ash-producing eruption may be possible using a combination of seismic, infrasound, lightning, and satellite data.
(12) Volcanic cloud height: None
(13) Other volcanic cloud information: n/a
(14) Remarks:
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI
dfee1@alaska.edu (907) 322-4085
(16) Next Notice:
2019-01-04 - Veniaminof, Aviation Color Code: YELLOW (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20190104/1953Z)
(3) Volcano: Veniaminof (VNUM #312070)
(4) Current Color Code: YELLOW
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2019/A10
(8) Volcano Location: N 56 deg 11 min W 159 deg 23 min
(9) Area: Alaska Peninsula
(10) Summit Elevation: 8225 ft (2507 m)
(11) Volcanic Activity Summary: Eruptive activity at Veniaminof has paused or stopped over the past week. Therefore AVO is lowering the Aviation Color Code to YELLOW and the Volcano Alert Level to ADVISORY. Seismic events continue, indicative of continued unrest.
(12) Volcanic cloud height: None
(13) Other volcanic cloud information: Unknown
(14) Remarks: Pauses in eruptive activity are common at Veniaminof and resumed lava effusion and/or ash emissions could resume at any time without significant seismic precursors.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI
dfee1@alaska.edu (907) 322-4085
(16) Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at
http://www.avo.alaska.edu
2018-12-29 - Cleveland, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20181229/0354Z)
(3) Volcano: Cleveland (VNUM #311240)
(4) Current Color Code: ORANGE
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 52 deg 49 min W 169 deg 56 min
(9) Area: Aleutians
(10) Summit Elevation: 5676 ft (1730 m)
(11) Volcanic Activity Summary: Local seismic sensors recorded a short-lived explosion today at 3:17 UTC December 29 (18:17 AKST December 28). A pilot report indicates an ash cloud to 17,000 ft asl. Local winds are from the west.

Explosions from Cleveland typically produce relatively small volcanic ash clouds that dissipate within hours; however, more significant ash emissions are possible.

Cleveland volcano is monitored with a limited real-time seismic network, which inhibits AVO's ability to detect precursory unrest that may lead to an explosive eruption. Rapid detection of an ash-producing eruption may be possible using a combination of seismic, infrasound, lightning, and satellite data.
(12) Volcanic cloud height: 17,000 ft asl
(13) Other volcanic cloud information: winds are from west
(14) Remarks:
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

David Fee, Acting Coordinating Scientist, UAFGI
dfee1@alaska.edu (907) 322-4085
(16) Next Notice:
2018-12-19 - Semisopochnoi, Aviation Color Code: UNASSIGNED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20181219/2035Z)
(3) Volcano: Semisopochnoi (VNUM #311060)
(4) Current Color Code: UNASSIGNED
(5) Previous Color Code: YELLOW
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 51 deg 55 min E 179 deg 35 min
(9) Area: Aleutians
(10) Summit Elevation: 2625 ft (800 m)
(11) Volcanic Activity Summary: No eruptive activity has been detected at Semisopochnoi since November 1 when a satellite link for transmitting seismic data failed. Since that time, no changes have been observed in satellite data, and no explosions have been detected from the Adak Island infrasound array; the last explosion detected by infrasound was October 31.

AVO is lowering the Aviation Color Code to UNASSIGNED and Alert Level to UNASSIGNED for Semisopochnoi due to the lack of evidence for ongoing eruptive activity. Seismic unrest may be continuing undetected. Pauses in eruptions lasting weeks to months are known to occur during volcanic eruptions. A return to eruptive activity may occur with little or no warning.
(12) Volcanic cloud height: No cloud observed
(13) Other volcanic cloud information: No cloud observed
(14) Remarks: The seismic monitoring network for Semisopochnoi has been offline since November 1, but if atmospheric conditions permit an infrasound array on Adak Island may detect explosion signals from Semisopochnoi with a 13 minute delay. Semisopochnoi is also monitored remotely with satellite observations and lightning sensors.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497


David Fee, Acting Coordinating Scientist, UAFGI
dfee1@alaska.edu (907) 322-4085
(16) Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at
http://www.avo.alaska.edu
2018-12-12 - Cleveland, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20181212/2121Z)
(3) Volcano: Cleveland (VNUM #311240)
(4) Current Color Code: ORANGE
(5) Previous Color Code: YELLOW
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 52 deg 49 min W 169 deg 56 min
(9) Area: Aleutians
(10) Summit Elevation: 5676 ft (1730 m)
(11) Volcanic Activity Summary: Local seismic sensors recorded a small explosion today at 20:53 UTC (11:53 AKST). No ash cloud has yet been detected in satellite imagery. No other significant activity was detected.

Explosions from Cleveland typically produce relatively small volcanic ash clouds that dissipate within hours; however, more significant ash emissions are possible.

Cleveland volcano is monitored with a limited real-time seismic network, which inhibits AVO's ability to detect precursory unrest that may lead to an explosive eruption. Rapid detection of an ash-producing eruption may be possible using a combination of seismic, infrasound, lightning, and satellite data.
(12) Volcanic cloud height: Not known
(13) Other volcanic cloud information: n/a
(14) Remarks:
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Pavel Izbekov, Acting Coordinating Scientist, UAFGI
peizbekov@alaska.edu (907) 322-4085
(16) Next Notice:
2018-11-22 - Veniaminof, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20181122/2005Z)
(3) Volcano: Veniaminof (VNUM #312070)
(4) Current Color Code: ORANGE
(5) Previous Color Code: RED
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 56 deg 11 min W 159 deg 23 min
(9) Area: Alaska Peninsula
(10) Summit Elevation: 8225 ft (2507 m)
(11) Volcanic Activity Summary: Ash emissions at Veniaminof have decreased since yesterday afternoon but continue at lower levels. Therefore AVO is lowering the Aviation Color Code to ORANGE and the Volcano Alert Level to WATCH.

Please reference https://www.weather.gov/aawu/sigmets for updated guidance on airborne ash hazards from the National Weather Service.
(12) Volcanic cloud height: Up to ~10,000 ft
(13) Other volcanic cloud information: Continuous low-level ash emissions observed in webcam
(14) Remarks: Ash fall remains possible in nearby communities. National Weather Service information about ashfall is available here: https://www.weather.gov/afc/
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI
dfee1@alaska.edu (907) 322-4085
(16) Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at
http://www.avo.alaska.edu
2018-11-21 - Semisopochnoi, Aviation Color Code: YELLOW (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20181121/2059Z)
(3) Volcano: Semisopochnoi (VNUM #311060)
(4) Current Color Code: YELLOW
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 51 deg 55 min E 179 deg 35 min
(9) Area: Aleutians
(10) Summit Elevation: 2625 ft (800 m)
(11) Volcanic Activity Summary: No eruptive activity has been detected at Semisopochnoi since November 1 when a satellite link for transmitting seismic data failed. Since that time, no changes have been observed in satellite data, and no explosions have been detected from the Adak Island infrasound array; the last explosion detected by infrasound was October 31.

AVO is lowering the Aviation Color Code and Alert Level to Yellow/Advisory for Semisopochnoi due to the lack of evidence for ongoing eruptive activity. Seismic unrest may be continuing undetected. Pauses in eruptions lasting weeks to months are known to occur during volcanic eruptions. A return to eruptive activity may occur with little or no warning.

(12) Volcanic cloud height: No cloud observed
(13) Other volcanic cloud information: No cloud observed
(14) Remarks: The seismic monitoring network for Semisopochnoi has been offline since November 1, but if atmospheric conditions permit an infrasound array on Adak Island may detect explosion signals from Semisopochnoi with a 13 minute delay. Semisopochnoi is also monitored remotely with satellite observations and lightning sensors.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI
dfee1@alaska.edu (907) 322-4085
(16) Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at
http://www.avo.alaska.edu
2018-11-21 - Veniaminof, Aviation Color Code: RED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20181121/1915Z)
(3) Volcano: Veniaminof (VNUM #312070)
(4) Current Color Code: RED
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 56 deg 11 min W 159 deg 23 min
(9) Area: Alaska Peninsula
(10) Summit Elevation: 8225 ft (2507 m)
(11) Volcanic Activity Summary: Overnight, ash emissions from Veniaminof increased significantly, generating a plume up to 15,000 ft asl and extending for more than 150 miles to the SE. This morning observers in Perryville and webcam views indicated continuous ash emissions. This activity is a significant increase from the past month and AVO is raising the Aviation Color Code to Red and the Volcano Alert Level to Warning.

A SIGMET warning for aviation has been issued by the National Weather Service. Please reference https://www.weather.gov/aawu/sigmets for updated guidance on airborne ash hazards.
(12) Volcanic cloud height: Up to ~15,000 ft
(13) Other volcanic cloud information: Continuous ash emissions observed in webcam
(14) Remarks: Ash fall is possible in nearby communities. The National Weather Service Anchorage Forecast Office will issue an advisory if this is expected to occur.
https://www.weather.gov/afc/
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI
dfee1@alaska.edu (907) 322-4085
(16) Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at
http://www.avo.alaska.edu
2018-10-26 - Semisopochnoi, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20181026/0535Z)
(3) Volcano: Semisopochnoi (VNUM #311060)
(4) Current Color Code: ORANGE
(5) Previous Color Code: YELLOW
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 51 deg 55 min E 179 deg 35 min
(9) Area: Aleutians
(10) Summit Elevation: 2625 ft (800 m)
(11) Volcanic Activity Summary: Strong seismic tremor from Semisopochnoi consistent with an eruption began at 4:47 UTC (20:47 AKDT) and is currently diminishing. Satellite data through 5:00 UTC (21:00 AKDT) show a small ash cloud at about 12,000 ft asl.

AVO is raising the Aviation Color Code and Alert Level to Orange/Watch for Semisopochnoi.
(12) Volcanic cloud height: about 12,000 ft asl
(13) Other volcanic cloud information: winds toward the southeast
(14) Remarks: Semisopochnoi is monitored with an on-island seismic network, and remotely by satellite and lightning sensors. An infrasound array on Adak Island could detect explosive emissions from Semisopochnoi with a 13 minute delay if atmospheric conditions permit.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI
dfee1@alaska.edu (907) 322-4085
(16) Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at
http://www.avo.alaska.edu
2018-10-12 - Semisopochnoi, Aviation Color Code: YELLOW (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20181012/1945Z)
(3) Volcano: Semisopochnoi (VNUM #311060)
(4) Current Color Code: YELLOW
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 51 deg 55 min E 179 deg 35 min
(9) Area: Aleutians
(10) Summit Elevation: 2625 ft (800 m)
(11) Volcanic Activity Summary: Recent satellite observations and a lack of seismic tremor over the past week indicate eruptive activity at Semisopochnoi has paused. Thus we are lowering the Aviation Color Code to YELLOW and the Volcano Alert Level to ADVISORY. Although seismic tremor is currently absent at Semisopochnoi, discrete earthquake activity remains above background levels.

Pauses in eruptive activity lasting for weeks to months are known to occur during volcanic eruptions. A return to eruptive activity remains a possibility at Semisopochnoi that could occur with little or no warning. AVO will continue to monitor the volcano closely.
(12) Volcanic cloud height: Unknown
(13) Other volcanic cloud information: Unknown
(14) Remarks: Semisopochnoi is monitored with an on-island seismic network, and remotely by satellite and lightning sensors. An infrasound array on Adak Island could detect explosive emissions from Semisopochnoi with a 13 minute delay if atmospheric conditions permit.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI
dfee1@alaska.edu (907) 322-4085
(16) Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at
http://www.avo.alaska.edu
2018-10-05 - Kilauea, Aviation Color Code: YELLOW (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20181005/1847Z)
(3) Volcano: Kilauea (VNUM #332010)
(4) Current Color Code: YELLOW
(5) Previous Color Code: ORANGE
(6) Source: Hawaiian Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 19 deg 25 min W 155 deg 17 min
(9) Area: Hawaii
(10) Summit Elevation: 4091 ft (1247 m)
(11) Volcanic Activity Summary: It has been 30 days since lava has been active at the surface of Kīlauea Volcano. HVO monitoring shows low rates of seismicity, steady, relatively low rates of deformation across the volcano, and only minor gas emission at the summit and East Rift Zone (ERZ). These observations indicate that resumption of eruption or summit collapse is unlikely in the near-term.

Accordingly, HVO is lowering the Volcano Alert Level for ground based hazards from WATCH to ADVISORY. This means volcanic activity has decreased significantly but continues to be closely monitored for renewed activity. The Aviation Color Code is also being lowered from ORANGE to YELLOW.

Hazards are still present in the lower East Rift Zone (LERZ) eruption area and at the Kīlauea summit. Residents and visitors near recently active fissures and lava flows should stay informed, heed Hawaii County Civil Defense warnings, and be prepared, if necessary, to self-evacuate in the unlikely event of renewed activity. Please note that Hawaii County maintains a closure of the entire flow field and the vents and prohibits access to the area unless authorized through Civil Defense.

Residents are also advised of continuing hazardous conditions described below.

For definitions of USGS Volcano Alert Levels and Aviation Color Codes, see: https://volcanoes.usgs.gov/vhp/about_alerts.html
(12) Volcanic cloud height: only minor fume from active areas
(13) Other volcanic cloud information: none at this time
(14) Remarks: Background and Prognosis

Kīlauea Volcano has maintained a low level of activity over the past two months. The last summit collapse was on August 2, 2018. High rates of seismicity and deflationary deformation at the summit stopped abruptly on August 4, coincident with cessation of major eruptive activity in the LERZ. Lava ceased flowing in the upper portion of the fissure 8 channel system by August 6, and ocean entries were inactive in late August. Active lava was last seen inside the fissure 8 cone on September 5. The total sulfur dioxide (SO2) emission rate from the summit, Puʻu ʻŌʻō, and LERZ fissure vents combined is currently less than 300 tonnes per day.

Seismicity remains low across the volcano. Ground deformation continues, but at rates well below those during the period of major eruptive activity this summer. An exception is within the middle East Rift Zone where data show evidence of reinflation between Puʻu ʻŌʻō and Highway 130. One interpretation of this signal is that the rift zone is refilling with magma following withdrawal during the 2018 eruption. An increase in this refilling rate or other change could result in new eruptive vents along any portion of the East Rift Zone.

While it is impossible to say with certainty what Kīlauea will do next, current monitoring data do not suggest a return to eruptive activity or summit collapse in the near term. HVO continues to closely monitor incoming geologic, seismic, deformation, and gas data for evidence of significant magma shallowing or pressurization that could mean the system was building toward renewed activity.

This change in activity marks the first time since 1986 that lava has not been active at Kīlauea’s surface for a period of 30 or more days (The last long pause was 48.5 days between episodes 39 and 40 of the Puʻu ʻŌʻō eruption.) In the past 200 years, the volcano has experienced periods of quiet ranging from months to years with no eruptive activity. However, Kīlauea is one of the most active volcanoes in the world, and additional eruptions will occur. Residents should remain informed of the volcano’s status and learn about long-term hazards. For more information please see the HVO web site: https://volcanoes.usgs.gov/volcanoes/kilauea/geo_hist_summary.html

Continuing Hazards

Despite the diminished activity on Kīlauea, hazardous conditions remain in the ERZ and at the summit of the volcano.

The LERZ and Puʻu ʻŌʻō lava flow fields include large areas of still-hot, rugged, extremely sharp, and unstable lava surfaces that are subject to collapse.

SO2 gas emissions have greatly decreased from LERZ vents to a level below instrumental detection. However, local concentrations of SO2 or H2S may persist and are still reported in downwind areas,and residents may from time to time notice odors of these gasses. Hot cracks degassing at low levels are especially common just west of Highway 130 and HVO will continue to monitor these cracks for changes.

Around fissure 8, thick accumulations of tephra (fragmental volcanic debris) hide underground hazards such as holes and cracks; winds can pick up glassy and lightweight fragments including Pele’s hair and carry them downwind. Tephra can irritate eyes, skin, and respiratory systems, so prolonged exposure should be avoided.

New lava fields at the coast appear relatively stable based on a helicopter overflight on 4 October, however no intensive ground survey of the new coastline has been done. Explosions near the coastline may still occur if sudden collapses expose the hot interiors of new lava flows to cold ocean water. HVO has received no reports that such collapses and/or explosions have occurred, but mariners should operate with caution around the new coastline and contact the U.S. Coast Guard with any questions.

At the Kīlauea summit, rockfalls and ground cracking can still occur with no warning. Steep crater walls destabilized by months of earthquakes will be prone to collapse for weeks or months to come, even without further ground shaking.

As the summit continues to adjust to recent changes, additional, and potentially damaging, earthquakes are possible. Additional aftershocks from the May 4, 2018, magnitude-6.9 earthquake are expected. Hawai’i is prone to earthquakes, so everyone should be prepared for damaging ground shaking at any time.

At the summit, if significant draining of the magma reservoir resumes, more collapse events could occur. Alternatively, resupply of magma to the summit reservoir could lead to explosions or the reappearance of lava in the caldera.

(15) Contacts: askHVO@usgs.gov
(16) Next Notice: The Hawaiian Volcano Observatory (HVO) continues to closely monitor Kīlauea's seismicity, deformation, and gas emissions for any sign of reactivation. As of today, HVO will discontinue daily Kīlauea updates and will issue weekly updates on Tuesdays until further notice. If volcano activity increases, we will elevate the Alert Level for Kīlauea.

2018-09-17 - Semisopochnoi, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20180917/2133Z)
(3) Volcano: Semisopochnoi (VNUM #311060)
(4) Current Color Code: ORANGE
(5) Previous Color Code: YELLOW
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 51 deg 55 min E 179 deg 35 min
(9) Area: Aleutians
(10) Summit Elevation: 2625 ft (800 m)
(11) Volcanic Activity Summary: Elevated seismicity that started yesterday has intensified over the past couple of hours, and a strong tremor signal at 20:49 UTC (12:49 AKDT) suggests that ash emissions may be occurring or are imminent at Semisopochnoi. Thus we are raising the Aviation Color Code to ORANGE and the Volcano Alert Level to WATCH.

Nothing has been detected in satellite, lightning, or infrasound data.
(12) Volcanic cloud height: Unknown
(13) Other volcanic cloud information: Unknown
(14) Remarks: Semisopochnoi is monitored with an on-island seismic network, and remotely by satellite and lightning sensors. An infrasound array on Adak Island could detect explosive emissions from Semisopochnoi with a 13 minute delay if atmospheric conditions permit.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI
dfee1@alaska.edu (907) 322-4085
(16) Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at
http://www.avo.alaska.edu
2018-09-16 - Semisopochnoi, Aviation Color Code: YELLOW (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20180916/1756Z)
(3) Volcano: Semisopochnoi (VNUM #311060)
(4) Current Color Code: YELLOW
(5) Previous Color Code: UNASSIGNED
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 51 deg 55 min E 179 deg 35 min
(9) Area: Aleutians
(10) Summit Elevation: 2625 ft (800 m)
(11) Volcanic Activity Summary: An increase in seismicity beginning 16:31 UTC (08:31 AKDT) on has prompted AVO to raise the Aviation Color Code and Volcano Alert Level to YELLOW/ADVISORY.

There is no clear indication from satellite imagery or regional infrasound data that Semisopochnoi is erupting at this time. AVO will continue to monitor Semisopochnoi seismic data and evaluate satellite images.
(12) Volcanic cloud height: Unknown
(13) Other volcanic cloud information: Unknown
(14) Remarks:
(15) Contacts: Chris Waythomas, Acting Scientist-in-Charge, USGS
cwaythomas@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI
dfee1@alaska.edu (907) 322-4085
(16) Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at
http://www.avo.alaska.edu
2018-09-04 - Veniaminof, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20180904/2109Z)
(3) Volcano: Veniaminof (VNUM #312070)
(4) Current Color Code: ORANGE
(5) Previous Color Code: YELLOW
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 56 deg 11 min W 159 deg 23 min
(9) Area: Alaska Peninsula
(10) Summit Elevation: 8225 ft (2507 m)
(11) Volcanic Activity Summary: Seismic activity remains elevated at Veniaminof. Low-level ash emissions have been observed in web camera images and have been confirmed by observers in Perryville. Thus, AVO is raising the Aviation Color Code to Orange and the Volcano Alert Level to Watch.
(12) Volcanic cloud height: 8000-10,000ft
(13) Other volcanic cloud information: Low-level ash emissions.
(14) Remarks: Mount Veniaminof volcano is an andesitic stratovolcano with an ice-filled 10-km diameter summit caldera located on the Alaska Peninsula, 775 km (480 mi) southwest of Anchorage and 35 km (22 mi) north of Perryville. Veniaminof is one of the largest (~300 cubic km; 77 cubic mi) and most active volcanic centers in the Aleutian Arc and has erupted at least 13 times in the past 200 years. Recent significant eruptions of the volcano occurred in 1993-95, 2005, and 2013. These were Strombolian eruptions that produced lava fountains and minor emissions of ash and gas from the main intracaldera cone. During the 1993-95 activity, a small lava flow was extruded, and in 2013, five small lava flows effused from the intracaldera cone over about five months. Minor ash-producing explosions occurred nearly annually between 2002 and 2010. Previous historical eruptions have produced ash plumes that reached 20,000 ft above sea level (1939 and 1956) and ash fallout that blanketed areas within about 40 km (25 mi) of the volcano (1939).
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAF
dfee1@alaska.edu (907) 322-4085

(16) Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at
http://www.avo.alaska.edu
2018-09-03 - Veniaminof, Aviation Color Code: YELLOW (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20180903/1929Z)
(3) Volcano: Veniaminof (VNUM #312070)
(4) Current Color Code: YELLOW
(5) Previous Color Code: GREEN
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 56 deg 11 min W 159 deg 23 min
(9) Area: Alaska Peninsula
(10) Summit Elevation: 8225 ft (2507 m)
(11) Volcanic Activity Summary: Seismic activity at Veniaminof, indicative of unrest, increased late last night and volcanic tremor is ongoing. Thus, AVO is rasing the Aviation Color Code to Yellow and the Volcano Alert Level to Advisory. There are, however, no signs of eruptive activity at this time.
(12) Volcanic cloud height: Unknown
(13) Other volcanic cloud information: Unknown
(14) Remarks: Mount Veniaminof volcano is an andesitic stratovolcano with an ice-filled 10-km diameter summit caldera located on the Alaska Peninsula, 775 km (480 mi) southwest of Anchorage and 35 km (22 mi) north of Perryville. Veniaminof is one of the largest (~300 cubic km; 77 cubic mi) and most active volcanic centers in the Aleutian Arc and has erupted at least 13 times in the past 200 years. Recent significant eruptions of the volcano occurred in 1993-95, 2005, and 2013. These were Strombolian eruptions that produced lava fountains and minor emissions of ash and gas from the main intracaldera cone. During the 1993-95 activity, a small lava flow was extruded, and in 2013, five small lava flows effused from the intracaldera cone over about five months. Minor ash-producing explosions occurred nearly annually between 2002 and 2010. Previous historical eruptions have produced ash plumes that reached 20,000 ft above sea level (1939 and 1956) and ash fallout that blanketed areas within about 40 km (25 mi) of the volcano (1939).
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAF
dfee1@alaska.edu (907) 322-4085

(16) Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at
http://www.avo.alaska.edu
2018-08-22 - Cleveland, Aviation Color Code: YELLOW (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20180822/1945Z)
(3) Volcano: Cleveland (VNUM #311240)
(4) Current Color Code: YELLOW
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 52 deg 49 min W 169 deg 56 min
(9) Area: Aleutians
(10) Summit Elevation: 5676 ft (1730 m)
(11) Volcanic Activity Summary: The Aviation Color Code is being reduced to Yellow and the Volcano Alert Level to Advisory at Cleveland volcano. Minor explosive activity was last observed in late July and since that time there has been no evidence of lava extrusion in the summit crater. Elevated surface temperatures in the summit crater continue to be observed during periods of clear weather, but are interpreted to be due to hot degassing. This is typical of Cleveland volcano and indicates that low-level unrest continues.

Occasional, short duration explosive activity with minimal to no precursory signals is common at Cleveland volcano, and explosions may occur without warning. Explosions typically produce relatively small volcanic ash clouds that dissipate within hours; however, more significant ash emissions may occur as they have in the past.

Cleveland volcano is monitored by only two seismic stations, which restricts AVO's ability to detect precursory unrest that may lead to an explosive eruption. Rapid detection of an ash-producing eruption may be possible using a combination of seismic, infrasound, lightning, and satellite data.
(12) Volcanic cloud height: None
(13) Other volcanic cloud information: n/a
(14) Remarks:
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jessica Larsen, Acting Coordinating Scientist, UAF
jflarsen@alaska.edu (907) 322-4085

(16) Next Notice:
2018-07-01 - Great Sitkin, Aviation Color Code: YELLOW (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20180701/1837Z)
(3) Volcano: Great Sitkin (VNUM #311120)
(4) Current Color Code: YELLOW
(5) Previous Color Code: GREEN
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 52 deg 4 min W 176 deg 6 min
(9) Area: Aleutians
(10) Summit Elevation: 5709 ft (1740 m)
(11) Volcanic Activity Summary: Earthquake activity at Great Sitkin Volcano has increased above background levels over the past day. Numerous small, shallow earthquakes are occurring beneath the summit at rates as high as 10-20 per hour. It is uncertain if this unrest will lead to any eruptive activity but this remains a possibility given the general degree of unrest at Great Sitkin over the past several months. Thus AVO is raising the Aviation Color Code and Alert Level to YELLOW /ADVISORY.

AVO detected a brief steam and ash explosion at Great Sitkin on June 10, and earthquake activity then declined to background levels over a period of about 2 weeks. Over the past several days, nothing significant has been observed in satellite data and no other signs of unrest have been detected or reported to AVO.

Great Sitkin Volcano is monitored by a five-station seismic network on Great Sitkin Island and with additional seismic stations on the nearby islands of Igitkin, Adak, Kagalaska, and Kanaga. A six-element infrasound array to detect explosions (atmospheric pressure waves) was installed on Adak Island in June, 2017, although it is currently (June 2018) only partly operational. AVO also uses satellite imagery to monitor Great Sitkin Volcano.
(12) Volcanic cloud height: not applicable
(13) Other volcanic cloud information: Unknown
(14) Remarks: Great Sitkin Volcano is a basaltic andesite volcano that occupies most of the northern half of Great Sitkin Island, a member of the Andreanof Islands group in the central Aleutian Islands. It is located 43 km (26 miles) east of the community of Adak. Great Sitkin erupted at least three times in the 20th century, most recently in 1974. That eruption produced at least one ash cloud that likely exceeded an altitude of 25,000 ft above sea level. A poorly documented eruption occurred in 1945, also producing a lava dome that was partially destroyed in the 1974 eruption. A seismic swarm occurred from July 2016 through the end of 2017.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jeff Freymueller, Coordinating Scientist, UAFGI
jfreymueller@alaska.edu (907) 322-4085
(16) Next Notice:
2018-06-27 - Great Sitkin, Aviation Color Code: GREEN (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20180627/1849Z)
(3) Volcano: Great Sitkin (VNUM #311120)
(4) Current Color Code: GREEN
(5) Previous Color Code: YELLOW
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 52 deg 4 min W 176 deg 6 min
(9) Area: Aleutians
(10) Summit Elevation: 5709 ft (1740 m)
(11) Volcanic Activity Summary: Earthquake activity at Great Sitkin Volcano has declined gradually and no further indications of increasing unrest have been observed since AVO detected a brief steam and ash explosion on June 10. For the time being, the volcano has returned to normal background levels of activity and AVO is thus lowering the Aviation Color Code and Alert Level to GREEN/NORMAL.

Great Sitkin Volcano is monitored by a five-station seismic network on Great Sitkin Island and with additional seismic stations on the nearby islands of Igitkin, Adak, Kagalaska, and Kanaga. A six-element infrasound array to detect explosions (atmospheric pressure waves) was installed on Adak Island in June, 2017, although it is currently (June 2018) only partly operational. AVO also uses satellite imagery to monitor Great Sitkin Volcano.
(12) Volcanic cloud height: not applicable
(13) Other volcanic cloud information: Unknown
(14) Remarks: Great Sitkin Volcano is a basaltic andesite volcano that occupies most of the northern half of Great Sitkin Island, a member of the Andreanof Islands group in the central Aleutian Islands. It is located 43 km (26 miles) east of the community of Adak. Great Sitkin erupted at least three times in the 20th century, most recently in 1974. That eruption produced at least one ash cloud that likely exceeded an altitude of 25,000 ft above sea level. A poorly documented eruption occurred in 1945, also producing a lava dome that was partially destroyed in the 1974 eruption. A seismic swarm occurred from July 2016 through the end of 2017.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jeff Freymueller, Coordinating Scientist, UAFGI
jfreymueller@alaska.edu (907) 322-4085
(16) Next Notice:
2018-06-26 - Cleveland, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20180626/2107Z)
(3) Volcano: Cleveland (VNUM #311240)
(4) Current Color Code: ORANGE
(5) Previous Color Code: YELLOW
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 52 deg 49 min W 169 deg 56 min
(9) Area: Aleutians
(10) Summit Elevation: 5676 ft (1730 m)
(11) Volcanic Activity Summary: Satellite observations of Cleveland Volcano on June 25, 2018 indicate the presence of a small circular lava flow, about 80 meters in diameter, covering the floor of the summit crater. Geophysical monitoring data from Cleveland Volcano has been unavailable since early yesterday afternoon and thus it is unknown if the effusion of lava within the crater generated detectable seismicity or infrasound. However, the presence of a lava flow over the active vent increases the possibility of a vent clearing explosion over the coming days to weeks and thus AVO is raising the Aviation Color Code and Volcano Alert Level to ORANGE/WATCH. The last detected explosive activity at Cleveland volcano occurred May 5, 2018 UTC (May 4 local time).

Occasional, short duration explosive activity with minimal to no precursory signals is common at Cleveland Volcano, and explosions may occur without warning. Explosions typically produce relatively small volcanic ash clouds that dissipate within hours; however, more significant ash emissions may occur as they have in the past.

Cleveland volcano is monitored by only two seismic stations, which restricts AVO's ability to detect precursory unrest that may lead to an explosive eruption. Rapid detection of an ash-producing eruption may be possible using a combination of seismic, infrasound, lightning, and satellite data.
(12) Volcanic cloud height: None
(13) Other volcanic cloud information: n/a
(14) Remarks:
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jeff Freymueller, Coordinating Scientist, UAFGI
jfreymueller@alaska.edu (907) 322-4085
(16) Next Notice:
2018-06-25 - Kilauea, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20180625/0635Z)
(3) Volcano: Kilauea (VNUM #332010)
(4) Current Color Code: ORANGE
(5) Previous Color Code: RED
(6) Source: Hawaiian Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 19 deg 25 min W 155 deg 17 min
(9) Area: Hawaii
(10) Summit Elevation: 4091 ft (1247 m)
(11) Volcanic Activity Summary: Kīlauea Volcano Summit

Episodic collapse of Kīlauea Volcano’s caldera floor continues, at times accompanied by bursts of small amounts of volcanic ash. The most recent of these occurred today at 4:12 pm.

Since late May, these collapse/explosion events have rarely produced significant ash plumes rising more than 10,000 feet above sea level where they can pose a significant hazard to aviation. For this reason, HVO is reducing the aviation color code from RED to ORANGE.

Collapse/explosion events that may produce ash plumes are expected to continue as long as subsidence is occurring at the volcano’s summit. At any time, activity could intensify producing more ash and higher ash plumes. During these events, ash may be transported downwind to impact communities.

For forecasts of where ash would fall under forecast wind conditions, please consult the Ash3D model output here: https://volcanoes.usgs.gov/observatories/hvo/ash_information.html

Information on volcanic ash hazards and how to prepare for ash fall maybe found at http://www.ivhhn.org/information#ash (health impacts) OR https://volcanoes.usgs.gov/volcanic_ash/ (other impacts).

Sulfur dioxide emissions from the volcano's summit have dropped to levels below those measured during the high stand of the summit lava lake. Air quality in the summit area is, however, impacted by emissions from the Lower East Rift Zone. Information on sulfur dioxide and vog impacts and how to protect yourself from vog may be found here: https://vog.ivhhn.org/

Kīlauea Volcano Lower East Rift Zone

Eruption of lava and gas from the lower East Rift Zone (LERZ) continues into its seventh week. The eruption remains hazardous and therefore HVO is maintaining alert level WARNING.

The fissure 8 cone continues to feed a lava flow reaching the ocean at the Kapoho area coastline. Short-lived overflows of lava from an established channel occur periodically but generally do not travel beyond the existing flow field.

Pele's hair and other lightweight volcanic glass fragments from the lava fountain at fissure 8 continue to fall downwind of the fissure, dusting the ground within a few hundred meters (yards) of the vent. High winds may waft lighter particles to greater distances. Residents are urged to minimize exposure to these volcanic particles, which can cause skin and eye irritation similar to volcanic ash.

The most recent map of lava flows can be found at https://volcanoes.usgs.gov/volcanoes/kilauea/multimedia_maps.html

Volcanic gas emissions remain very high in the Lower East Rift Zone. Shifting wind conditions can bring VOG to nearly all of the Island of Hawaii. VOG information can be found at https://vog.ivhhn.org/

The ocean entry is a hazardous area. Interaction between lava and ocean water can produce sudden explosions of dangerous debris and steam. The growing lava delta is unstable and can slide into the sea without warning. Additionally, the interaction of lava with the ocean creates a towering plume of "laze", a corrosive seawater plume laden with hydrochloric acid and fine volcanic particles that can irritate the skin, eyes, and lungs.

Additional ground cracking and outbreaks of lava in the area of the active fissures are possible. Residents downslope of the region of fissure vents should remain informed and heed all Hawaii County Civil Defense messages and warnings.


(12) Volcanic cloud height: No cloud at this time.
(13) Other volcanic cloud information: Unknown
(14) Remarks:
(15) Contacts: askHVO@usgs.gov
(16) Next Notice: Additional notices will be issued should activity change significantly.

2018-06-21 - Mauna Loa, Aviation Color Code: GREEN (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20180621/2346Z)
(3) Volcano: Mauna Loa (VNUM #332020)
(4) Current Color Code: GREEN
(5) Previous Color Code: YELLOW
(6) Source: Hawaiian Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 19 deg 28 min W 155 deg 36 min
(9) Area: Hawaii
(10) Summit Elevation: 13681 ft (4170 m)
(11) Volcanic Activity Summary: HVO seismic and deformation monitoring networks have been recording near background levels of seismicity and ground motion at Mauna Loa Volcano for at least the last six months. These observations indicate that the volcano is no longer at an elevated level of activity. Accordingly, HVO is dropping the Mauna Loa alert level to NORMAL and the aviation color code to GREEN.

HVO continues to monitor the volcano closely and will report any significant changes.

Stay informed about Mauna Loa by following volcano updates and tracking current monitoring data on the HVO web page (http://hvo.wr.usgs.gov/activity/maunaloastatus.php) or by signing up to receive updates by email at this site: http://volcanoes.usgs.gov/vns/
(12) Volcanic cloud height: Unknown
(13) Other volcanic cloud information: Unknown
(14) Remarks: From 2014 through much of 2017, HVO seismic stations recorded variable, but overall elevated rates of shallow, small-magnitude earthquakes beneath Mauna Loa's summit, upper Southwest Rift Zone, and west flank. During that same time period, HVO measured ground deformation consistent with input of magma into the volcano's shallow magma storage system.

These observations indicated that volcano was not at background levels of activity and the volcano alert level was raised to ADVISORY and the aviation color code to YELLOW in September 2015. It was noted at the time that the increase in alert level did not mean that an eruption was imminent or that progression to an eruption was certain. Indeed, this episode of unrest lasted several years without progressing to an eruption, similar to the period of unrest from 2004 to 2009.

Since late 2017, rates of earthquake occurrence and of ground motion related to inflation of shallow magma reservoirs have slowed to near background levels.

Seismicity has continued to be low during the current activity on Kīlauea volcano. Recent motions recorded by GPS instruments on Mauna Loa are due to the M6.9 Kīlauea south flank earthquake on May 4, 2018 and subsidence at the summit Kīlauea Volcano. None of the activity on Kīlauea volcano has had a detectable effect on Mauna Loa’s magmatic system.

Background:

Mauna Loa is the largest active volcano on Earth. Eruptions typically start at the summit and, within minutes to months of eruption onset, about half of the eruptions migrate into either the Northeast or Southwest Rift Zones. Since 1843, the volcano has erupted 33 times with intervals between eruptions ranging from months to decades. Mauna Loa last erupted 34 years ago, in 1984.

Mauna Loa eruptions tend to produce voluminous, fast-moving lava flows that can impact communities on the east and west sides of the Island of Hawai`i. Since the mid-19th century, the city of Hilo in east Hawai'i has been threatened by seven Mauna Loa lava flows. Mauna Loa lava flows have reached the south and west coasts of the island eight times: 1859, 1868, 1887, 1926, 1919, and three times in 1950.
(15) Contacts: askHVO@usgs.gov
(16) Next Notice: With the downgrade to NORMAL/GREEN, HVO will suspend weekly updates on Mauna Loa. Instead, updates will be issued monthly. Should volcanic activity change significantly a new VAN will be issued. Regularly scheduled updates are posted at http://hvo.wr.usgs.gov
2018-06-10 - Great Sitkin, Aviation Color Code: YELLOW (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20180610/2126Z)
(3) Volcano: Great Sitkin (VNUM #311120)
(4) Current Color Code: YELLOW
(5) Previous Color Code: GREEN
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 52 deg 4 min W 176 deg 6 min
(9) Area: Aleutians
(10) Summit Elevation: 5709 ft (1740 m)
(11) Volcanic Activity Summary: Earthquake activity at Great Sitkin Volcano has been elevated over the past five days, and earlier today at 11:39 AKDT (19:39 UTC), a signal that may represent a short-lived steam explosion was detected by seismic data. AVO is thus raising the Aviation Color Code and Alert Level to YELLOW/ADVISORY.

Great Sitkin Volcano is monitored by a five-station seismic network on Great Sitkin Island and with additional seismic stations on the nearby islands of Igitkin, Adak, Kagalaska, and Kanaga. A six-element infrasound array to detect explosions (atmospheric pressure waves) was installed on Adak Island in June, 2017, although it is currently (June 2018) only partly operational. AVO also uses satellite imagery to monitor Great Sitkin Volcano.
(12) Volcanic cloud height: not applicable
(13) Other volcanic cloud information: Unknown
(14) Remarks: Great Sitkin Volcano is a basaltic andesite volcano that occupies most of the northern half of Great Sitkin Island, a member of the Andreanof Islands group in the central Aleutian Islands. It is located 43 km (26 miles) east of the community of Adak. Great Sitkin erupted at least three times in the 20th century, most recently in 1974. That eruption produced at least one ash cloud that likely exceeded an altitude of 25,000 ft above sea level. A poorly documented eruption occurred in 1945, also producing a lava dome that was partially destroyed in the 1974 eruption. A seismic swarm occurred from July 2016 through the end of 2017.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

David Fee, Acting Coordinating Scientist, UAFGI
dfee1@alaska.edu (907) 322-4085
(16) Next Notice:
2018-05-17 - Kilauea, Aviation Color Code: RED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20180517/1633Z)
(3) Volcano: Kilauea (VNUM #332010)
(4) Current Color Code: RED
(5) Previous Color Code: RED
(6) Source: Hawaiian Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 19 deg 25 min W 155 deg 17 min
(9) Area: Hawaii
(10) Summit Elevation: 4091 ft (1247 m)
(11) Volcanic Activity Summary: At about 0415 this morning, an explosion from the Overlook vent within Halemaumau crater at Kilauea Volcano's summit produced a volcanic cloud that reaches as high as 30,000 ft asl and drifted northeast. Continued emissions from the crater are reaching as high as 12,000 ft asl.

At any time, activity may again become more explosive, increasing the intensity of ash production and producing ballistic projectiles near the vent.

Resource on volcanic ash hazards: https://volcanoes.usgs.gov/volcanic_ash/

Resource on vog: https://vog.ivhhn.org/

Current NWS information on ashfall: http://www.prh.noaa.gov/hnl/watchwarn/
(12) Volcanic cloud height: up to 30,000 ft asl
(13) Other volcanic cloud information: Drifting generally northeast
(14) Remarks: Photos of this activity may be found here:

https://volcanoes.usgs.gov/volcanoes/kilauea/kilauea_multimedia_15.html
(15) Contacts: askHVO@usgs.gov
(16) Next Notice: Additional notices will be issued should activity change significantly.
Consult the National Weather Service for specific Ashfall notifications:http://www.prh.noaa.gov/hnl/
2018-05-15 - Kilauea, Aviation Color Code: RED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20180515/2323Z)
(3) Volcano: Kilauea (VNUM #332010)
(4) Current Color Code: RED
(5) Previous Color Code: ORANGE
(6) Source: Hawaiian Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 19 deg 25 min W 155 deg 17 min
(9) Area: Hawaii
(10) Summit Elevation: 4091 ft (1247 m)
(11) Volcanic Activity Summary: As of early this morning, eruption of ash from the Overlook vent within Halemaumau crater at Kilauea Volcano's summit has generally increased in intensity. Ash has been rising nearly continuously from the vent and drifting downwind to the southwest. Ashfall and vog (volcanic air pollution) has been reported in Pahala, about 18 miles downwind. NWS radar and pilot reports indicate the top of the ash cloud is as high as 10,000 to 12,000 feet above sea level, but this may be expected to vary depending on the vigor of activity and wind conditions.

Ash emission from the Kilauea summit vent will likely be variable with periods of increased and decreased intensity depending on the occurrence of rockfalls into the vent and other changes within the vent.

At any time, activity may become more explosive, increasing the intensity of ash production and producing ballistic projectiles near the vent.

Resource on volcanic ash hazards: https://volcanoes.usgs.gov/volcanic_ash/

Resource on vog: https://vog.ivhhn.org/
(12) Volcanic cloud height: 10,000 - 12,000 feet
(13) Other volcanic cloud information: Drifting generally southwest with tradewinds.
(14) Remarks: Photos of this activity may be found here:

https://volcanoes.usgs.gov/volcanoes/kilauea/kilauea_multimedia_15.html
(15) Contacts: askHVO@usgs.gov
(16) Next Notice: Additional notices will be issued should activity change significantly.
Consult the National Weather Service for specific Ashfall notifications:http://www.prh.noaa.gov/hnl/
2018-05-06 - Cleveland, Aviation Color Code: YELLOW (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20180506/2016Z)
(3) Volcano: Cleveland (VNUM #311240)
(4) Current Color Code: YELLOW
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 52 deg 49 min W 169 deg 56 min
(9) Area: Aleutians
(10) Summit Elevation: 5676 ft (1730 m)
(11) Volcanic Activity Summary: The last detected explosive activity at Cleveland volcano occurred May 5, 2018 UTC (May 4 local time). We have no evidence of significant eruptive activity since that time. Thus, AVO is lowering the Aviation Color Code to YELLOW and the Volcano Alert Level to ADVISORY.

Future explosive activity is likely, and explosions usually occur without warning. Explosions from Cleveland typically produce relatively small volcanic ash clouds that dissipate within hours; however, more significant ash emissions are possible.

Cleveland volcano is monitored by only two seismic stations, which restricts AVO's ability to detect precursory unrest that may lead to an explosive eruption. Rapid detection of an ash-producing eruption may be possible using a combination of seismic, infrasound, lightning, and satellite data.
(12) Volcanic cloud height: None
(13) Other volcanic cloud information: n/a
(14) Remarks:
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jessica Larsen, Acting Coordinating Scientist, UAF
jflarsen@alaska.edu (907) 322-4085
(16) Next Notice:
2018-05-05 - Cleveland, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20180505/0712Z)
(3) Volcano: Cleveland (VNUM #311240)
(4) Current Color Code: ORANGE
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 52 deg 49 min W 169 deg 56 min
(9) Area: Aleutians
(10) Summit Elevation: 5676 ft (1730 m)
(11) Volcanic Activity Summary: Satellite data show that the recent explosion of Cleveland volcano at 05:49 UTC (21:49 local time) produced a small ash cloud up to 22,000 ft asl moving southeast. No other significant activity has been detected.

Explosions from Cleveland typically produce relatively small volcanic ash clouds that dissipate within hours; however, more significant ash emissions are possible.

Cleveland volcano is monitored with a limited real-time seismic network, which inhibits AVO's ability to detect precursory unrest that may lead to an explosive eruption. Rapid detection of an ash-producing eruption may be possible using a combination of seismic, infrasound, lightning, and satellite data.
(12) Volcanic cloud height: 22,000 ft asl
(13) Other volcanic cloud information: Ash seen in satellite imagery. Cloud drifting southeast
(14) Remarks:
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jessica Larsen, Acting Coordinating Scientist, UAF
jflarsen@alaska.edu (907) 322-4085
(16) Next Notice:
2018-05-05 - Cleveland, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20180505/0620Z)
(3) Volcano: Cleveland (VNUM #311240)
(4) Current Color Code: ORANGE
(5) Previous Color Code: YELLOW
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 52 deg 49 min W 169 deg 56 min
(9) Area: Aleutians
(10) Summit Elevation: 5676 ft (1730 m)
(11) Volcanic Activity Summary: Local seismic and infrasound sensors recorded a small explosion tonight at 05:49 UTC (21:49 local time). A few small earthquakes were also recorded at the volcano during the previous several days. No other significant activity was detected. No volcanic cloud has been detected in satellite imagery.

Explosions from Cleveland typically produce relatively small volcanic ash clouds that dissipate within hours; however, more significant ash emissions are possible.

Cleveland volcano is monitored with a limited real-time seismic network, which inhibits AVO's ability to detect precursory unrest that may lead to an explosive eruption. Rapid detection of an ash-producing eruption may be possible using a combination of seismic, infrasound, lightning, and satellite data.
(12) Volcanic cloud height: None
(13) Other volcanic cloud information: n/a
(14) Remarks:
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jessica Larsen, Acting Coordinating Scientist, UAF
jflarsen@alaska.edu (907) 322-4085
(16) Next Notice:
2018-04-06 - Cleveland, Aviation Color Code: YELLOW (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20180406/1831Z)
(3) Volcano: Cleveland (VNUM #311240)
(4) Current Color Code: YELLOW
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 52 deg 49 min W 169 deg 56 min
(9) Area: Aleutians
(10) Summit Elevation: 5676 ft (1730 m)
(11) Volcanic Activity Summary: The last detected explosive activity at Cleveland volcano occurred April 4, 2018. We have no evidence of significant eruptive activity since that time. Thus, AVO is lowering the Aviation Color Code to YELLOW and the Volcano Alert Level to ADVISORY.

Future explosive activity is likely, and would likely occur without warning. Explosions from Cleveland typically produce relatively small volcanic ash clouds that dissipate within hours; however, more significant ash emissions are possible.

Cleveland volcano is monitored by only two seismic stations, which restricts AVO's ability to detect precursory unrest that may lead to an explosive eruption. Rapid detection of an ash-producing eruption may be possible using a combination of seismic, infrasound, lightning, and satellite data.
(12) Volcanic cloud height: None
(13) Other volcanic cloud information: n/a
(14) Remarks:
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS, mcoombs@usgs.gov (907) 786-7497

David Fee, Acting Coordinating Scientist, UAFGI
dfee1@alaska.edu (907) 322-4085
(16) Next Notice:
2018-04-04 - Cleveland, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20180404/1235Z)
(3) Volcano: Cleveland (VNUM #311240)
(4) Current Color Code: ORANGE
(5) Previous Color Code: YELLOW
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 52 deg 49 min W 169 deg 56 min
(9) Area: Aleutians
(10) Summit Elevation: 5676 ft (1730 m)
(11) Volcanic Activity Summary: Local seismic and infrasound sensors recorded a small explosion today at 11:55 UTC (03:55 AKST). We are raising the Aviation Color Code to ORANGE and the Alert Level to WATCH.

Explosions from Cleveland typically produce relatively small volcanic ash clouds that dissipate within hours. No ash cloud from this event has been seen in satellite images, which currently are partly obscured by weather clouds.

Cleveland volcano is monitored with a limited real-time seismic network, which inhibits AVO's ability to detect precursory unrest that may lead to an explosive eruption. Rapid detection of an ash-producing eruption may be possible using a combination of seismic, infrasound, lightning, and satellite data.
(12) Volcanic cloud height: None
(13) Other volcanic cloud information: n/a
(14) Remarks:
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS, mcoombs@usgs.gov (907) 786-7497

Jeff Freymueller, Coordinating Scientist, UAFGI, jfreymueller@alaska.edu (907) 322-4085
(16) Next Notice:
2018-04-04 - Cleveland, Aviation Color Code: YELLOW (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20180404/1223Z)
(3) Volcano: Cleveland (VNUM #311240)
(4) Current Color Code: YELLOW
(5) Previous Color Code: YELLOW
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 52 deg 49 min W 169 deg 56 min
(9) Area: Aleutians
(10) Summit Elevation: 5676 ft (1730 m)
(11) Volcanic Activity Summary: Local seismic and infrasound sensors recorded a small explosion today at 11:55 UTC (03:55 AKST). A few small earthquakes were also recorded at the volcano during the last 24 hours. No other significant activity was detected.

Explosions from Cleveland typically produce relatively small volcanic ash clouds that dissipate within hours; however, more significant ash emissions are possible.

Cleveland volcano is monitored with a limited real-time seismic network, which inhibits AVO's ability to detect precursory unrest that may lead to an explosive eruption. Rapid detection of an ash-producing eruption may be possible using a combination of seismic, infrasound, lightning, and satellite data.
(12) Volcanic cloud height: None
(13) Other volcanic cloud information: n/a
(14) Remarks:
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS, mcoombs@usgs.gov (907) 786-7497

Jeff Freymueller, Coordinating Scientist, UAFGI, jfreymueller@alaska.edu (907) 322-4085
(16) Next Notice:
2018-03-06 - Cleveland, Aviation Color Code: YELLOW (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20180306/2133Z)
(3) Volcano: Cleveland (VNUM #311240)
(4) Current Color Code: YELLOW
(5) Previous Color Code: GREEN
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 52 deg 49 min W 169 deg 56 min
(9) Area: Aleutians
(10) Summit Elevation: 5676 ft (1730 m)
(11) Volcanic Activity Summary: Cleveland Volcano remains at Aviation Color Code YELLOW and Alert Level ADVISORY. The Volcanic Activity Notice sent out at 12:06 AKST today was in error. There have been no changes in activity at the volcano.
(12) Volcanic cloud height: None
(13) Other volcanic cloud information: n/a
(14) Remarks:
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Pavel Izbekov, Acting Coordinating Scientist, UAFGI
peizbekov@alaska.edu (907) 322-4085
(16) Next Notice:
2018-03-06 - Cleveland, Aviation Color Code: GREEN (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20180306/2106Z)
(3) Volcano: Cleveland (VNUM #311240)
(4) Current Color Code: GREEN
(5) Previous Color Code: YELLOW
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2018/A94
(8) Volcano Location: N 52 deg 49 min W 169 deg 56 min
(9) Area: Aleutians
(10) Summit Elevation: 5676 ft (1730 m)
(11) Volcanic Activity Summary: TEST The last detected explosive activity at Cleveland Volcano occurred March 2, 2018. There is no evidence of significant eruptive activity since that time, and a clear satellite view today showed no new lava effusion in the crater. Thus, AVO is lowering the Aviation Color Code to YELLOW and the Volcano Alert Level to ADVISORY.

Future explosive activity is likely, and would likely occur without warning. Explosions from Cleveland typically produce relatively small volcanic ash clouds that dissipate within hours; however, more significant ash emissions are possible.

Cleveland volcano is monitored with a limited real-time seismic network, which inhibits AVO's ability to detect precursory unrest that may lead to an explosive eruption. Rapid detection of an ash-producing eruption may be possible using a combination of seismic, infrasound, lightning, and satellite data.
(12) Volcanic cloud height: None
(13) Other volcanic cloud information: n/a
(14) Remarks:
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Pavel Izbekov, Acting Coordinating Scientist, UAFGI
peizbekov@alaska.edu (907) 322-4085
(16) Next Notice:
2018-03-05 - Cleveland, Aviation Color Code: YELLOW (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20180305/2214Z)
(3) Volcano: Cleveland (VNUM #311240)
(4) Current Color Code: YELLOW
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 52 deg 49 min W 169 deg 56 min
(9) Area: Aleutians
(10) Summit Elevation: 5676 ft (1730 m)
(11) Volcanic Activity Summary: The last detected explosive activity at Cleveland Volcano occurred March 2, 2018. There is no evidence of significant eruptive activity since that time, and a clear satellite view today showed no new lava effusion in the crater. Thus, AVO is lowering the Aviation Color Code to YELLOW and the Volcano Alert Level to ADVISORY.

Future explosive activity is likely, and would likely occur without warning. Explosions from Cleveland typically produce relatively small volcanic ash clouds that dissipate within hours; however, more significant ash emissions are possible.

Cleveland volcano is monitored with a limited real-time seismic network, which inhibits AVO's ability to detect precursory unrest that may lead to an explosive eruption. Rapid detection of an ash-producing eruption may be possible using a combination of seismic, infrasound, lightning, and satellite data.
(12) Volcanic cloud height: None
(13) Other volcanic cloud information: n/a
(14) Remarks:
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Pavel Izbekov, Acting Coordinating Scientist, UAFGI
peizbekov@alaska.edu (907) 322-4085
(16) Next Notice:
2018-03-02 - Cleveland, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20180302/1538Z)
(3) Volcano: Cleveland (VNUM #311240)
(4) Current Color Code: ORANGE
(5) Previous Color Code: YELLOW
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 52 deg 49 min W 169 deg 56 min
(9) Area: Aleutians
(10) Summit Elevation: 5676 ft (1730 m)
(11) Volcanic Activity Summary: Local seismic and infrasound sensors recorded a small explosion today at 14:57 UTC (05:57 AKST). No other significant activity was detected. A volcanic cloud was observed heading ENE at an altitude of about 15,000 ft.

Explosions from Cleveland typically produce relatively small volcanic ash clouds that dissipate within hours; however, more significant ash emissions are possible.

Cleveland volcano is monitored with a limited real-time seismic network, which inhibits AVO's ability to detect precursory unrest that may lead to an explosive eruption. Rapid detection of an ash-producing eruption may be possible using a combination of seismic, infrasound, lightning, and satellite data.
(12) Volcanic cloud height: None
(13) Other volcanic cloud information: n/a
(14) Remarks:
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jeff Freymueller, Coordinating Scientist, UAFGI
jfreymueller@alaska.edu (907) 322-4085
(16) Next Notice:
2018-02-09 - Cleveland, Aviation Color Code: YELLOW (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20180209/2244Z)
(3) Volcano: Cleveland (VNUM #311240)
(4) Current Color Code: YELLOW
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2018/A92
(8) Volcano Location: N 52 deg 49 min W 169 deg 56 min
(9) Area: Aleutians
(10) Summit Elevation: 5676 ft (1730 m)
(11) Volcanic Activity Summary: The last detected explosive activity at Cleveland Volcano was on December 18, 2017. There is no evidence of significant activity since that time. Thus, AVO is reducing the Aviation Color Code to YELLOW and the Volcano Alert Level to ADVISORY. Future explosive activity is likely, and would occur without warning. Previous explosions have produced hazardous conditions primarily near the summit crater, but occasionally they have been large enough to produce a drifting ash cloud.

Cleveland Volcano is not monitored with a full real-time seismic network and this inhibits AVO's ability to detect unrest that may lead to future activity. We are able to detect explosive activity using infrasound and limited seismic instruments on the island.
(12) Volcanic cloud height: None
(13) Other volcanic cloud information: n/a
(14) Remarks:
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Pavel Izbekov, Acting Coordinating Scientist, UAFGI
peizbekov@alaska.edu (907) 322-4085
(16) Next Notice:
2018-02-07 - Shishaldin, Aviation Color Code: GREEN (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20180207/2301Z)
(3) Volcano: Shishaldin (VNUM #311360)
(4) Current Color Code: GREEN
(5) Previous Color Code: YELLOW
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2018/A88
(8) Volcano Location: N 54 deg 45 min W 163 deg 58 min
(9) Area: Aleutians
(10) Summit Elevation: 9373 ft (2857 m)
(11) Volcanic Activity Summary: The Alaska Volcano Observatory is decreasing the Aviation Color Code to GREEN and the Alert Level to NORMAL at Shishaldin Volcano based on declining seismic and infrasound activity over the past month. These observations represent a return to normal background activity at Shishaldin.

Shishaldin is monitored by local seismic and infrasound sensors, satellite data, a web camera, a telemetered geodetic network, and distant infrasound networks.
(12) Volcanic cloud height: None
(13) Other volcanic cloud information: N/A
(14) Remarks: Shishaldin volcano, located near the center of Unimak Island in the eastern Aleutian Islands, is a spectacular symmetric cone with a base diameter of approximately 16 km (10 mi). A 200-m-wide (660 ft) funnel-shaped summit crater typically emits a steam plume and occasional small amounts of ash. Shishaldin is one of the most active volcanoes in the Aleutian volcanic arc, with at least 54 episodes of unrest including over 24 confirmed eruptions since 1775. Most eruptions are relatively small, although the April-May 1999 event generated an ash column that reached 45,000 ft above sea level.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Pavel Izbekov, Acting Coordinating Scientist, UAFGI
pavel@gi.alaska.edu (907) 322-4085
(16) Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at
http://www.avo.alaska.edu
2018-01-18 - Great Sitkin, Aviation Color Code: GREEN (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20180118/2236Z)
(3) Volcano: Great Sitkin (VNUM #311120)
(4) Current Color Code: GREEN
(5) Previous Color Code: YELLOW
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2018/A55
(8) Volcano Location: N 52 deg 4 min W 176 deg 6 min
(9) Area: Aleutians
(10) Summit Elevation: 5709 ft (1740 m)
(11) Volcanic Activity Summary: Earthquake activity at Great Sitkin Volcano has declined over the past two months to near background levels. No significant activity has been observed in satellite data during this time period and no steam plumes have been reported. AVO is thus lowering the Aviation Color Code and Alert Level to GREEN/NORMAL.

The number of earthquakes located at Great Sitkin increased as early as late July 2016, and the elevated seismicity continued throughout most of 2017. The unrest was likely the result of a magma intrusion beneath the volcano. The decline over the past two months in the number of earthquakes suggests the intrusion has stalled and the volcano is returning to a period of background seismicity. Future intrusions at Great Sitkin should also lead to an increase in earthquakes prior to any eruptive activity.

Great Sitkin Volcano is monitored by a five-station seismic network on Great Sitkin Island and with additional seismic stations on the nearby islands of Igitkin, Adak, Kagalaska, and Kanaga. A six-element infrasound array to detect explosions (atmospheric pressure waves) was installed on Adak Island in June, 2017. AVO also uses satellite imagery to monitor Great Sitkin Volcano.
(12) Volcanic cloud height: not applicable
(13) Other volcanic cloud information: Unknown
(14) Remarks: Great Sitkin Volcano is a basaltic andesite volcano that occupies most of the northern half of Great Sitkin Island, a member of the Andreanof Islands group in the central Aleutian Islands. It is located 43 km (26 miles) east of the community of Adak. The volcano is a composite structure consisting of an older dissected volcano and a younger parasitic cone with a 3-km-diameter summit crater. A steep-sided lava dome, emplaced during an eruption in 1974, occupies the center of the crater. Great Sitkin erupted at least three times in the 20th century, most recently in 1974. That eruption produced at least one ash cloud that likely exceeded an altitude of 25,000 ft above sea level. A poorly documented eruption occurred in 1945, also producing a lava dome that was partially destroyed in the 1974 eruption. Within the past 280 years a large explosive eruption produced pyroclastic flows that partially filled the Glacier Creek valley on the southwest flank.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jeff Freymueller, Coordinating Scientist, UAFGI
jfreymueller@alaska.edu (907) 322-4085
(16) Next Notice:
2017-12-16 - Anatahan, Aviation Color Code: UNASSIGNED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20171216/0049Z)
(3) Volcano: Anatahan (VNUM #284200)
(4) Current Color Code: UNASSIGNED
(5) Previous Color Code:
(6) Source: U.S. Geological Survey
(7) Notice Number: 2017/N38
(8) Volcano Location: N 16 deg 21 min E 145 deg 40 min
(9) Area: Northern Mariana Islands
(10) Summit Elevation: 2592 ft (790 m)
(11) Volcanic Activity Summary: The USGS is moving the status of Anatahan volcano from Aviation Color Code GREEN to “unassigned”. The USGS is no longer receiving data streams from monitoring instruments on Anatahan or Sarigan. Due to this lack of monitoring data, the USGS can no longer detect precursory activity that may be leading to an eruption at Anatahan nor quickly confirm or dismiss reports of activity at the volcano. Thus the USGS cannot say with any certainty that the volcano is at normal or background levels of activity. A storm moving through the area in August of 2017 damaged a repeater site that telemetered data from these seismic, camera, and infrasound networks to the CNMI Homeland Security and Emergency Management (HSEM) offices in Saipan. Repeated attempts to remotely repair the radio equipment have failed and the lack of helicopter support in the area makes it impossible to visit the site to affect repairs. The detection of a large eruption at Anatahan is possible using a combination of data from a seismic and infrasound network on Saipan, monitoring for signs of volcanic lightning, and analysis of satellite data, however no forewarning of such an event is currently possible.
(12) Volcanic cloud height: Not applicable
(13) Other volcanic cloud information: Not applicable
(14) Remarks:
(15) Contacts: CONTACT INFORMATION:
CNMI Homeland Security and Emergency Management
cnmihsem.gov.mp

USGS Northern Mariana Duty Scientist (808) 967-8815
volcano.wr.usgs.gov/cnmistatus.php

Satellite information, Washington VAAC
www.ssd.noaa.gov/VAAC/washington.html
(16) Next Notice:
2017-12-13 - Cleveland, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20171213/1515Z)
(3) Volcano: Cleveland (VNUM #311240)
(4) Current Color Code: ORANGE
(5) Previous Color Code: YELLOW
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 52 deg 49 min W 169 deg 56 min
(9) Area: Aleutians
(10) Summit Elevation: 5676 ft (1730 m)
(11) Volcanic Activity Summary: An explosion was detected at Cleveland Volcano in seismic and infrasound data this morning 04:20 AKST (13:20 UTC). The explosion produced an eruption cloud that was observed in satellite data to an altitude of up to 20,000 ft asl and moving to the east. AVO is raising the color code for Cleveland to Aviation Color Code ORANGE and Alert Level WATCH.
(12) Volcanic cloud height: Small cloud detected. NWS eruption SIGMET issued to 20,000 ft asl.
(13) Other volcanic cloud information: Cloud moving to the east.
(14) Remarks: The National Weather Service Alaska Aviation Weather Unit has issued an eruption SIGMET warning for aviation up to 20,000 ft above sea level. This may be revised as new information becomes available. Please see the NWS AAWU at http://www.weather.gov/aawu/sigmets for updated information on aviation warning messages.

Cleveland volcano is not monitored with a full real-time seismic network and this inhibits AVO's ability to detect unrest that may lead to future activity. We are able to detect explosive activity using infrasound and limited seismic instruments on the island.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jessica Larsen, Acting Coordinating Scientist, UAF
jflarsen@alaska.edu (907) 322-4085
(16) Next Notice:
2017-12-12 - Cleveland, Aviation Color Code: YELLOW (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20171212/2131Z)
(3) Volcano: Cleveland (VNUM #311240)
(4) Current Color Code: YELLOW
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 52 deg 49 min W 169 deg 56 min
(9) Area: Aleutians
(10) Summit Elevation: 5676 ft (1730 m)
(11) Volcanic Activity Summary: Recent satellite images of Cleveland Volcano show that lava effusion in the summit has likely ceased. Activity at Cleveland over the past several weeks has been characterized by small to very small explosions that have reduced the dome in the crater to rubble but have not produce detectable eruption clouds. Due to the low level of current activity, AVO is lowering the Aviation Color Code to YELLOW and the Volcano Alert Level to ADVISORY.
(12) Volcanic cloud height: Not applicable
(13) Other volcanic cloud information: Not applicable
(14) Remarks: Cleveland volcano is not monitored with a full real-time seismic network and this inhibits AVO's ability to detect unrest that may lead to future activity. We are able to detect explosive activity using infrasound and limited seismic instruments on the island.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jessica Larsen, Acting Coordinating Scientist, UAF
jflarsen@alaska.edu (907) 322-4085
(16) Next Notice:
2017-12-06 - Bogoslof, Aviation Color Code: UNASSIGNED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20171206/2009Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: UNASSIGNED
(5) Previous Color Code: YELLOW
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: The last detected explosive activity at Bogoslof occurred on August 30, 2017. Over the past three months there has been no significant activity observed in seismic, infrasound, satellite or lightning data. Thus, we are decreasing the Aviation Color Code and Alert Level to UNASSIGNED.

AVO only assigns Aviation Color Codes and Alert Levels to volcanoes that have a local seismic monitoring network. Activity at Bogoslof has been detected using instruments from distant sites, thus we can not say authoritatively that the volcano has returned to its normal background state. However, we are no longer detecting any activity that would be considered to be indicative of unrest.

A resumption of eruptive activity is possible. It is likely that we would be able to detect significant explosive activity if it where to occur.
(12) Volcanic cloud height: None
(13) Other volcanic cloud information: N/A
(14) Remarks:
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jeff Freymueller, Coordinating Scientist, UAFGI
jfreymueller@alaska.edu (907) 322-4085
(16) Next Notice:
2017-12-06 - Shishaldin, Aviation Color Code: YELLOW (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20171206/2006Z)
(3) Volcano: Shishaldin (VNUM #311360)
(4) Current Color Code: YELLOW
(5) Previous Color Code: GREEN
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 54 deg 45 min W 163 deg 58 min
(9) Area: Aleutians
(10) Summit Elevation: 9373 ft (2857 m)
(11) Volcanic Activity Summary: The Alaska Volcano Observatory is raising the Aviation Color Code to YELLOW and the Alert Level to ADVISORY at Shishaldin Volcano based on increased seismic and infrasound activity over the past few weeks. These observations represent a departure from normal background activity at Shishaldin, but do not necessarily indicate that an eruption will occur.

Shishaldin is monitored by local seismic and infrasound sensors, satellite data, a web camera, a telemetered geodetic network, and distant infrasound networks.
(12) Volcanic cloud height: None
(13) Other volcanic cloud information: N/A
(14) Remarks: Shishaldin volcano, located near the center of Unimak Island in the eastern Aleutian Islands, is a spectacular symmetric cone with a base diameter of approximately 16 km (10 mi). A 200-m-wide (660 ft) funnel-shaped summit crater typically emits a steam plume and occasional small amounts of ash. Shishaldin is one of the most active volcanoes in the Aleutian volcanic arc, with at least 54 episodes of unrest including over 24 confirmed eruptions since 1775. Most eruptions are relatively small, although the April-May 1999 event generated an ash column that reached 45,000 ft above sea level.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jeff Freymueller, Coordinating Scientist, UAFGI
jfreymueller@alaska.edu (907) 322-4085
(16) Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at
http://www.avo.alaska.edu
2017-11-22 - Great Sitkin, Aviation Color Code: YELLOW (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20171122/1957Z)
(3) Volcano: Great Sitkin (VNUM #311120)
(4) Current Color Code: YELLOW
(5) Previous Color Code:
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 52 deg 4 min W 176 deg 6 min
(9) Area: Aleutians
(10) Summit Elevation: 5709 ft (1740 m)
(11) Volcanic Activity Summary: Recent observations of a robust steam plume and a period of gradually increasing seismicity over several months indicate that Great Sitkin Volcano has become restless and is exhibiting behavior that is above background levels. AVO is thus raising the aviation color code and volcano alert level to YELLOW/ADVISORY.

Photographs of the volcano taken by local observers on Sunday, November 19 show a light-colored vapor plume rising about 300 m (1,000 ft) above the vent area and extending about 15-20 km (9 –12 mi) to the south. Nothing unusual was observed in seismic or infrasound data around the time the photographs were taken and nothing noteworthy has been observed in satellite data since the emissions were observed.

An increased number of small earthquakes was evident as early as late July 2016, and since then the level of seismic activity has fluctuated at low levels but has exhibited a gradual overall increase most notable since June 2017. Seismic activity to date has been characterized by earthquakes that are typically less than magnitude 1.0 and range in depth from near the summit of the volcano to 30 km below sea level. Most earthquakes are in one of two clusters, beneath the volcano's summit or just offshore the northwest coast of the island. The largest earthquake so far was a magnitude 2.8 on September 29, 2017.

Possible explosion signals were observed in seismic data on January 10 and July 21 of this year, but no confirmed emissions were observed locally or detected in infrasound data or satellite imagery. Great Sitkin has experienced at least one other episode of unrest characterized by vigorous steaming. This last occurred in 1953 but no subsequent eruptive activity developed. Minor steaming in the vicinity of the 1974 lava dome was observed in 1986 and in 2012 but no associated eruptive activity occurred.

Great Sitkin Volcano is monitored by a five-station seismic network on Great Sitkin Island and with additional seismic stations on the nearby islands of Igitkin, Adak, Kagalaska, and Kanaga. A six-element infrasound array to detect explosions (atmospheric pressure waves), was installed on Adak Island in June, 2017. AVO also uses satellite imagery to monitor Great Sitkin Volcano.

The current unrest is likely the result of magma intrusion beneath the volcano. Typically, such intrusions release gas, which can increase stress in the crust and lead to an increase in the number of earthquakes. If gases build up near the surface, they may be released suddenly in small explosions or robust emissions. It is possible, but not certain, that the volcano may eventually erupt. Prior to a significant eruptive event an even greater increase in seismicity should occur as magma rises to shallower levels in the crust. An ash-producing eruption similar to the most recent historical eruption in 1974 could generate airborne ash that may pose hazards to aircraft. Ash fallout on the nearby community of Adak and the surrounding ocean may also occur.
(12) Volcanic cloud height: not applicable
(13) Other volcanic cloud information: Unknown
(14) Remarks: Great Sitkin Volcano is a basaltic andesite volcano that occupies most of the northern half of Great Sitkin Island, a member of the Andreanof Islands group in the central Aleutian Islands. It is located 43 km (26 miles) east of the community of Adak. The volcano is a composite structure consisting of an older dissected volcano and a younger parasitic cone with a 3-km-diameter summit crater. A steep-sided lava dome, emplaced during an eruption in 1974, occupies the center of the crater. Great Sitkin erupted at least three times in the 20th century, most recently in 1974. That eruption produced at least one ash cloud that likely exceeded an altitude of 25,000 ft above sea level. A poorly documented eruption occurred in 1945, also producing a lava dome that was partially destroyed in the 1974 eruption. Within the past 280 years a large explosive eruption produced pyroclastic flows that partially filled the Glacier Creek valley on the southwest flank.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jeff Freymueller, Coordinating Scientist, UAFGI
jfreymueller@alaska.edu (907) 322-4085
(16) Next Notice:
2017-09-26 - Cleveland, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170926/0215Z)
(3) Volcano: Cleveland (VNUM #311240)
(4) Current Color Code: ORANGE
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 52 deg 49 min W 169 deg 56 min
(9) Area: Aleutians
(10) Summit Elevation: 5676 ft (1730 m)
(11) Volcanic Activity Summary: A moderate, 2-minute-long eruption occurred at Cleveland Volcano beginning at 17:47 September 25 AKDT (01:47 September 26 UTC). The explosion was detected by seismic and infrasound (air pressure) sensors. Nothing has been observed in satellite data so far. We are keeping the Aviation Color Code/Alert Level at ORANGE/WATCH.
(12) Volcanic cloud height: Unknown
(13) Other volcanic cloud information: Unknown
(14) Remarks: Cleveland volcano is not monitored with a full real-time seismic network and this inhibits AVO's ability to detect unrest that may lead to future activity. We are able to detect explosive activity using infrasound and limited seismic instruments on the island.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jeff Freymueller, Coordinating Scientist, UAFGI
jfreymueller@alaska.edu (907) 322-4085
(16) Next Notice:
2017-08-30 - Pavlof, Aviation Color Code: GREEN (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170830/1931Z)
(3) Volcano: Pavlof (VNUM #312030)
(4) Current Color Code: GREEN
(5) Previous Color Code: YELLOW
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 55 deg 25 min W 161 deg 53 min
(9) Area: Alaska Peninsula
(10) Summit Elevation: 8261 ft (2518 m)
(11) Volcanic Activity Summary: Since mid June, 2017, unrest at Pavlof Volcano has gradually declined to levels now considered as normal background, non-eruptive behavior. The March 2016 eruption changed the configuration of the summit crater, such that it is slightly wider and has a more vertical orientation than before the 2016 eruption. Since then, the volcano has remained relatively quiet, although there was a brief period of elevated seismicity in early June, 2017 that resulted in AVO raising the Aviation Color Code to Yellow and the Alert Level to Advisory where it has remained until today.

Many satellite views of the summit are now able to detect elevated surface temperatures within the crater and upper part of the volcanic conduit most likely associated with the emission of hot gases. This is now considered the normal thermal state of the volcano. Occasional emission of vapor plumes from the summit crater, sometimes visible from Cold Bay and Sand Point, is now relatively common. These emissions are also considered normal background behavior for Pavlof Volcano. On the basis of these observations, and the lack of any noteworthy seismic activity for the past several months, we are lowering the Aviation Color Code to Green and the Alert Level to Normal.
(12) Volcanic cloud height: Unknown
(13) Other volcanic cloud information: Unknown
(14) Remarks: Pavlof Volcano is a snow- and ice-covered stratovolcano located on the southwestern end of the Alaska Peninsula about 953 km (592 mi) southwest of Anchorage. The volcano is about 7 km (4.4 mi) in diameter and has active vents on the north and east sides close to the summit. With over 40 historic eruptions, it is one of the most consistently active volcanoes in the Aleutian arc. Eruptive activity is generally characterized by sporadic Strombolian lava fountaining continuing for a several-month period. Ash plumes as high as 49,000 ft ASL have been generated by past eruptions of Pavlof, and during the March 2016 eruption, ash plumes as high as 40,000 feet above sea level were generated and the ash was tracked in satellite data as distant as eastern Canada. The nearest community, Cold Bay, is located 60 km (37 miles) to the southwest of Pavlof.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jeff Freymueller, Coordinating Scientist, UAFGI
jfreymueller@alaska.edu (907) 322-4085
(16) Next Notice:
2017-08-30 - Bogoslof, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170830/1315Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: ORANGE
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: AVO has detected an increase in seismic activity and infrasound consistent with an explosive eruption at Bogoslof volcano beginning at 12:05 UTC (04:05 AKDT) August 30 and continuing. A low-level ash cloud producing lightning has been detected in satellite data, but does not appear to be much higher than about 20,000 feet above sea level. Emission of volcanic ash is likely occurring based on seismic, infrasound, lightning, and satellite data. Winds are toward south-southeast.

The Aviation Color Code remains at ORANGE and the Volcano Alert Level remains at WATCH. AVO is evaluating all data sources and will provide more information as it becomes available.
(12) Volcanic cloud height: About 20,000 feet above sea level
(13) Other volcanic cloud information: winds toward south southeast
(14) Remarks: Please see the NWS AAWU at http://www.weather.gov/aawu/sigmets for updated information on aviation warning messages.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jeff Freymueller, Coordinating Scientist, UAFGI
jfreymueller@alaska.edu (907) 322-4085
(16) Next Notice:
2017-08-28 - Bogoslof, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170828/1939Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: ORANGE
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: AVO has detected an explosive eruption at Bogoslof volcano beginning at 19:17 UTC (11:17 AKDT) August 28 and lasting about 2 minutes. No ash cloud has yet been detected in satellite data, but volcanic ash emission has likely occurred based on seismic and infrasound data. Winds are toward southeast.

The Aviation Color Code remains at ORANGE and the Volcano Alert Level remains at WATCH. AVO is evaluating all data sources and will provide more information as it becomes available.
(12) Volcanic cloud height: None detected yet.
(13) Other volcanic cloud information: winds toward southeast
(14) Remarks: Please see the NWS AAWU at http://www.weather.gov/aawu/sigmets for updated information on aviation warning messages.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jeff Freymueller, Coordinating Scientist, UAFGI
jfreymueller@alaska.edu (907) 322-4085
(16) Next Notice:
2017-08-28 - Bogoslof, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170828/1153Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: ORANGE
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: An explosive eruption began at Bogoslof volcano at 11:23 UTC (03:23 AKDT) on August 28 and is ongoing. No ash cloud has been detected as of yet in satellite data, but volcanic ash emission likely occurred based on seismic and infrasound data. Signal strengths suggest that the cloud is likely above 20,000 ft asl. Winds are towards the east-southeast.

The Aviation Color Code remains at ORANGE and the Volcano Alert Level remains at WATCH. AVO is evaluating all data sources and will provide more information as it becomes available.
(12) Volcanic cloud height: None detected yet.
(13) Other volcanic cloud information: winds toward east-southeast
(14) Remarks: Please see the NWS AAWU at http://www.weather.gov/aawu/sigmets for updated information on aviation warning messages.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jeff Freymueller, Coordinating Scientist, UAFGI
jfreymueller@alaska.edu (907) 322-4085
(16) Next Notice:
2017-08-27 - Bogoslof, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170827/2340Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: ORANGE
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: A brief explosive eruption began at Bogoslof volcano at 23:08 UTC (15:08 AKDT) on August 27 and lasted about two minutes. No ash cloud has been detected as of yet in satellite data, but volcanic ash emission likely occurred based on seismic and infrasound data. Signal strengths suggest that the cloud is likely below 20,000 ft asl. Winds are towards the southeast.

The Aviation Color Code remains at ORANGE and the Volcano Alert Level remains at WATCH. AVO is evaluating all data sources and will provide more information as it becomes available.
(12) Volcanic cloud height: None detected yet.
(13) Other volcanic cloud information: winds toward southeast
(14) Remarks: Please see the NWS AAWU at http://www.weather.gov/aawu/sigmets for updated information on aviation warning messages.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jeff Freymueller, Coordinating Scientist, UAFGI
jfreymueller@alaska.edu (907) 322-4085
(16) Next Notice:
2017-08-27 - Bogoslof, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170827/0102Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: ORANGE
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: A short-lived eruption began at Bogoslof volcano at 00:29 UTC on August 27 (16:29 AKDT on August 26) and lasted about 4 minutes. No ash cloud has been detected as of yet in satellite data, but volcanic ash emissions likely occurred based on seismic and infrasound data.

We are evaluating the magnitude of this eruptive episode. The Aviation Color Code remains at ORANGE and the Volcano Alert Level remains at WATCH at present.
(12) Volcanic cloud height: None detected yet
(13) Other volcanic cloud information: Winds toward southeast
(14) Remarks: Please see the NWS AAWU at http://www.weather.gov/aawu/sigmets for updated information on aviation warning messages.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jeff Freymueller, Coordinating Scientist, UAFGI
jfreymueller@alaska.edu (907) 322-4085
(16) Next Notice:
2017-08-22 - Cleveland, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170822/1918Z)
(3) Volcano: Cleveland (VNUM #311240)
(4) Current Color Code: ORANGE
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 52 deg 49 min W 169 deg 56 min
(9) Area: Aleutians
(10) Summit Elevation: 5676 ft (1730 m)
(11) Volcanic Activity Summary: A moderate, 1-minute-long eruption occurred at Cleveland Volcano beginning at 10:43 AKDT (18:43 UTC) on 22 August. The explosion was detected by seismic and infrasound (air pressure) sensors. Nothing has been observed in satellite data so far. We are keeping the Aviation Color Code/Alert Level at ORANGE/WATCH.
(12) Volcanic cloud height: N/A
(13) Other volcanic cloud information: N/A
(14) Remarks: Cleveland volcano is not monitored with a full real-time seismic network and this inhibits AVO's ability to detect unrest that may lead to future activity. We are able to detect explosive activity using infrasound and limited seismic instruments on the island.
(15) Contacts: John Paskievitch, Acting Scientist-in-Charge, USGS
jpaskie@usgs.gov (907) 786-7497

Jeff Freymueller, Coordinating Scientist, UAFGI jfreymueller@alaska.edu (907) 322-4085
(16) Next Notice:
2017-08-08 - Bogoslof, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170808/1819Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: ORANGE
(5) Previous Color Code: RED
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: No further ash emissions have occurred at Bogoslof Volcano since the three-hour-long eruption on Monday, 7 August that began around 10:00 AKST (18:00 UTC), and seismicity remains low. We are therefore lowering the Aviation Color Code to ORANGE and the Alert Level to WATCH. Additional ash-producing eruptions could occur at any time, however, with no detectable precursors.
(12) Volcanic cloud height: Not applicable
(13) Other volcanic cloud information: Not applicable
(14) Remarks:
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

David Fee, Acting Coordinating Scientist, UAFGI
dfee1@alaska.edu (907) 322-4085
(16) Next Notice:
2017-08-07 - Bogoslof, Aviation Color Code: RED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170807/1853Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: RED
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: A significant explosive eruption began at Bogoslof volcano at about 18:00 UTC (10:00 AKDT) on August 7 and is continuing. A pilot report at 18:45 UTC indicates that the ash cloud had reached 32,000 ft asl. Thus, AVO is raising the Aviation Color Code to RED and Alert level to WARNING for Bogoslof volcano.

Winds are currently to the south. Seismic and infrasound data suggest that the ash emissions are continuing.
(12) Volcanic cloud height: 32,000 ft asl estimated by pilot report
(13) Other volcanic cloud information: Cloud moving towards south
(14) Remarks: The SIGMET warning message for aviation, issued by the National Weather Service Alaska Aviation Weather Unit, currently is in effect up to 32,000 ft above sea level. Status of the ash cloud forecast can be found at their website at http://aawu.arh.noaa.gov/

See http://www.weather.gov/afc/ for details about expected ash fallout.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

David Fee, Acting Coordinating Scientist, UAFGI
dfee1@alaska.edu (907) 322-4085
(16) Next Notice:
2017-08-07 - Bogoslof, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170807/1834Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: ORANGE
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: An explosive eruption of Bogoslof volcano began at about 18:00 UTC (10:00 AKDT) based on infrasound and seismic activity following more than an hour of increased seismicity. Satellite data from 18:00 UTC show an eruption cloud rising above the low cloud deck which is at an altitude of about 1500 ft. asl. There is no estimate of the eruption cloud height as of this time. As of yet there is no lightning activity that it typically observed during significant ash emissions. This suggests that the activity is currently at a low level and the Aviation Color Code remains at ORANGE and the Volcano Alert Level remains at WATCH.

AVO is evaluating all data sources and will update this report as more information becomes available.
(12) Volcanic cloud height: Not determined yet
(13) Other volcanic cloud information: Visible in satellite data from 18:00 UTC
(14) Remarks: Status of any ash clouds can be found at the Alaska Aviation Weather Unit website at http://aawu.arh.noaa.gov/
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

David Fee, Acting Coordinating Scientist, UAFGI
dfee1@alaska.edu (907) 322-4085
(16) Next Notice:
2017-07-11 - Bogoslof, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170711/0158Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: ORANGE
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: An eruption of Bogoslof volcano began at 1:06 UTC on July 11 (17:06 AKDT on July 10) and lasted about 15 minutes based on seismic data. No volcanic cloud has been observed in satellite data, and no volcanic lightning or infrasound has been detected. Winds are toward the east-southeast.

We are evaluating the magnitude of this eruptive episode. The Aviation Color Code remains at ORANGE and the Volcano Alert Level remains at WATCH at present. AVO is evaluating all data sources and will update this report as more information becomes available.
(12) Volcanic cloud height: None detected yet.
(13) Other volcanic cloud information: n/a
(14) Remarks: Please see the NWS AAWU at http://www.weather.gov/aawu/sigmets for updated information on aviation warning messages.
(15) Contacts: Chris Waythomas, Acting Scientist-in-Charge, USGS
chris@usgs.gov (907) 786-7497

Jeff Freymueller, Coordinating Scientist, UAFGI
jfreymueller@alaska.edu (907) 322-4085
(16) Next Notice:
2017-07-10 - Bogoslof, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170710/1840Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: ORANGE
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: An eruption began at Bogoslof volcano at 18:00 UTC on July 10 (10:00 AKDT on July 10) and lasted 8 minutes. No ash cloud has been detected as of yet in satellite data, but volcanic ash emissions are likely occurring based on infrasound data. Winds are towards the southeast. Ash trajectory models indicate that a possible trace ash fall could occur on Unalaska, but unlikely to affect Dutch Harbor.

We are evaluating the magnitude of this eruptive episode. The Aviation Color Code remains at ORANGE and the Volcano Alert Level remains at WATCH at present. AVO is evaluating all data sources and will update this report as more information becomes available.
(12) Volcanic cloud height: None detected yet.
(13) Other volcanic cloud information: n/a
(14) Remarks: Please see the NWS AAWU at http://www.weather.gov/aawu/sigmets for updated information on aviation warning messages.
(15) Contacts: Chris Waythomas, Acting Scientist-in-Charge, USGS
chris@usgs.gov (907) 786-7497

Pavel Izbekov, Acting Coordinating Scientist, UAF
GIpavel@gi.alaska.edu (907) 322-4085

(16) Next Notice:
2017-07-10 - Bogoslof, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170710/1610Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: ORANGE
(5) Previous Color Code: RED
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: No further ash emissions have occurred at Bogoslof Volcano since the series of explosions that began on Sunday, 09 July at 23:47 AKDT (07:47 UTC July 10) and ended about 02:35 AKDT (10:35 UTC) July 10. A small eruption cloud associated with the first two eruptive pulses was evident in satellite data. This cloud may have reached as high as 20,000 ft. above sea level and was carried to the southeast but dissipated rapidly. No additional volcanic clouds were observed in satellite data. The activity also was detected in seismic and infrasound data. After about 03:00 AKDT (11:00 UTC) seismicity declined and has remained at low levels. We are therefore lowering the Aviation Color Code to ORANGE and the Alert Level to WATCH. Given the ongoing episodic nature of eruptive activity at Bogoslof, additional ash-producing eruptions could occur at any time.
(12) Volcanic cloud height: Not applicable
(13) Other volcanic cloud information: Not applicable
(14) Remarks:
(15) Contacts: Chris Waythomas, Acting Scientist-in-Charge, USGS
chris@usgs.gov (907) 786-7497

Pavel Izbekov, Acting Coordinating Scientist, UAF
GIpavel@gi.alaska.edu (907) 322-4085

(16) Next Notice:
2017-07-10 - Bogoslof, Aviation Color Code: RED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170710/0851Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: RED
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: An eruption began at Bogoslof volcano at 07:47 UTC on July 9 (23:47 AKDT on July 9) lasting about 5 minutes followed 15 minutes later by a second explosion that lasted about 7 minutes. A small ash cloud has been detected in satellite data. Winds are towards the southeast. The Aviation Color Code is upgraded to RED and the Volcano Alert Level to WARNING. Ash trajectory models indicate that a possible trace ash fall could occur on Unalaska, but unlikely to affect Dutch Harbor.

(12) Volcanic cloud height: Small cloud detectedt. NWS eruption SIGMET issued to 30,000 ft asl.
(13) Other volcanic cloud information: n/a
(14) Remarks: The National Weather Service Alaska Aviation Weather Unit has issued an eruption SIGMET warning for aviation up to 30,000 ft above sea level. This may be revised as new information becomes available. Please see the NWS AAWU at http://www.weather.gov/aawu/sigmets for updated information on aviation warning messages.
(15) Contacts: Chris Waythomas, Acting Scientist-in-Charge, USGS
chris@usgs.gov (907) 786-7497

Pavel Izbekov, Acting Coordinating Scientist, UAF
GIpavel@gi.alaska.edu (907) 322-4085

(16) Next Notice:
2017-07-09 - Bogoslof, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170709/1524Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: ORANGE
(5) Previous Color Code: RED
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: No further ash emissions have occurred at Bogoslof Volcano since the explosion on Saturday, 08 July at 10:15 AKDT (18:15 UTC) and seismicity remains low. We are therefore lowering the Aviation Color Code to ORANGE and the Alert Level to WATCH. Additional ash-producing eruptions could occur at any time, however, with no detectable precursors.
(12) Volcanic cloud height: Not applicable
(13) Other volcanic cloud information: Not applicable
(14) Remarks:
(15) Contacts: Chris Waythomas, Acting Scientist-in-Charge, USGS
chris@usgs.gov (907) 786-7497

Pavel Izbekov, Acting Coordinating Scientist, UAF
GIpavel@gi.alaska.edu (907) 322-4085

(16) Next Notice:
2017-07-08 - Bogoslof, Aviation Color Code: RED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170708/1901Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: RED
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: Two short duration eruption pulses were detected in seismic data. The first began at 18:15 UTC (10:15 AKDT) that lasted about 9 minutes, followed by a shorter pulse at 18:29 UTC (10:29 AKDT). The cloud has been observed in satellite data at an estimated height of 30,000 ft asl. The Aviation Color Code is being increased to Red and the Alert Level to Warning.

Seismic data has decreased following these two eruption pulses, but additional explosive activity is possible. Winds are towards the north over the Bering sea, and ashfall on populated islands is not likely. The National Weather Service has issued an eruption SIGMET warning for aviation with an eruption cloud height of 30,000 ft. This may be revised as new satellite data becomes available. See http://www.weather.gov/aawu/sigmets for the most current information.
(12) Volcanic cloud height: 30,000 ft based on satellite data.
(13) Other volcanic cloud information: Winds are towards the north
(14) Remarks:
(15) Contacts: Chris Waythomas, Acting Scientist-in-Charge, USGS
chris@usgs.gov (907) 786-7497

Pavel Izbekov, Acting Coordinating Scientist, UAF
GIpavel@gi.alaska.edu (907) 322-4085

(16) Next Notice:
2017-07-05 - Bogoslof, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170705/1835Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: ORANGE
(5) Previous Color Code: RED
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: No further ash emissions have occurred at Bogoslof Volcano since the explosion on Tuesday, 04 July at 19:07 AKDT (03:07 UTC 05 July) and seismicity remains low. We are therefore lowering the Aviation Color Code to ORANGE and the Alert Level to WATCH. Additional ash-producing eruptions could occur at any time, however, with no detectable precursors.
(12) Volcanic cloud height: Not applicable
(13) Other volcanic cloud information: Not applicable
(14) Remarks:
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Mike West, Acting Coordinating Scientist, UAFGI
mewest@alaska.edu (907) 322-4085
(16) Next Notice:
2017-07-05 - Bogoslof, Aviation Color Code: RED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170705/0328Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: RED
(5) Previous Color Code: RED
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: Another eruption began at Bogoslof at 19:07 AKDT July 4 (03:07 UTC, July 5) that lasted about 11 minutes and was detected in seismic and infrasound data. There are no satellite data yet available. Winds are generally to the southeast. The Aviation Color Code/Alert Level remains at RED/WARNING.
(12) Volcanic cloud height: Unknown
(13) Other volcanic cloud information: Winds are to southeast
(14) Remarks: Status of the ash cloud forecast can be found at the National Weather Service Alaska Aviation Weather Unit website at http://aawu.arh.noaa.gov/
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Mike West, Acting Coordinating Scientist, UAFGI
mewest@alaska.edu (907) 322-4085
(16) Next Notice:
2017-07-05 - Bogoslof, Aviation Color Code: RED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170705/0135Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: RED
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: An eruption began at Bogoslof at 16:51 AKDT July 4 (00:51 UTC, July 5) that lasted 13 minutes and was detected in seismic, infrasound, and satellite data. Winds are generally to the southeast, and initial satellite data suggest the cloud may be as high as 32,000 ft asl. AVO is raising the Aviation Color Code/Alert Level to RED/WARNING.
(12) Volcanic cloud height: 32,000 ft asl
(13) Other volcanic cloud information: Winds are to southeast
(14) Remarks: NWS has issued a SIGMET to 32,000 ft.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Mike West, Acting Coordinating Scientist, UAFGI
mewest@alaska.edu (907) 322-4085
(16) Next Notice:
2017-07-04 - Cleveland, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170704/1205Z)
(3) Volcano: Cleveland (VNUM #311240)
(4) Current Color Code: ORANGE
(5) Previous Color Code: YELLOW
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 52 deg 49 min W 169 deg 56 min
(9) Area: Aleutians
(10) Summit Elevation: 5676 ft (1730 m)
(11) Volcanic Activity Summary: A moderate, 10-minute-long eruption occurred at Cleveland Volcano beginning at 03:19 AKDT (11:19 UTC) on 4 July. The explosion was detected by seismic and infrasound (air pressure) sensors. No satellite data is currently available. We are elevating the Aviation Color Code/Alert Level to ORANGE/WATCH.
(12) Volcanic cloud height: N/A
(13) Other volcanic cloud information: N/A
(14) Remarks: Cleveland volcano is not monitored with a full real-time seismic network and this inhibits AVO's ability to detect unrest that may lead to future activity. We are able to detect explosive activity using infrasound and limited seismic instruments on the island.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Mike West, Acting Coordinating Scientist, UAFGI
mewest@alaska.edu (907) 322-4085
(16) Next Notice:
2017-07-03 - Bogoslof, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170703/1637Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: ORANGE
(5) Previous Color Code: RED
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: No further ash emissions have occurred at Bogoslof Volcano since the explosion on Sunday, 02 July at 12:48 AKDT (20:48 UTC) and seismicity remains low. We are therefore lowering the Aviation Color Code to ORANGE and the Alert Level to WATCH. Additional ash-producing eruptions could occur at any time, however, with no detectable precursors.
(12) Volcanic cloud height: Not applicable
(13) Other volcanic cloud information: Not applicable
(14) Remarks:
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Mike West, Acting Coordinating Scientist, UAFGI
mewest@alaska.edu (907) 322-4085
(16) Next Notice:
2017-07-02 - Bogoslof, Aviation Color Code: RED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170702/2147Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: RED
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: A significant explosive eruption occurred at 20:48 UTC July 2 (12:48 AKDT July 2). AVO is raising the Aviation Color Code to RED and Alert level to WARNING for Bogoslof volcano.

Satellite data and pilot reports shows a volcanic cloud with an estimated altitude of 36,000 ft asl moving towards the east. Seismic and infrasound data suggest that the ash emissions are no longer continuing.
(12) Volcanic cloud height: 36,000 ft asl estimated by satellite and pilot report
(13) Other volcanic cloud information: Cloud moving towards east
(14) Remarks: The SIGMET warning message for aviation, issued by the National Weather Service Alaska Aviation Weather Unit, currently is in effect up to 36,000 ft above sea level. Status of the ash cloud forecast can be found at their website at http://aawu.arh.noaa.gov/

See http://www.weather.gov/afc/ for details on possible ash fall on communities.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Mike West, Acting Coordinating Scientist, UAFGI
mewest@alaska.edu (907) 322-4085
(16) Next Notice:
2017-07-02 - Bogoslof, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170702/2119Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: ORANGE
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: An eruption began at Bogoslof volcano at 20:48 UTC on July 02 (12:48 AKDT on July 2). Eruption seismicity had declined by 21:04 UTC (13:04 AKDT). No ash cloud has been detected as of yet in satellite data, but volcanic ash emissions likely occurred based on infrasound data. Winds are towards the east.

The Aviation Color Code remains at ORANGE and the Volcano Alert Level remains at WATCH at present. AVO is evaluating all data sources and will update this report as more information becomes available.
(12) Volcanic cloud height: None detected yet. NWS eruption SIGMET issued.
(13) Other volcanic cloud information: Winds towards east
(14) Remarks: The National Weather Service Alaska Aviation Weather Unit has issued an eruption SIGMET warning for aviation. This may be revised as new information becomes available. Please see the NWS AAWU at http://www.weather.gov/aawu/sigmets for updated information on aviation warning messages.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Mike West, Acting Coordinating Scientist, UAFGI
mewest@alaska.edu (907) 322-4085
(16) Next Notice:
2017-06-30 - Bogoslof, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170630/0155Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: ORANGE
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: An eruption began at Bogoslof volcano at 01:24 UTC on June 30 (17:24 AKDT on June 29). Seismicity returned to background at 01:45 UTC (17:45 AKDT) indicating an end or pause to the explosion. No ash cloud has been detected as of yet in satellite data, but infrasound signals recorded from Bogoslof suggest volcanic ash emissions likely occurred. Winds are towards the north.

We are evaluating the magnitude of this eruptive episode. The Aviation Color Code remains at ORANGE and the Volcano Alert Level remains at WATCH at present. AVO is evaluating all data sources and will update this report as more information becomes available.
(12) Volcanic cloud height: None detected yet. NWS eruption SIGMET issued. Unknown height
(13) Other volcanic cloud information: Winds to the north
(14) Remarks: The National Weather Service Alaska Aviation Weather Unit has issued an eruption SIGMET warning for aviation. This may be revised as new information becomes available. Please see the NWS AAWU at http://www.weather.gov/aawu/ for updated information on aviation warning messages.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jeff Freymueller, Coordinating Scientist, UAF
jfreymueller@alaska.edu (907) 322-4085
(16) Next Notice:
2017-06-27 - Bogoslof, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170627/2336Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: ORANGE
(5) Previous Color Code: RED
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: No further ash emissions have occurred at Bogoslof Volcano since the explosion on June 27 at 03:17 AKDT (11:17 UTC) and seismicity remains low. We are therefore lowering the Aviation Color Code to ORANGE and the Alert Level to WATCH. Additional ash-producing eruptions could occur at any time, however, with no detectable precursors.
(12) Volcanic cloud height: Not applicable
(13) Other volcanic cloud information: Not applicable
(14) Remarks:
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jeff Freymueller, Coordinating Scientist, UAF
jfreymueller@alaska.edu (907) 322-4085
(16) Next Notice:
2017-06-27 - Bogoslof, Aviation Color Code: RED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170627/1152Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: RED
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: A significant explosive eruption began at Bogoslof volcano at 11:17 UTC on June 27 (03:17 AKDT) as indicated in seismic and lighting data and is continuing. Although at this time there have been no satellite images or pilot reports received confirming eruptive activity, these monitoring data strongly suggest that significant ash emissions have occurred. Thus, AVO is raising the Aviation Color Code to RED and Alert level to WARNING.

AVO is evaluating all data sources and will update this report as more information becomes available.
(12) Volcanic cloud height: None detected yet. NWS eruption SIGMET issued to 30,000 ft asl.
(13) Other volcanic cloud information: Wind direction to the northeast
(14) Remarks: The National Weather Service Alaska Aviation Weather Unit has issued an eruption SIGMET warning for aviation up to 30,000 ft above sea level. This may be revised as new information becomes available. Please see the NWS AAWU at http://www.weather.gov/aawu/sigmets for updated information on aviation warning messages.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jeff Freymueller, Coordinating Scientist, UAF
jfreymueller@alaska.edu (907) 322-4085
(16) Next Notice:
2017-06-27 - Bogoslof, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170627/0248Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: ORANGE
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: Seismicity for the eruption at Bogoslof volcano at 00:45 UTC on June 27 (16:45 AKDT on June 26) remained elevated until 00:59 UTC (16:59 AKDT) and has since declined to background levels. The eruption produced a volcanic cloud moving northeast with an estimated altitude of 25,000 ft asl by satellite data, and a pilot reported a visible cloud at 22,000 ft asl. Given the lower altitude of the volcanic cloud and short duration of the explosion, the Aviation Color Code remains ORANGE and Volcano Alert Level WATCH.

Recent eruptive episodes have produced multiple short-duration explosions interspersed with minutes to hours of inactivity between events, and future explosions could occur with little to no warning. AVO will continue to monitor seismic and infrasound data from nearby islands, as well as lightning data from the World Wide Lightning Location Network for signs of renewed activity.
(12) Volcanic cloud height: 25,000 ft asl estimated by satellite & pilot report
(13) Other volcanic cloud information: Cloud moving towards northeast
(14) Remarks: The SIGMET warning message for aviation, issued by the National Weather Service Alaska Aviation Weather Unit currently is in effect up to 25,000 ft above sea level. Status of the ash cloud forecast can be found at their website at http://aawu.arh.noaa.gov/
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jeff Freymueller, Coordinating Scientist, UAF
jfreymueller@alaska.edu (907) 322-4085
(16) Next Notice:
2017-06-27 - Bogoslof, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170627/0111Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: ORANGE
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: An eruption began at Bogoslof volcano at 00:45 UTC on June 27 (16:45 AKDT on June 26) and is continuing. No ash cloud has been detected as of yet in satellite data through 00:50 UTC, but volcanic ash emissions are likely occurring based on seismic data. Winds are towards the northeast.

We are evaluating the magnitude of this eruptive episode. The Aviation Color Code remains at ORANGE and the Volcano Alert Level remains at WATCH at present. AVO is evaluating all data sources and will update this report as more information becomes available.
(12) Volcanic cloud height: None detected yet in satellite data through 00:50 UTC.
(13) Other volcanic cloud information: n/a
(14) Remarks: Please see the NWS AAWU at http://www.weather.gov/aawu/sigmets for updated information on aviation warning messages should they be issued.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jeff Freymueller, Coordinating Scientist, UAF
jfreymueller@alaska.edu (907) 322-4085
(16) Next Notice:
2017-06-26 - Cleveland, Aviation Color Code: YELLOW (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170626/2006Z)
(3) Volcano: Cleveland (VNUM #311240)
(4) Current Color Code: YELLOW
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 52 deg 49 min W 169 deg 56 min
(9) Area: Aleutians
(10) Summit Elevation: 5676 ft (1730 m)
(11) Volcanic Activity Summary: Recent observations of Cleveland Volcano suggest that unrest has declined and it is unlikely that eruptive activity is continuing. Satellite observations have yielded no evidence for continuing lava effusion and there have been no detections of anomalous seismicity or infrasound from the volcano since a brief explosion on Tuesday evening (May 16) at 19:17 AKDT (03:17 May 17 UTC). Evidence for lava effusion in the summit crater was observed in satellite data on June 7, but since then observed surface temperatures have become weaker, suggesting that lava effusion has paused or ended.

The overall decline in unrest and lack of evidence for lava effusion warrants downgrading the Aviation Color Code to YELLOW and the Volcano Alert Level to ADVISORY.
(12) Volcanic cloud height: N/A
(13) Other volcanic cloud information: N/A
(14) Remarks: Cleveland volcano is not monitored with a full real-time seismic network and this inhibits AVO's ability to detect unrest that may lead to future activity. We are able to detect explosive activity using infrasound and limited seismic instruments on the island.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jeff Freymueller, Coordinating Scientist, UAF
jfreymueller@alaska.edu (907) 322-4085
(16) Next Notice:
2017-06-24 - Bogoslof, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170624/1954Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: ORANGE
(5) Previous Color Code: RED
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: No further explosions or ash emissions have been detected at Bogoslof Volcano since the explosive event at 0:40-0:44 AKDT (8:40-8:44 UTC), June 24. Since then, Bogoslof seismicity has remained low and nothing noteworthy has been detected in satellite, infrasound or lightning data. We are therefore lowering the Aviation Color Code to ORANGE and the Alert Level to WATCH. Additional ash-producing eruptions could occur at any time, and precursory unrest may be minor or not detectable.
(12) Volcanic cloud height: None Observed
(13) Other volcanic cloud information: n/a
(14) Remarks:
(15) Contacts: Dave Schneider, Acting Scientist-in-Charge, USGS
djschneider@usgs.gov (907) 786-7497

Jeff Freymueller, Coordinating Scientist, UAF
jfreymueller@alaska.edu (907) 322-4085
(16) Next Notice:
2017-06-24 - Bogoslof, Aviation Color Code: RED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170624/0220Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: RED
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: A significant explosive eruption at Bogoslof volcano occurred at 00:49 UTC, June 24 (16:49 AKDT, June 23) and lasted about 10 minutes. The eruption produced a volcanic cloud that reached about 36,000 ft above sea level, and was accompanied by strong seismcity, lightning and infrasound. Thus, AVO is raising the Aviation Color Code to RED and Alert level to WARNING for Bogoslof volcano.

Satellite data through 1:30 UTC shows a volcanic cloud with an estimated altitude of 36,000 ft asl moving towards the northeast. Seismic and infrasound data suggest that the ash emissions are no longer continuing. The volcano is in a restless condition and additional explosive events may occur.
(12) Volcanic cloud height: 36,000 ft asl estimated by satellite and pilot report of cloud to 30,000 ft asl.
(13) Other volcanic cloud information: Cloud moving towards northeast
(14) Remarks: The SIGMET warning message for aviation, issued by the National Weather Service Alaska Aviation Weather Unit currently is in effect up to 36,000 ft above sea level. Status of the ash cloud forecast can be found at their website at http://www.weather.gov/aawu/sigmets

No ash fallout is expected in populated areas, as the ash cloud is expected to be transported out over the ocean.
(15) Contacts: Dave Schneider, Acting Scientist-in-Charge, USGS
djschneider@usgs.gov (907) 786-7497

Jeff Freymueller, Coordinating Scientist, UAF
jfreymueller@alaska.edu (907) 322-4085
(16) Next Notice:
2017-06-24 - Bogoslof, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170624/0131Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: ORANGE
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: An explosion was detected in seismic and infrasound data at Bogoslof volcano beginning at 00:49 UTC, June 24 (16:49 AKDT, June 23) and lasting about 10 minutes. A small ash cloud was observed in satellite data starting at 0100 UTC.

We are evaluating the magnitude of this eruptive episode. The Aviation Color Code remains at ORANGE and the Volcano Alert Level remains at WATCH at present. We will update this report as more information becomes available.
(12) Volcanic cloud height: Preliminary SIGMET issued by NWS to 30,000 ft asl.
(13) Other volcanic cloud information: Observed in satellite beginning at 0100 UTC
(14) Remarks: The National Weather Service Alaska Aviation Weather Unit has issued an eruption SIGMET warning for aviation up to 30,000 ft above sea level. This may be revised as new information becomes available. Please see the NWS AAWU at http://www.weather.gov/aawu/sigmets for updated information on aviation warning messages.
(15) Contacts: Dave Schneider, Acting Scientist-in-Charge, USGS
djschneider@usgs.gov (907) 786-7497

Jeff Freymueller, Coordinating Scientist, UAF
jfreymueller@alaska.edu (907) 322-4085
(16) Next Notice:
2017-06-13 - Bogoslof, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170613/2035Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: ORANGE
(5) Previous Color Code: RED
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: No new explosive activity has been observed at Bogoslof volcano since the small explosion this morning at 8:17 AKDT (16:17 UTC). No ash cloud was detected in satellite imagery, likely because it was too small or below our detection limits. The National Weather Service Alaska Aviation Weather Unit did not issue a SIGMET for this mornings event. No detectable activity has been seen in seismic or infrasound data since the explosion. We are therefore, lowering the Aviation Color Code to ORANGE and the Alert Level to WATCH. Additional ash-producing eruptions could occur at any time, however, with no detectable precursors.
(12) Volcanic cloud height: none detected
(13) Other volcanic cloud information: Unknown
(14) Remarks: Status of ash cloud forecasts can be found at the National Weather Service Alaska Aviation Weather Unit website at http://aawu.arh.noaa.gov/
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jeff Freymueller, Coordinating Scientist, UAF
jfreymueller@alaska.edu (907) 322-4085
(16) Next Notice:
2017-06-13 - Bogoslof, Aviation Color Code: RED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170613/1648Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: RED
(5) Previous Color Code: RED
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: A six-minute-long explosion was detected in seismic and infrasound data at 8:17 AKDT (16:17 UTC). There have been no satellite images of a resulting volcanic cloud, and its height is currently unknown. Lower level winds are currently to the northwest, and higher level winds to the southeast, over southern Unalaska Island.

The Aviation Color Code remains at RED and Volcano Alert Level at WARNING.
(12) Volcanic cloud height: unknown
(13) Other volcanic cloud information: Lower-level winds to NW; higher level winds to SE
(14) Remarks: Status of the ash cloud forecast can be found at the National Weather Service Alaska Aviation Weather Unit website at http://aawu.arh.noaa.gov/
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jeff Freymueller, Coordinating Scientist, UAF
jfreymueller@alaska.edu (907) 322-4085
(16) Next Notice:
2017-06-13 - Bogoslof, Aviation Color Code: RED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170613/0340Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: RED
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: The eruption of Bogoslof that began 01:47 UTC June 13 (17:47 AKDT June 12) with a 9-minute duration explosion has resumed starting at 02:57 UTC June 13 (18:57 AKDT June 12) based on seismic and infrasound data.

The ash cloud produced during the initial 9-minute event has been observed in satellite data through 02:20 UTC June 13 (18:20 AKDT June 12) and is estimated to be at about 25,000 feet above sea level drifting SE toward Unalaska Island. Ash emissions from this new activity have yet to be observed but they are likely occurring with winds to the SE. Thus, AVO is raising the Aviation Color Code to RED and Alert level to WARNING for Bogoslof volcano. Activity is ongoing and additional explosive events may occur.
(12) Volcanic cloud height: 25,000 ft asl estimated by satellite data.
(13) Other volcanic cloud information: Cloud moving towards SE
(14) Remarks: The SIGMET warning message for aviation, issued by the National Weather Service Alaska Aviation Weather Unit currently is in effect up to 25,000 ft above sea level. Status of the ash cloud forecast can be found at their website at http://aawu.arh.noaa.gov/

No ash fallout is expected in populated areas, as the ash cloud is expected to be transported out over the ocean. The National Weather Service in has issued a Special Weather Statement for the possibility of a trace amount of ash fallout in Unalaska/Dutch Harbor tonight. See http://www.weather.gov/afc/ for details.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jeff Freymueller, Coordinating Scientist, UAF
jfreymueller@alaska.edu (907) 322-4085
(16) Next Notice:
2017-06-13 - Bogoslof, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170613/0213Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: ORANGE
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: A short-lived eruption of Bogoslof volcano began June 13 at 01:47 UTC (17:47 AKDT June 12) and lasted about 9 minutes according to seismic and infrasound data. No ash cloud has been detected in satellite data yet but a single lightning stroke has been observed, thus volcanic ash emissions are likely occurring. Winds are to the southeast and no ashfall is expected on communities.

We are evaluating the magnitude of this eruptive episode and activity may resume at any time. The Aviation Color Code remains at ORANGE and the Volcano Alert Level remains at WATCH at present. AVO is evaluating all data sources and will update this report as more information becomes available.
(12) Volcanic cloud height: None detected yet. NWS eruption SIGMET issued to 25,000 ft asl.
(13) Other volcanic cloud information: n/a
(14) Remarks: The National Weather Service Alaska Aviation Weather Unit has issued an eruption SIGMET warning for aviation up to 25,000 ft above sea level. This may be revised as new information becomes available. Please see the NWS AAWU at http://www.weather.gov/aawu/sigmets for updated information on aviation warning messages.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jeff Freymueller, Coordinating Scientist, UAF
jfreymueller@alaska.edu (907) 322-4085
(16) Next Notice:
2017-06-10 - Bogoslof, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170610/2301Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: ORANGE
(5) Previous Color Code: RED
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: No further ash emissions have occurred at Bogoslof Volcano since the explosion on Saturday, June 10 at 3:18 AKDT (11:18 UTC) and seismicity remains low. We are therefore lowering the Aviation Color Code to ORANGE and the Alert Level to WATCH. Additional ash-producing eruptions could occur at any time, however, with no detectable precursors.
(12) Volcanic cloud height: Not applicable
(13) Other volcanic cloud information: Not applicable
(14) Remarks: Please see the NWS AAWU at http://www.weather.gov/aawu/sigmets for updated information on aviation warning messages.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jessica Larsen, Acting Coordinating Scientist, UAF
jflarsen@alaska.edu (907) 322-4085
(16) Next Notice:
2017-06-10 - Bogoslof, Aviation Color Code: RED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170610/1303Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: RED
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: An explosive eruption is detected in multiple data streams. Small explosions were first observed on infrasound stations located on nearby Islands beginning at 11:18 UTC (3:18 AKDT). Activity transitioned to continuous seismic tremor at about 12:16 UTC and is ongoing. An eruption cloud has been observed in satellite data and lightning has been detected. AVO is raising the Aviation Color Code to RED and the Volcano Alert Level remains at WARNING. More information will be released as it becomes available.
(12) Volcanic cloud height: 30,000 ft estimate at 12:20 UTC
(13) Other volcanic cloud information: Winds are generally northward
(14) Remarks: The National Weather Service has issued a SIGMET for this eruption to 30,000 ft asl. Please check their information at http://www.weather.gov/aawu/ as this is an evolving situation and cloud height may change.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jessica Larsen, Acting Coordinating Scientist, UAF
jflarsen@alaska.edu (907) 322-4085
(16) Next Notice:
2017-06-08 - Bogoslof, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170608/0605Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: ORANGE
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: A short duration explosive event occurred at Bogoslof volcano at 5:28 UTC on 8 June (21:28 AKDT on 7 June). Seismic and infrasound signals indicate that this event was very similar to the event from earlier today at 14:30 UTC. The duration of the event was less than 2 minutes, and seismicity and infrasound returned to low levels following the explosion. A small steam-rich volcanic cloud is visible in satellite data, rising no more than 10,000 ft asl. Due to the brevity of the event, the Aviation Color Code remains at ORANGE and the Volcano Alert Level remains at WATCH.
(12) Volcanic cloud height: 10,000 ft asl
(13) Other volcanic cloud information: White in visible wavelength satellite data.
(14) Remarks: The National Weather Service has issued a SIGMET warning for aviation for a volcanic cloud up to 10,000 ft asl. See http://www.weather.gov/aawu/sigmets for updated information.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jessica Larsen, Acting Coordinating Scientist, UAF
jflarsen@alaska.edu (907) 322-4085
(16) Next Notice:
2017-06-08 - Bogoslof, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170608/0025Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: ORANGE
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: A new lava dome has been observed in satellite data from earlier today. It is located in the northern portion of the vent lagoon, has breached sea level, and is about 110 m across. A robust steam plume is visible in satellite data, and at 2250 UTC (14:50 AKDT) extended for 75 km to the south over the western end of Unalaska Island at an estimated altitude of less than 10,000 ft asl.

Some past eruptions of Bogoslof have ended with the emplacement of a lava dome, but in other cases, lava effusion has been followed by additional explosions. If future explosions do occur, the resulting volcanic cloud could be more ash-rich than those that have occurred thus far in the sequence that began in 2016.

This level of activity is consistent with the current Aviation Color Code of ORANGE and the Volcano Alert Level of WATCH.
(12) Volcanic cloud height: Less than 10,000 ft asl
(13) Other volcanic cloud information: Steam-rich
(14) Remarks:
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jessica Larsen, Acting Coordinating Scientist, UAF
jflarsen@alaska.edu (907) 322-4085
(16) Next Notice:
2017-06-07 - Pavlof, Aviation Color Code: YELLOW (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170607/2303Z)
(3) Volcano: Pavlof (VNUM #312030)
(4) Current Color Code: YELLOW
(5) Previous Color Code: GREEN
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 55 deg 25 min W 161 deg 53 min
(9) Area: Alaska Peninsula
(10) Summit Elevation: 8261 ft (2518 m)
(11) Volcanic Activity Summary: Over the past several days, there has been an increase in low-frequency earthquake activity at Pavlof. Such increases are sometimes seen prior to eruptive episodes, however in other cases they decline without eruptive activity. In addition, several short duration tremor-bursts have been observed today, and AVO received a pilot report of a possible ash cloud this afternoon. Infrasound data from local instruments on Pavlof and from a more distant network in Sand Point do not show any evidence of significant explosive activity. Precursory activity prior to eruptions of Pavlof are always very subtle, thus, on the basis of these observations we are increasing the Aviation Color Code to Yellow and the Alert Level to Advisory.
(12) Volcanic cloud height: 4000 ft. Pilot report of possible ash cloud.
(13) Other volcanic cloud information: Possible cloud not coming from vent, but drifting downwind.
(14) Remarks: Pavlof Volcano is a snow- and ice-covered stratovolcano located on the southwestern end of the Alaska Peninsula about 953 km (592 mi) southwest of Anchorage. The volcano is about 7 km (4.4 mi) in diameter and has active vents on the north and east sides close to the summit. With over 40 historic eruptions, it is one of the most consistently active volcanoes in the Aleutian arc. Eruptive activity is generally characterized by sporadic Strombolian lava fountaining continuing for a several-month period. Ash plumes as high as 49,000 ft ASL have been generated by past eruptions of Pavlof, and during the March 2016 eruption, ash plumes as high as 40,000 feet above sea level were generated and the ash was tracked in satellite data as distant as eastern Canada. The nearest community, Cold Bay, is located 60 km (37 miles) to the southwest of Pavlof.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jessica Larsen, Acting Coordinating Scientist, UAF
jflarsen@alaska.edu (907) 322-4085
(16) Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at
http://www.avo.alaska.edu
2017-06-07 - Bogoslof, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170607/1505Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: ORANGE
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: A short duration explosive event occurred at Bogoslof volcano at 14:30 UTC on June 7 (6:30 am AKDT). Seismic signals indicate that this event was slightly larger than a similar explosion detected at Bogoslof yesterday morning The duration of the event was about 2 minutes, and seismicity returned to low levels following the explosion. No volcanic cloud has been seen in satellite data as of 14:30 UTC. Due to the brevity of the event, the Aviation Color Code remains at ORANGE and the Volcano Alert Level remains at WATCH.

This level of activity is consistent with the current Aviation Color Code of ORANGE and the Volcano Alert Level of WATCH.
(12) Volcanic cloud height: None observed in satellite data through 14:30 UTC
(13) Other volcanic cloud information: Unknown
(14) Remarks:
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jessica Larsen, Acting Coordinating Scientist, UAF
jflarsen@alaska.edu (907) 322-4085
(16) Next Notice:
2017-06-06 - Bogoslof, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170606/1445Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: ORANGE
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: A short duration explosive event occurred at Bogoslof volcano at 14:00 UTC on June 6 (6:00 am AKDT) The duration of the event was less than 2 minutes, and seismicity returned to low levels following the explosion. No cloud from this event was observed in satellite data. Due to the brevity of the event, the Aviation Color Code remains at ORANGE and the Volcano Alert Level remains at WATCH.

This level of activity is consistent with the current Aviation Color Code of ORANGE and the Volcano Alert Level of WATCH.
(12) Volcanic cloud height: None Observed
(13) Other volcanic cloud information: Unknown
(14) Remarks:
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jessica Larsen, Acting Coordinating Scientist, UAF jflarsen@alaska.edu (907) 322-4085
(16) Next Notice:
2017-06-05 - Bogoslof, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170605/2215Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: ORANGE
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: Low amplitude seismic tremor from Bogoslof Volcano was detected in seismic data beginning at about 20:29, June 5 UTC (12:29 AKST) and has since decreased to background levels. A USF&WS vessel in the vicinity reported vigorous steaming and a "white plume" rising several thousand feet above sea level. This cloud was too small to be observed in satellite images. Earlier today, a short duration explosive event occurred at Bogoslof (15:50 UTC, June 5) and produced a small volcanic cloud that was observed by a pilot. These events are near the lower level of detection threshold based on current monitoring capabilities and reinforce the hazard that continues to exist in the vicinity of Bogolsof volcano.

This level of activity is consistent with the current Aviation Color Code of ORANGE and the Volcano Alert Level of WATCH.
(12) Volcanic cloud height: Several thousand feet asl.
(13) Other volcanic cloud information: Visual observation.
(14) Remarks:
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jessica Larsen, Acting Coordinating Scientist, UAF jflarsen@alaska.edu (907) 322-4085
(16) Next Notice:
2017-06-05 - Bogoslof, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170605/1630Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: ORANGE
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: A short duration explosive event occurred at Bogoslof volcano at 15:50 UTC on June 5 (7:50 am AKDT) and produced a small volcanic cloud that was observed by a pilot. Winds are transporting the cloud towards the south at an estimated altitude of 20,000 ft asl. The duration of the event was less than 2 minutes, and seismicity returned to low levels following the explosion.

Due to the brevity of the event, the Aviation Color Code remains at ORANGE and the Volcano Alert Level remains at WATCH.
(12) Volcanic cloud height: 20,000 ft asl
(13) Other volcanic cloud information: NWS eruption SIGMET issued.
(14) Remarks: The National Weather Service Alaska Aviation Weather Unit has issued an eruption SIGMET warning for aviation up to 20,000 ft above sea level. Please see the NWS AAWU at http://www.weather.gov/aawu/sigmets for updated information on aviation warning messages.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jessica Larsen, Acting Coordinating Scientist, UAF jflarsen@alaska.edu (907) 322-4085
(16) Next Notice:
2017-06-01 - Bogoslof, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170601/0451Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: ORANGE
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: An short duration explosive event occurred at Bogoslof volcano at 2:42 UTC on June 1 (6:42 AKDT on May 31) and produced a small volcanic ash cloud that was observed in satellite data. Winds are transporting the cloud towards the northwest at an estimated altitude of 23,000 ft asl. The duration of the event was less than 10 minutes, and seismicity returned to low levels following the explosion.

Due to the brevity of the event, the Aviation Color Code remains at ORANGE and the Volcano Alert Level remains at WATCH.
(12) Volcanic cloud height: 23,000 ft asl
(13) Other volcanic cloud information: NWS eruption SIGMET issued.
(14) Remarks: The National Weather Service Alaska Aviation Weather Unit has issued an eruption SIGMET warning for aviation up to 23,000 ft above sea level. Please see the NWS AAWU at http://www.weather.gov/aawu/sigmets for updated information on aviation warning messages.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jessica Larsen, Acting Coordinating Scientist, UAF
jflarsen@alaska.edu (907) 322-4085
(16) Next Notice:
2017-05-29 - Bogoslof, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170529/0509Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: ORANGE
(5) Previous Color Code: RED
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: No further ash emissions have occurred at Bogoslof Volcano since the explosion on Sunday, 28 May at 14:16 AKDT (22:16 UTC) and seismicity remains low. We are therefore lowering the Aviation Color Code to ORANGE and the Alert Level to WATCH. Additional ash-producing eruptions could occur at any time, however, with no detectable precursors.
(12) Volcanic cloud height: Not applicable
(13) Other volcanic cloud information: Not applicable
(14) Remarks:
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jeff Freymueller, Coordinating Scientist, UAFGI
jfreymueller@alaska.edu (907) 322-4085
(16) Next Notice:
2017-05-28 - Bogoslof, Aviation Color Code: RED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170528/2249Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: RED
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: An eruption began at Bogoslof volcano today at about 14:16 AKDT (22:16 UTC May 28) and is continuing based on seismic data. No ash cloud has been detected as of yet in satellite data, but volcanic ash emissions are occurring on the basis of lightning detections. Thus, AVO is raising the Aviation Color Code to RED and Alert level to WARNING. Winds are towards the northwest.

AVO is evaluating all data sources and will update this report as more information becomes available.
(12) Volcanic cloud height: None observed yet.
(13) Other volcanic cloud information: Winds to northwest
(14) Remarks: Please see the NWS AAWU at http://www.weather.gov/aawu/sigmets for updated information on aviation warning messages.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jeff Freymueller, Coordinating Scientist, UAFGI
jfreymueller@alaska.edu (907) 322-4085
(16) Next Notice:
2017-05-17 - Bogoslof, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170517/1908Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: ORANGE
(5) Previous Color Code: RED
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: No further ash emissions have occurred at Bogoslof Volcano since the explosion on Tuesday, 16 May at 22:32 AKDT (06:32 UTC) and seismicity remains low. We are therefore lowering the Aviation Color Code to ORANGE and the Alert Level to WATCH. Additional ash-producing eruptions could occur at any time, however, with no detectable precursors.
(12) Volcanic cloud height: Not applicable
(13) Other volcanic cloud information: Not applicable
(14) Remarks:
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Pavel Izbekov, Acting Coordinating Scientist, UAFGI
pavel@gi.alaska.edu (907) 322-4085
(16) Next Notice:
2017-05-17 - Bogoslof, Aviation Color Code: RED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170517/0726Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: RED
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: The explosive eruption that started today, May 16, around 22:32 AKST (May 17 06:32 UTC) is continuing. A pilot reported that the eruption has produced an ash cloud as high as 34,000 ft asl, and the Worldwide Lightning Location Network has detected lightning associated with the cloud. Winds are currently to the south. Ash has not yet been detected in satellite.

We are raising the Aviation Color Code to RED and Volcano Alert Level to WARNING.
(12) Volcanic cloud height: PIREP to 34,000 ft asl
(13) Other volcanic cloud information: winds are to the south
(14) Remarks: Please see the NWS AAWU at http://www.weather.gov/aawu/sigmets for updated information on aviation warning messages.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Pavel Izbekov, Acting Coordinating Scientist, UAFGI
pavel@gi.alaska.edu (907) 322-4085
(16) Next Notice:
2017-05-17 - Bogoslof, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170517/0700Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: ORANGE
(5) Previous Color Code: YELLOW
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: An increase in seismic and infrasound activity from Bogoslof was detected from stations on nearby islands starting today, May 16, around 22:32 AKST (May 17 06:32 UTC) and is continuing. We have no satellite observations yet, but the infrasound signal suggests an explosive eruption has likely begun. No lightning has been detected. AVO is raising the Aviation Color Code for Bogoslof to ORANGE and the Volcano Alert Level to WATCH.

We will provide more information as it becomes available including any information about a resulting ash cloud.

Bogolsof is not monitored by a real-time seismic network and this inhibits AVO's ability to detect unrest that may lead to an explosive eruption. Rapid detection of an ash-producing eruption may be possible using a combination of data from seismic and infrasound networks on neighboring islands and satellite and lightning detection data.
(12) Volcanic cloud height: not available
(13) Other volcanic cloud information: winds are to the south
(14) Remarks:
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Pavel Izbekov, Acting Coordinating Scientist, UAFGI
pavel@gi.alaska.edu (907) 322-4085
(16) Next Notice:
2017-04-24 - Cleveland, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170424/1943Z)
(3) Volcano: Cleveland (VNUM #311240)
(4) Current Color Code: ORANGE
(5) Previous Color Code: YELLOW
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 52 deg 49 min W 169 deg 56 min
(9) Area: Aleutians
(10) Summit Elevation: 5676 ft (1730 m)
(11) Volcanic Activity Summary: Recent satellite images show a new lava dome has been extruded in the summit crater of Cleveland. The dome began growing sometime after the most recent explosion on March 31. Slightly elevated surface temperatures have been observed in satellite images for the past couple of weeks. The first visual indication of new dome growth was observed in satellite images on April 15 with the presence of a small (less than 10-meter-diameter) mound deep in the March 31 crater. By April 23, this mound had grown to 45 meters in diameter. Dome growth has occurred with no obvious detectable seismicity. The presence of a growing lava dome in the summit crater of Cleveland prompts AVO to raise the Aviation Color Code to ORANGE and the Volcano Alert Level to WATCH.
(12) Volcanic cloud height: N/A
(13) Other volcanic cloud information: N/A
(14) Remarks: Cleveland volcano is not monitored with a full real-time seismic network and this inhibits AVO's ability to detect unrest that may lead to future activity. We are able to detect explosive activity using infrasound and limited seismic instruments on the island.
(15) Contacts: Chris Waythomas, Acting Scientist-in-Charge, USGS
chris@usgs.gov (907) 786-7497

Jeff Freymueller, Coordinating Scientist, UAFGI
jfreymueller@alaska.edu (907) 322-4085
(16) Next Notice:
2017-04-19 - Bogoslof, Aviation Color Code: YELLOW (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170419/2023Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: YELLOW
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: No new volcanic activity has been observed at Bogoslof Volcano in satellite, seismic or infrasound data since a short-lived increase in seismicity on April 15. The last major explosive event occurred on March 8, 2017, and occasional high-spatial resolution satellite images show no significant surficial changes due to eruptive activity since that time. Based on the absence of detected activity over the past several days, AVO is lowering the Aviation Color Code to YELLOW and the Volcano Alert Level to ADVISORY. Bogolsof is not monitored by a real-time seismic network and this inhibits AVO's ability to detect unrest that may lead to an explosive eruption. Rapid detection, and possible forecasting, of an ash-producing eruption may be possible using a combination of data from seismic and infrasound networks on neighboring islands and satellite and lightning detection data.
(12) Volcanic cloud height: N/A
(13) Other volcanic cloud information: N/A
(14) Remarks: Given the lack of a local monitoring network and the unpredictability of the volcano, activity at Bogoslof could ramp up again at any time. Thus a Temporary Flight Restriction (TFR) remains in effect over the volcano for the time being. Please see http://tfr.faa.gov/tfr2/list.html for the status of the TFR.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jessica Larsen, Acting Coordinating Scientist, UAF
jflarsen@alaska.edu (907) 322-4085
(16) Next Notice:
2017-04-16 - Bogoslof, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170416/0320Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: ORANGE
(5) Previous Color Code: YELLOW
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: An increase in earthquake activity from Bogoslof was detected from stations on nearby islands starting April 15 around 15:01 AKST / 23:01 UTC. At this time there has been no evidence of renewed eruptive activity from infrasound, lightning, or satellite data. Similar sequences of earthquakes have preceded some of the explosive events during the ongoing unrest. Because this uptick in seismicity increases the likelihood of future explosive activity, AVO is raising the Aviation Color Code for Bogoslof to ORANGE and the Volcano Alert Level to WATCH.

Bogolsof is not monitored by a real-time seismic network and this inhibits AVO's ability to detect unrest that may lead to an explosive eruption. Rapid detection of an ash-producing eruption may be possible using a combination of data from seismic and infrasound networks on neighboring islands and satellite and lightning detection data.
(12) Volcanic cloud height: N/A
(13) Other volcanic cloud information: N/A
(14) Remarks: Given the lack of a local monitoring network and the unpredictability of the volcano, activity at Bogoslof could ramp up again at any time. Thus a Temporary Flight Restriction (TFR) remains in effect over the volcano for the time being. Please see http://tfr.faa.gov/tfr2/list.html for the status of the TFR.
(15) Contacts: Dave Schneider, Acting Scientist-in-Charge, USGS
djschneider@usgs.gov (907) 786-7497

Jeff Freymueller, Coordinating Scientist, UAFGI jfreymueller@alaska.edu (907) 322-4085
(16) Next Notice:
2017-04-05 - Bogoslof, Aviation Color Code: YELLOW (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170405/1942Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: YELLOW
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: No new volcanic activity has been observed at Bogoslof Volcano in satellite, seismic or infrasound data since a small explosion was detected on March 13. The last major explosive event occurred on March 8, 2017, and occasional high-spatial resolution satellite images show no significant surficial changes due to eruptive activity since that time. Based on the absence of detected activity over the past three weeks, AVO is lowering the Aviation Color Code to YELLOW and the Volcano Alert Level to ADVISORY.

Bogolsof is not monitored by a real-time seismic network and this inhibits AVO's ability to detect unrest that may lead to an explosive eruption. Rapid detection of an ash-producing eruption may be possible using a combination of data from seismic and infrasound networks on neighboring islands and satellite and lightning detection data.
(12) Volcanic cloud height: N/A
(13) Other volcanic cloud information: N/A
(14) Remarks: Given the lack of a local monitoring network and the unpredictability of the volcano, activity at Bogoslof could ramp up again at any time. Thus a Temporary Flight Restriction (TFR) remains in effect over the volcano for the time being. Please see http://tfr.faa.gov/tfr2/list.html for the status of the TFR.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jeff Freymueller, Coordinating Scientist, UAFGI
jfreymueller@alaska.edu (907) 322-4085
(16) Next Notice:
2017-04-05 - Cleveland, Aviation Color Code: YELLOW (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170405/1941Z)
(3) Volcano: Cleveland (VNUM #311240)
(4) Current Color Code: YELLOW
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 52 deg 49 min W 169 deg 56 min
(9) Area: Aleutians
(10) Summit Elevation: 5676 ft (1730 m)
(11) Volcanic Activity Summary: No activity has been observed at Cleveland Volcano since an explosion was detected in seismic and infrasound data on March 24. Recent satellite images show no significant changes to the summit lava dome or crater since late February to early March. Based on seismic levels remaining low and no observations of continued activity, AVO is lowering the Aviation Color Code to YELLOW and the Volcano Alert Level to ADVISORY.
(12) Volcanic cloud height: N/A
(13) Other volcanic cloud information: N/A
(14) Remarks: Cleveland volcano is not monitored with a full real-time seismic network and this inhibits AVO's ability to detect unrest that may lead to future activity. We are able to detect explosive activity using infrasound and limited seismic instruments on the island.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jeff Freymueller, Coordinating Scientist, UAFGI
jfreymueller@alaska.edu (907) 322-4085
(16) Next Notice:
2017-03-24 - Cleveland, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170324/1924Z)
(3) Volcano: Cleveland (VNUM #311240)
(4) Current Color Code: ORANGE
(5) Previous Color Code: YELLOW
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 52 deg 49 min W 169 deg 56 min
(9) Area: Aleutians
(10) Summit Elevation: 5676 ft (1730 m)
(11) Volcanic Activity Summary: A small explosion was detected at Cleveland volcano at 08:15 AKST (16:15 UTC) today in both seismic and infrasound (pressure sensor) data. As a result AVO is increasing the Aviation Color Code to Orange and the Alert Level to Watch. This event was short lived and similar, if not smaller, than recent explosions at this volcano. Cloud cover to 30,000 feet above sea level is obscuring observations of the volcano by satellite views and no ash cloud has been observed. The ash cloud that was likely generated during this explosion has probably dissipated at this time and was likely not above 20,000 feet above sea level.

Cleveland volcano is not monitored with a real-time seismic network and this inhibits AVO's ability to detect unrest that may lead to future activity. We are able to detect explosive activity using infrasound and seismic instruments on the island.
(12) Volcanic cloud height: No volcanic cloud observed.
(13) Other volcanic cloud information: Likely below 20,000 feet above sea level and has likely dissipated at this time.
(14) Remarks:
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jeff Freymueller, Coordinating Scientist, UAFGI
jfreymueller@alaska.edu (907) 322-4085
(16) Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at
http://www.avo.alaska.edu
2017-03-13 - Bogoslof, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170313/1214Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: ORANGE
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: A short-duration eruption began at Bogoslof volcano at 11:31 UTC on March 13 (3:31 AKDT on March 13) and ended 12 minutes later. An ash cloud has been detected in satellite data, and volcanic ash emissions are also likely occurring based on infrasound data. Winds are towards the south-southwest.

We are evaluating the magnitude of this eruptive episode. Although the episode appears to be over and of short duration, additional activity is possible. The Aviation Color Code remains at ORANGE and the Volcano Alert Level remains at WATCH at present. AVO is evaluating all data sources and will update this report as more information becomes available.
(12) Volcanic cloud height: Ash cloud detected. NWS eruption SIGMET issued to 18,000 ft asl.
(13) Other volcanic cloud information: n/a
(14) Remarks: The National Weather Service Alaska Aviation Weather Unit has issued an eruption SIGMET warning for aviation up to 18,000 ft above sea level. This may be revised as new information becomes available. Please see the NWS AAWU at http://www.weather.gov/aawu/sigmets for updated information on aviation warning messages.
(15) Contacts: Dave Schneider, Acting Scientist-in-Charge, USGS
djschneider@usgs.gov (907) 786-7497

Jeff Freymueller, Coordinating Scientist, UAFGI
jfreymueller@alaska.edu (907) 322-4085
(16) Next Notice:
2017-03-09 - Bogoslof, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170309/1701Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: ORANGE
(5) Previous Color Code: RED
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: No further ash emissions have occurred at Bogoslof Volcano since the three-hour-long eruption that began on Tuesday, 7 March at 22:36 AKST (07:36 UTC March 8) and seismicity remains low. We are therefore lowering the Aviation Color Code to ORANGE and the Alert Level to WATCH. Additional ash-producing eruptions could occur at any time, however, with no detectable precursors.
(12) Volcanic cloud height: Not applicable
(13) Other volcanic cloud information: Not applicable
(14) Remarks:
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jessica Larsen, Acting Coordinating Scientist, UAF
jflarsen@alaska.edu (907) 322-4085

(16) Next Notice:
2017-03-08 - Cleveland, Aviation Color Code: YELLOW (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170308/2044Z)
(3) Volcano: Cleveland (VNUM #311240)
(4) Current Color Code: YELLOW
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 52 deg 49 min W 169 deg 56 min
(9) Area: Aleutians
(10) Summit Elevation: 5676 ft (1730 m)
(11) Volcanic Activity Summary: No major activity has been observed at Cleveland Volcano since satellite data confirmed the eruption of a small volume lava dome within the summit crater over a month ago. Weakly elevated surface temperatures have been detected in satellite data in recent weeks that are consistent with cooling lava and are not considered to be indicative of new activity. Steaming from the summit crater has also been observed. Satellite images collected over the past few weeks show the small lava dome is not growing in size. Based on seismic levels remaining low and no observations nor reports of continued eruptive activity, AVO is reducing the Aviation color code to YELLOW and the Volcano Alert Level to ADVISORY.

Cleveland volcano is not monitored with a real-time seismic network and this inhibits AVO's ability to detect unrest that may lead to an explosive eruption. Rapid detection of an ash-producing eruption may be possible using a combination of satellite, infrasound, lightning data and local observations. AVO is monitoring the unrest at Cleveland volcano as closely as possible and will release additional information if or when it becomes available.
(12) Volcanic cloud height: No volcanic clouds observed.
(13) Other volcanic cloud information: No cloud observed.
(14) Remarks: Cleveland volcano forms the western portion of Chuginadak Island, a remote and uninhabited island in the east central Aleutians. The volcano is located about 75 km (45 mi) west of the community of Nikolski, and 1500 km (940 mi) southwest of Anchorage. The most recent significant period of eruption began in February, 2001 and produced 3 explosive events that generated ash clouds as high as 39,000 ft above sea level. The 2001 eruption also produced a lava flow and hot avalanche that reached the sea. Since then, Cleveland has been intermittently active producing small lava flows, often followed by explosions that generate small ash clouds generally below 20,000 ft above sea level. These explosions also launch debris onto the slopes of the cone producing hot pyroclastic avalanches and lahars that sometimes reach the coastline.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jessica Larsen, Acting Coordinating Scientist, UAF
jflarsen@alaska.edu (907) 322-4085

(16) Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at
http://www.avo.alaska.edu
2017-03-08 - Bogoslof, Aviation Color Code: RED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170308/0922Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: RED
(5) Previous Color Code: RED
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: A significant explosive eruption that began at Bogoslof volcano at 7:36 UTC on March 8 (10:36 pm AKST on March 7) is continuing, as indicated in seismic, lightning, and infrasound data. The ash cloud from the eruption has been observed to 35,000 feet in satellite images and is heading east. The current Aviation Color Code is RED and Alert level is WARNING.

The National Weather Service is issuing a Special Weather Statement for trace amounts (less than 1 mm) of ashfall on Unalaska Island including the community of Dutch Harbor/Unalaska.

AVO is evaluating all data sources and will update this report as more information becomes available.
(12) Volcanic cloud height: Observed up to 35,000 ft.
(13) Other volcanic cloud information: Height may be revised as new satellite images are received.
(14) Remarks: The National Weather Service Alaska Aviation Weather Unit has issued an eruption SIGMET warning for aviation up to 35,000 ft above sea level. This may be revised as new information becomes available. Please see the NWS AAWU at http://www.weather.gov/aawu/sigmets for updated information on aviation warning messages.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jessica Larsen, Acting Coordinating Scientist, UAF
jflarsen@alaska.edu (907) 322-4085

(16) Next Notice:
2017-03-08 - Bogoslof, Aviation Color Code: RED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170308/0840Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: RED
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: A significant explosive eruption began at Bogoslof volcano at 7:36 UTC on March 8 (10:36 pm AKST on March 7) as indicated in seismic, lightning, and infrasound data. Although at this time there have been no satellite images confirming eruptive activity, these monitoring data strongly suggest that significant ash emissions have occurred. Thus, AVO is raising the Aviation Color Code to RED and Alert level to WARNING.

AVO is evaluating all data sources and will update this report as more information becomes available.
(12) Volcanic cloud height: None observed yet. Preliminary eruption SIGMET issued by NWS up to 20,000 ft asl.
(13) Other volcanic cloud information: not available
(14) Remarks: The National Weather Service Alaska Aviation Weather Unit has issued an eruption SIGMET warning for aviation up to 20,000 ft above sea level. This may be revised as new information becomes available. Please see the NWS AAWU at http://www.weather.gov/aawu/sigmets for updated information on aviation warning messages.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jessica Larsen, Acting Coordinating Scientist, UAF
jflarsen@alaska.edu (907) 322-4085

(16) Next Notice:
2017-03-08 - Bogoslof, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170308/0825Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: ORANGE
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: An eruption began at Bogoslof volcano at 7:36 UTC on March 8 (10:36 pm AKST on March 7) and is continuing. No ash cloud has been detected as of yet in satellite data, but volcanic ash emissions are likely occurring based on lightning and infrasound data. Winds are towards the east.

We are evaluating the magnitude of this eruptive episode. The Aviation Color Code remains at ORANGE and the Volcano Alert Level remains at WATCH at present. AVO is evaluating all data sources and will update this report as more information becomes available.
(12) Volcanic cloud height: None detected yet. NWS SIGMET issued to 20,000 ft
(13) Other volcanic cloud information: n/a
(14) Remarks: The National Weather Service Alaska Aviation Weather Unit has issued an eruption SIGMET warning for aviation up to 20,00 ft above sea level. This may be revised as new information becomes available. Please see the NWS AAWU at http://www.weather.gov/aawu/sigmets for updated information on aviation warning messages.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jessica Larsen, Acting Coordinating Scientist, UAF
jflarsen@alaska.edu (907) 322-4085

(16) Next Notice:
2017-02-21 - Bogoslof, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170221/2137Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: ORANGE
(5) Previous Color Code: RED
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: No further ash emissions have occurred at Bogoslof Volcano since the explosion on Sunday, 19 February at 17:45 AKST (February 20 02:45 UTC) and seismicity remains low. We are therefore lowering the Aviation Color Code to ORANGE and the Alert Level to WATCH. Additional ash-producing eruptions could occur at any time, however, with no detectable precursors.
(12) Volcanic cloud height: Not applicable
(13) Other volcanic cloud information: Not applicable
(14) Remarks:
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jeff Freymueller, Coordinating Scientist, UAFGI
jfreymueller@alaska.edu (907) 322-4085
(16) Next Notice:
2017-02-20 - Bogoslof, Aviation Color Code: RED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170220/0307Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: RED
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: A significant explosive eruption began at Bogoslof volcano at 02:08 UTC on 20 February (17:08 AKST on 19 February). Seismic and infrasound data show a series of short-lived explosive pulses through 02:45 UTC; seismicity has been quiet since then. Recent satellite images show a cloud as high as 25,000 ft asl. Thus, AVO is raising the Aviation Color Code to RED and Alert level to WARNING for Bogoslof volcano.

Winds are carrying the cloud from Bogoslof to the southeast, towards Unalaska Island.
(12) Volcanic cloud height: 25,000 ft asl estimated by satellite
(13) Other volcanic cloud information: Cloud moving towards southeast
(14) Remarks: The SIGMET warning message for aviation, issued by the National Weather Service Alaska Aviation Weather Unit, currently is in effect up to 25,000 ft above sea level. Status of the ash cloud forecast can be found at their website at http://aawu.arh.noaa.gov/

See http://www.weather.gov/afc/ for details on ash fall forecasts from the National Weather Service.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jeff Freymueller, Coordinating Scientist, UAFGI
jfreymueller@alaska.edu (907) 322-4085
(16) Next Notice:
2017-02-20 - Bogoslof, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170220/0225Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: ORANGE
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: An explosive eruption began at Bogoslof volcano at 02:08 20 February UTC (17:08 19 February AKST) as indicated in seismic and infrasound data. At this time there have been no satellite images received to indicate size of volcanic plume. The Aviation Color Code remains at ORANGE, but we will continue to monitor data closely and provide updates as necessary.
(12) Volcanic cloud height: None observed yet
(13) Other volcanic cloud information: Not available
(14) Remarks: The National Weather Service Alaska Aviation Weather Unit has issued an eruption SIGMET warning for aviation up to XX,XXX ft above sea level. This may be revised as new information becomes available. Please see the NWS AAWU at http://www.weather.gov/aawu/sigmets for updated information on aviation warning messages.

Winds at the volcano would currently carry an eruption cloud southeast towards Unalaska Island. Please see the National Weather Service for notices regarding ashfall: http://www.weather.gov/afc/
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jeff Freymueller, Coordinating Scientist, UAFGI
jfreymueller@alaska.edu (907) 322-4085
(16) Next Notice:
2017-02-20 - Bogoslof, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170220/0135Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: ORANGE
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: Seismicity as detected on instruments located on nearby islands is elevated and increasing in intensity, suggesting that an explosive eruption is likely imminent. As of yet there is no confirmation of significant ash emissions detected by lightning, infrasound or satellite data.

The Aviation Color Code remains at ORANGE and the Volcano Alert Level remains at WATCH.

AVO is evaluating all data sources and will update this report as more information becomes available.
(12) Volcanic cloud height: Not yet observed
(13) Other volcanic cloud information: Not available
(14) Remarks: Status of any ash clouds can be found at the Alaska Aviation Weather Unit website at http://aawu.arh.noaa.gov/
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jeff Freymueller, Coordinating Scientist, UAFGI
jfreymueller@alaska.edu (907) 322-4085
(16) Next Notice:
2017-02-19 - Bogoslof, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170219/2110Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: ORANGE
(5) Previous Color Code: RED
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: No further ash emissions have occurred at Bogoslof Volcano since the explosion on Saturday 18 February at 4:50 AKST (13:50 UTC) and seismicity remains low. We are therefore lowering the Aviation Color Code to ORANGE and the Alert Level to WATCH. Additional ash-producing eruptions could occur at any time, however, with no detectable precursors.
(12) Volcanic cloud height: Not applicable
(13) Other volcanic cloud information: Not applicable
(14) Remarks:
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jeff Freymueller, Coordinating Scientist, UAFGI
jfreymueller@alaska.edu (907) 322-4085
(16) Next Notice:
2017-02-18 - Bogoslof, Aviation Color Code: RED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170218/1439Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: RED
(5) Previous Color Code: RED
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: An explosive eruption began at Bogoslof volcano at 04:26 AKST (13:26 UTC) as indicated in seismic and lightning data. Preliminary evidence from satellite suggests the cloud is at least as high as 25,000 ft asl. Seismic data suggest that the main ash emissions lasted for several minutes and seismicity is currently low again.

AVO is evaluating all data sources and will update this report as more information becomes available.
(12) Volcanic cloud height: At least 25,000 ft all
(13) Other volcanic cloud information: winds are variable in the area
(14) Remarks: The National Weather Service Alaska Aviation Weather Unit has issued an eruption SIGMET warning for aviation up to 25,000 ft above sea level. This may be revised as new information becomes available. Please see the NWS AAWU at http://www.weather.gov/aawu/sigmets for updated information on aviation warning messages.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jeff Freymueller, Coordinating Scientist, UAFGI
jfreymueller@alaska.edu (907) 322-4085
(16) Next Notice:
2017-02-18 - Bogoslof, Aviation Color Code: RED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170218/0134Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: RED
(5) Previous Color Code: RED
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: Another short-lived explosive eruption occurred today at about 15:46 AKST (00:46 UTC) as detected in seismic and infrasound data. A volcanic cloud is visible in satellite and is as high as 25,000 ft asl. No lightning was associated with this event.

Seismicity as detected on nearby islands is back to low levels, but Bogoslof volcano remains at a heightened state of unrest and in an unpredictable condition. Additional explosions producing high-altitude volcanic clouds could occur at any time. Low-level explosive activity that is below our ability to detect in our data sources may be occurring. These low-level explosions could pose a hazard in the immediate vicinity of the volcano.

The Aviation Color Code remains at RED and the Alert Level remains at WARNING.
(12) Volcanic cloud height: SIGMET to 25,000 ft asl
(13) Other volcanic cloud information: Winds are to the north
(14) Remarks: The SIGMET warning message for aviation, issued by the National Weather Service Alaska Aviation Weather Unit, currently is in effect up to 25,000 ft above sea level. Status of the ash cloud forecast can be found at their website at http://aawu.arh.noaa.gov/

No ash fallout is expected in populated areas as winds are to the north.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jeff Freymueller, Coordinating Scientist, UAFGI
jfreymueller@alaska.edu (907) 322-4085
(16) Next Notice:
2017-02-17 - Bogoslof, Aviation Color Code: RED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170217/1948Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: RED
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: A significant explosive eruption began at Bogoslof volcano at 18:55 UTC (09:55 AKST) today. Pulses of seismicity are continuing. Preliminary satellite data show an ash cloud, and lightning continues to be detected. Thus, AVO is raising the Aviation Color Code to RED and Alert level to WARNING for Bogoslof volcano.

Winds are from the south and will generally carry the ash cloud north over the Bering Sea.

Activity is ongoing and additional explosive events may occur. We will provide more information about the ash cloud as it becomes available.
(12) Volcanic cloud height: SIGMET to 25,000 ft asl
(13) Other volcanic cloud information: Cloud moving generally north
(14) Remarks: The SIGMET warning message for aviation, issued by the National Weather Service Alaska Aviation Weather Unit currently is in effect up to 25,000 ft above sea level. Status of the ash cloud forecast can be found at their website at http://aawu.arh.noaa.gov/

No ash fallout is expected in populated areas as winds are to the north.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jeff Freymueller, Coordinating Scientist, UAFGI
jfreymueller@alaska.edu (907) 322-4085
(16) Next Notice:
2017-02-17 - Bogoslof, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170217/1921Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: ORANGE
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: Seismicity as detected on instruments located on nearby islands has recently increased. Infrasound sensors on Okmok Volcano have also detected airwaves suggesting an explosive eruption has commenced.

The Aviation Color Code remains at ORANGE and the Volcano Alert Level remains at WATCH.

AVO is evaluating all data sources and will update this report as more information becomes available.
(12) Volcanic cloud height: Not observed
(13) Other volcanic cloud information: Not available
(14) Remarks: Status of any ash clouds can be found at the Alaska Aviation Weather Unit website at http://aawu.arh.noaa.gov/
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jeff Freymueller, Coordinating Scientist, UAFGI
jfreymueller@alaska.edu (907) 322-4085
(16) Next Notice:
2017-02-13 - Bogoslof, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170213/1900Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: ORANGE
(5) Previous Color Code: RED
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: Strong seismic activity at Bogoslof this morning from about 16:24 to 17:32 UTC (07:24 to 08:32 AKST) was detected on stations from nearby islands. Similar seismic activity has been associated with explosive eruptions that produced significant ash clouds from the volcano. Thus, AVO raised the Aviation Color Code to RED and Alert level to WARNING for Bogoslof volcano.

However, satellite data through 18:30 UTC (09:30 AKST) show no volcanic cloud visible about the weather cloud tops of about 10,000 ft asl. There were also no lightning strokes detected during this morning's activity. We therefore conclude that, despite the intensity of seismic activity, a significant volcanic cloud was not produced during this event. We are thus lowering the Aviation Color Code to ORANGE and the Alert Level to WATCH.

Ash emissions to lower altitudes, as well as other eruptive activity, likely did occur during this morning's event, and conditions at the volcano remain unstable. Additional explosive activity could occur at any time, with little or no advance warning.
(12) Volcanic cloud height: No cloud above about 10,000 ft asl
(13) Other volcanic cloud information: None available
(14) Remarks: The SIGMET warning message for aviation, issued by the National Weather Service Alaska Aviation Weather Unit, was cancelled earlier this morning. Status of the ash cloud forecast can be found at their website at http://aawu.arh.noaa.gov/

The National Weather Service issued a Marine Weather Statement for the area around Umnak Pass: http://www.weather.gov/afc/
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jessica Larsen, Acting Coordinating Scientist, UAFGI
jflarsen@alaska.edu (907) 322-4085
(16) Next Notice:
2017-02-13 - Bogoslof, Aviation Color Code: RED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170213/1654Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: RED
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: A significant explosive eruption began at Bogoslof volcano at about 16:24 UTC on February 13 (07:24 AKST on February 13) as indicated in seismic data. Although at this time there has been no lightning detected, nor satellite images received to confirm eruptive activity, the intensity of seismicity strongly suggests that significant ash emissions have occurred. Thus, AVO is raising the Aviation Color Code to RED and Alert level to WARNING.

AVO is evaluating all data sources and will update this report as more information becomes available.
(12) Volcanic cloud height: None observed yet.
(13) Other volcanic cloud information: not available
(14) Remarks: Please see the NWS AAWU at http://www.weather.gov/aawu/sigmets for updated information on aviation warning messages.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jessica Larsen, Acting Coordinating Scientist, UAFGI
jflarsen@alaska.edu (907) 322-4085
(16) Next Notice:
2017-02-13 - Bogoslof, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170213/1620Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: ORANGE
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: Seismicity as detected on instruments located on nearby islands is elevated and increasing in intensity, suggesting that an explosive eruption is likely imminent or has commenced. As of yet there is no confirmation of significant ash emissions detected by lightning, infrasound or satellite data.

The Aviation Color Code remains at ORANGE and the Volcano Alert Level remains at WATCH.

AVO is evaluating all data sources and will update this report as more information becomes available.
(12) Volcanic cloud height: Not observed
(13) Other volcanic cloud information: Not available
(14) Remarks: Status of any ash clouds can be found at the Alaska Aviation Weather Unit website at http://aawu.arh.noaa.gov/
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jessica Larsen, Acting Coordinating Scientist, UAFGI
jflarsen@alaska.edu (907) 322-4085
(16) Next Notice:
2017-02-08 - Takawangha, Aviation Color Code: GREEN (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170208/2013Z)
(3) Volcano: Takawangha (VNUM #311090)
(4) Current Color Code: GREEN
(5) Previous Color Code: YELLOW
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 51 deg 52 min W 178 deg 1 min
(9) Area: Aleutians
(10) Summit Elevation: 4754 ft (1449 m)
(11) Volcanic Activity Summary: The energetic earthquake swarm on Tanaga Island that began on January 23, 2017, has declined significantly and seismicity is near background levels. Therefore, AVO is lowering the Aviation Color Code to GREEN and Alert Level to NORMAL for Takawangha volcano.
(12) Volcanic cloud height: Not applicable
(13) Other volcanic cloud information: Not applicable
(14) Remarks: Takawangha is a remote, 1,449 m (4,754 ft)-high stratovolcano located on the northeast portion of Tanaga Island, roughly 95 km (59 miles) west of Adak in the Andreanof Islands. Takawangha's summit is mostly ice-covered, except for four young craters that have erupted ash and lava flows in the last few thousand years. Parts of Takawangha's edifice are hydrothermally altered and may be unstable, possibly leading to localized debris avalanches from its flanks. Takawangha lies across a saddle from historically active Tanaga volcano to the west. No historical eruptions are known from Takawangha; however, field work shows that recent eruptions have occurred and it is possible that historic eruptions attributed to Tanaga may instead have come from Takawangha.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jessica Larsen, Acting Coordinating Scientist, UAFGI
jflarsen@alaska.edu (907) 322-4085
(16) Next Notice:
2017-02-04 - Bogoslof, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170204/0224Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: ORANGE
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2017/A86
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: Seismic tremor began at Bogoslof at 1:41 UTC on February 4 (16:42, February 3 AKST) and is continuing. No ash cloud has been detected as of yet in satellite data, but volcanic ash emissions are likely occurring. Winds are towards the north over the Bering Sea. We are evaluating the magnitude of this eruptive episode. The Aviation Color Code remains at ORANGE and the Volcano Alert Level remains at WATCH at present.

The National Weather Service Alaska Aviation Weather Unit has issued an eruption SIGMET warning for aviation up to 20,000 ft above sea level. This will be revised as new information becomes available. Please see the NWS AAWU at http://www.weather.gov/aawu/sigmets for updated information on aviation warning messages.

(12) Volcanic cloud height: none detected yet
(13) Other volcanic cloud information: N/A
(14) Remarks:
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jeff Freymueller, Coordinating Scientist, UAFGI
jfreymueller@alaska.edu (907) 322-4085
(16) Next Notice:
2017-02-03 - Cleveland, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170203/2305Z)
(3) Volcano: Cleveland (VNUM #311240)
(4) Current Color Code: ORANGE
(5) Previous Color Code: YELLOW
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2017/A87
(8) Volcano Location: N 52 deg 49 min W 169 deg 56 min
(9) Area: Aleutians
(10) Summit Elevation: 5676 ft (1730 m)
(11) Volcanic Activity Summary: Recent satellite observations indicate that a new lava dome has been extruded and is partially filling the summit crater at Cleveland volcano. The new dome is about 70 m (230 feet) in diameter and is similar in size to previous lava domes that have developed on the floor of the crater. When lava domes have developed within the summit crater, explosive activity has sometimes followed. The extrusion of the lava dome and the increased potential for explosive activity prompts AVO to change the Aviation Color Code to ORANGE and the Volcano Alert Level to WATCH.

Cleveland volcano is not monitored with a real-time seismic network and this inhibits AVO's ability to detect unrest that may lead to an explosive eruption. Rapid detection of an ash-producing eruption may be possible using a combination of satellite, infrasound, lightning data and local observations. AVO is monitoring the unrest at Cleveland volcano as closely as possible and will release additional information if or when it becomes available.
(12) Volcanic cloud height: No volcanic clouds observed.
(13) Other volcanic cloud information: No cloud observed.
(14) Remarks: Cleveland volcano forms the western portion of Chuginadak Island, a remote and uninhabited island in the east central Aleutians. The volcano is located about 75 km (45 mi) west of the community of Nikolski, and 1500 km (940 mi) southwest of Anchorage. The most recent significant period of eruption began in February, 2001 and produced 3 explosive events that generated ash clouds as high as 39,000 ft above sea level. The 2001 eruption also produced a lava flow and hot avalanche that reached the sea. Since then, Cleveland has been intermittently active producing small lava flows, often followed by explosions that generate small ash clouds generally below 20,000 ft above sea level. These explosions also launch debris onto the slopes of the cone producing hot pyroclastic avalanches and lahars that sometimes reach the coastline.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jeff Freymueller, Coordinating Scientist, UAFGI
jfreymueller@alaska.edu (907) 322-4085
(16) Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at
http://www.avo.alaska.edu
2017-02-02 - Pavlof, Aviation Color Code: GREEN (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170202/2051Z)
(3) Volcano: Pavlof (VNUM #312030)
(4) Current Color Code: GREEN
(5) Previous Color Code: YELLOW
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2017/A85
(8) Volcano Location: N 55 deg 25 min W 161 deg 53 min
(9) Area: Alaska Peninsula
(10) Summit Elevation: 8261 ft (2518 m)
(11) Volcanic Activity Summary: The level of unrest at Pavlof has gradually decreased to background levels over the past several months. Therefore we are lowering the Aviation Color Code to GREEN and the Alert Level to NORMAL. No activity has been observed in satellite data since January 8 when weakly elevated surface temperatures were detected. Seismic levels are considered to be at background levels. Occasional, small, low frequency events continue to be seen in seismic data and are consistent with an open degassing system. Low-level steam and gas plumes from the summit are likely to be seen when meteorological conditions are favorable.
(12) Volcanic cloud height: None
(13) Other volcanic cloud information: None
(14) Remarks: Pavlof Volcano is a snow- and ice-covered stratovolcano located on the southwestern end of the Alaska Peninsula about 953 km (592 mi) southwest of Anchorage. The volcano is about 7 km (4.4 mi) in diameter and has active vents on the north and east sides close to the summit. With over 40 historic eruptions, it is one of the most consistently active volcanoes in the Aleutian arc. Eruptive activity is generally characterized by sporadic Strombolian lava fountaining continuing for a several-month period. Ash plumes as high as 49,000 ft ASL have been generated by past eruptions of Pavlof, and during the March 2016 eruption, ash plumes as high as 40,000 feet above sea level were generated and the ash was tracked in satellite data as distant as eastern Canada. The nearest community, Cold Bay, is located 60 km (37 miles) to the southwest of Pavlof.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jeff Freymueller, Coordinating Scientist, UAFGI
jfreymueller@alaska.edu (907) 322-4085
(16) Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at
http://www.avo.alaska.edu
2017-02-01 - Bogoslof, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170201/2006Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: ORANGE
(5) Previous Color Code: RED
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2017/A84
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: No new volcanic emissions have been detected from Bogoslof Volcano since the activity that began at 5:20 UTC, January 31 (20:20 AKST, January 30). No detectable activity has been observed in recent seismic, infrasound or lightning data. AVO is reducing the Aviation Color code to ORANGE and the Alert Level to WATCH. High winds in the region are being seen on seismic and infrasound stations making it difficult to detect smaller signals from Bogoslof. Significant ash-producing explosions could occur at any time, with no detectable precursors. Low-level activity below our detection limit is possible and may present a hazard in the immediate vicinity of the island.

(12) Volcanic cloud height: N/A
(13) Other volcanic cloud information: N/A
(14) Remarks:
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jeff Freymueller, Coordinating Scientist, UAFGI
jfreymueller@alaska.edu (907) 322-4085
(16) Next Notice:
2017-01-31 - Bogoslof, Aviation Color Code: RED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170131/0725Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: RED
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2017/A82
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: Bursts of explosive activity that began at 5:20 UTC are continuing and intensifying. More than 10 short-duration explosions have been detected in seismic, infrasound and lightning data. Several discrete volcanic clouds have been observed in satellite data. The intensity of these events are increasing, as is the altitude of the volcanic clouds. Thus, AVO is raising the Aviation Color Code to RED and Alert level to Warning for Bogoslof volcano.

Satellite data through 07:00 UTC shows a volcanic cloud with an estimated altitude of 20,000 ft asl moving towards the east. Activity is ongoing and additional explosive events may occur. A status update will be issued as conditions warrant.
(12) Volcanic cloud height: 20,000
(13) Other volcanic cloud information: Moving towards the east
(14) Remarks: Please reference the National Weather Service Alaska Aviation Weather Unit for current information on the volcanic cloud movement. http://aawu.arh.noaa.gov/
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jeff Freymueller, Coordinating Scientist, UAFGI
jfreymueller@alaska.edu (907) 322-4085
(16) Next Notice:
2017-01-31 - Bogoslof, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170131/0617Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: ORANGE
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2017/A81
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: Several short bursts of activity have been detected in seismic data beginning at 5:20 and at 6:08 UTC. An infrasound signal accompanied the first event indicating an explosive emission from Bogoslof. An eruption cloud has been observed in satellite data at 5:30 UTC to an altitude of 20,000 ft above sea level by the National Weather Service. We are evaluating the cloud height as new data comes in and will update if needed.

The Aviation Color Code remains at ORANGE and the Volcano Alert Level at WATCH.

(12) Volcanic cloud height: 20,000
(13) Other volcanic cloud information: initial estimate
(14) Remarks: Please reference the National Weather Service Alaska Aviation Weather Unit for current information on the volcanic cloud movement. http://aawu.arh.noaa.gov/
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jeff Freymueller, Coordinating Scientist, UAFGI
jfreymueller@alaska.edu (907) 322-4085
(16) Next Notice:
2017-01-28 - Bogoslof, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170128/0043Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: ORANGE
(5) Previous Color Code: RED
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2017/A53
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: No further ash emissions have occurred at Bogoslof volcano since the explosion today at 08:24 AKST (17:24 UTC). No detectable activity observed in seismic, infrasound or lightning data. We are therefore lowering the Aviation Color Code to ORANGE and the Alert Level to WATCH. Significant ash-producing explosions could occur at any time, with no detectable precursors. Low-level activity below our detection limit is possible and may present a hazard in the immediate vicinity of the island.

The volcanic cloud from the eruption this morning has dissipated and the SIGMET aviation warning message that is issued by the National Weather Service expired today at 11:15 AKST (2215 UTC)
(12) Volcanic cloud height: none observed
(13) Other volcanic cloud information: n/a
(14) Remarks:
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jessica Larsen, Acting Coordinating Scientist, UAF
jflarsen@alaska.edu (907) 322-4085
(16) Next Notice:
2017-01-27 - Bogoslof, Aviation Color Code: RED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170127/1831Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: RED
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2017/A27
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: Lightning and seismicity increase indicate a significant explosive eruption began at 08:24 AKST (17:24 UTC). We are thus raising the color code to RED and alert level to WARNING.

Satellite data suggests volcanic cloud may be as high as 25,000 ft asl. The current eruption SIGMET issued by the National Weather Service is up to 30,000 ft asl, but may be updated. We are actively evaluating data sources and will provide an update as necessary.


(12) Volcanic cloud height: 25,000 ft asl from satellite data
(13) Other volcanic cloud information: SIGMET currently to 30,000 ft asl
(14) Remarks: Please refer to the NWS Alaska Aviation Weather unit for updated information on the volcanic cloud forecast.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jessica Larsen, Acting Coordinating Scientist, UAF
jflarsen@alaska.edu (907) 322-4085
(16) Next Notice:
2017-01-27 - Bogoslof, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170127/1737Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: ORANGE
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2017/A46
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: An increase in seismicity at Bogoslof began at 7:47 AKST (16:47 UTC) suggests that an explosive event likely underway or imminent. As of yet, there are no additional indications of eruptive activity in satellite, lightning or infrasound data.

At present, the Aviation Color Code remains at ORANGE and the Alert Level at Watch.

(12) Volcanic cloud height: none observed yet
(13) Other volcanic cloud information: n/a
(14) Remarks:
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jessica Larsen, Acting Coordinating Scientist, UAF
jflarsen@alaska.edu (907) 322-4085
(16) Next Notice:
2017-01-27 - Bogoslof, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170127/0250Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: ORANGE
(5) Previous Color Code: RED
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2017/A44
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: No further ash emissions have occurred at Bogoslof Volcano since the explosion that began today at 06:50 AKST (15:50 UTC). The volcanic ash cloud from that explosion has dissipated and the SIGMET warning for aviation (issued by the National Weather Service) was cancelled today at 13:36 AKST (22:36 UTC). No detectable activity observed in seismic, infrasound or lightning data. We are therefore lowering the Aviation Color Code to ORANGE and the Alert Level to WATCH. Additional ash-producing eruptions could occur at any time, however, with no detectable precursors.

(12) Volcanic cloud height: none observed
(13) Other volcanic cloud information: n/a
(14) Remarks:
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jessica Larsen, Acting Coordinating Scientist, UAF
jflarsen@alaska.edu (907) 322-4085
(16) Next Notice:
2017-01-26 - Bogoslof, Aviation Color Code: RED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170126/1616Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: RED
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2017/A28
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: Lightning and seismicity increase indicate an explosive eruption began at 06:50 AKST (15:50 UTC). A larger burst of seismicity occurred at 07:06 AKST (16:06 UTC). We do not yet have information on volcanic cloud height, but comparison to seismicity from previous events suggests that this event may be similarly energetic. We are thus raising the color code to RED and alert level to WARNING. We are still evaluating data and will provide an update as necessary.

Lower level winds (below 10,000 ft asl) are currently to the southeast and to the northeast at higher altitudes.

(12) Volcanic cloud height: none observed
(13) Other volcanic cloud information: n/a
(14) Remarks: Status of the ash cloud can be found at the Alaska Aviation Weather Unit website at http://aawu.arh.noaa.gov/
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jessica Larsen, Acting Coordinating Scientist, UAF
jflarsen@alaska.edu (907) 322-4085
(16) Next Notice:
2017-01-26 - Bogoslof, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170126/1117Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: ORANGE
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2017/A78
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: An increase in seismicity at about 01:34 AKST (10:24 UTC), as detected on neighboring islands, suggests that an explosive eruption may be imminent. We have detected no lightning nor seen any activity in recent satellite images. We will provide more information as it becomes available.

(12) Volcanic cloud height: none observed
(13) Other volcanic cloud information: n/a
(14) Remarks:
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jessica Larsen, Acting Coordinating Scientist, UAF
jflarsen@alaska.edu (907) 322-4085
(16) Next Notice:
2017-01-25 - Bogoslof, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170125/0158Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: ORANGE
(5) Previous Color Code: RED
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2017/A72
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: No further ash emissions have occurred at Bogoslof Volcano since the explosion today at 04:53 AKST (13:53 UTC). No detectable activity observed in seismic, infrasound or lightning data. We are therefore lowering the Aviation Color Code to ORANGE and the Alert Level to WATCH. Additional ash-producing eruptions could occur at any time, however, with no detectable precursors.

(12) Volcanic cloud height: none observed
(13) Other volcanic cloud information: n/a
(14) Remarks: The volcanic cloud from the eruption this morning has dissipated and the SIGMET aviation warning message that is issued by the National Weather Service expired today at 11:06 AKST (2206 UC)
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jeff Freymueller, Coordinating Scientist, UAFGI
jfreymueller@alaska.edu (907) 322-4085
(16) Next Notice:
2017-01-24 - Takawangha, Aviation Color Code: YELLOW (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170124/1846Z)
(3) Volcano: Takawangha (VNUM #311090)
(4) Current Color Code: YELLOW
(5) Previous Color Code:
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2017/A71
(8) Volcano Location: N 51 deg 52 min W 178 deg 1 min
(9) Area: Aleutians
(10) Summit Elevation: 4754 ft (1449 m)
(11) Volcanic Activity Summary: An energetic earthquake swarm on Tanaga Island started yesterday, January 23, and is continuing. The earthquakes locate 6 to 7 km ESE of Takawangha Volcano. This activity may be due to brittle failure in the surrounding rock caused by magma movement. AVO is therefore raising the Aviation Color Code to Yellow and Alert Level to Advisory for Takawangha Volcano. No eruptive activity has been detected in satellite data.
(12) Volcanic cloud height: Not applicable
(13) Other volcanic cloud information: Not applicable
(14) Remarks: Takawangha is a remote, 1,449 m (4,754 ft)-high stratovolcano located on the northeast portion of Tanaga Island, roughly 95 km (59 miles) west of Adak in the Andreanof Islands. Takawangha's summit is mostly ice-covered, except for four young craters that have erupted ash and lava flows in the last few thousand years. Parts of Takawangha's edifice are hydrothermally altered and may be unstable, possibly leading to localized debris avalanches from its flanks. Takawangha lies across a saddle from historically active Tanaga volcano to the west. No historical eruptions are known from Takawangha; however, field work shows that recent eruptions have occurred and it is possible that historic eruptions attributed to Tanaga may instead have come from Takawangha.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jeff Freymueller, Coordinating Scientist, UAFGI
jfreymueller@alaska.edu (907) 322-4085
(16) Next Notice:
2017-01-24 - Bogoslof, Aviation Color Code: RED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170124/1415Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: RED
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2017/A69
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: Following a period of increasing seismicity, an explosive eruption started at 04:53 AKST (13:53 UTC) this morning as shown in seismic data and by lightning detection. We have not yet observed a volcanic cloud in satellite, but based on recent events with similar seismicity and lightning, we are raising the Aviation Color Code to RED and Alert Level to Warning.
(12) Volcanic cloud height: not yet observed
(13) Other volcanic cloud information: winds to the east
(14) Remarks: Status of the ash cloud can be found at the Alaska Aviation Weather Unit website at http://aawu.arh.noaa.gov/
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jeff Freymueller, Coordinating Scientist, UAFGI
jfreymueller@alaska.edu (907) 322-4085
(16) Next Notice:
2017-01-23 - Bogoslof, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170123/2221Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: ORANGE
(5) Previous Color Code: RED
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2017/A65
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: No further ash emissions have occurred at Bogoslof Volcano since the explosion on Sunday, 22 January 2017 at 14:09 AKST (23:09 UTC). Seismic data flow, which had been interrupted by severe weather, has been restored. Seismicity remains low. We are therefore lowering the Aviation Color Code to ORANGE and the Alert Level to WATCH. Additional ash-producing eruptions could occur at any time, however, with no detectable precursors.
(12) Volcanic cloud height: none observed
(13) Other volcanic cloud information: n/a
(14) Remarks:
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jeff Freymueller, Coordinating Scientist, UAFGI
jfreymueller@alaska.edu (907) 322-4085
(16) Next Notice:
2017-01-22 - Bogoslof, Aviation Color Code: RED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170122/2349Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: RED
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2017/A64
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: The eruption today around 14:09 AKST (23:09 UTC), first detected by lightning, has produced a volcanic cloud seen in satellite images moving north of Bogoslof and reaching as high as 30,000 ft asl. We are raising the Aviation Color Code to RED and the Volcano Alert Level to WARNING.

High winds due to a storm in the area are hindering our ability to detect the eruption in seismic data.
(12) Volcanic cloud height: 30,000 ft asl
(13) Other volcanic cloud information: north of volcano
(14) Remarks: Status of the ash cloud can be found at the Alaska Aviation Weather Unit website at http://aawu.arh.noaa.gov/
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jeff Freymueller, Coordinating Scientist, UAFGI
jfreymueller@alaska.edu (907) 322-4085
(16) Next Notice:
2017-01-22 - Bogoslof, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170122/2331Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: ORANGE
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2017/A62
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: Several lightning strikes north of Bogoslof suggest that an eruption occurred around 14:09 AKST (23:09 UTC). High winds due to a storm in the area are hindering our ability to detect the eruption in seismic data. No volcanic cloud visible in satellite data at this time. We will put out more information as it becomes available.

AVO has no ground-based volcano monitoring equipment on Bogoslof volcano. We continue to monitor satellite images, data from distant seismic and infrasound instruments, and information from the Worldwide Lightning Location Network for indications of significant activity.
(12) Volcanic cloud height: not available
(13) Other volcanic cloud information: not available
(14) Remarks: Status of the ash cloud can be found at the Alaska Aviation Weather Unit website at http://aawu.arh.noaa.gov/
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jeff Freymueller, Coordinating Scientist, UAFGI
jfreymueller@alaska.edu (907) 322-4085
(16) Next Notice:
2017-01-21 - Bogoslof, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170121/2141Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: ORANGE
(5) Previous Color Code: RED
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2017/A52
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: No further ash emissions have occurred at Bogoslof Volcano since the explosion on Friday, 20 January at 13:17 AKST (22:17 UTC) and seismicity remains low. We are therefore lowering the Aviation Color Code to ORANGE and the Alert Level to WATCH. Additional ash-producing eruptions could occur at any time, however, with no detectable precursors.
(12) Volcanic cloud height: Not applicable
(13) Other volcanic cloud information: Not applicable
(14) Remarks:
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jeff Freymueller, Coordinating Scientist, UAFGI
jfreymueller@alaska.edu (907) 322-4085
(16) Next Notice:
2017-01-20 - Bogoslof, Aviation Color Code: RED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170120/2230Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: RED
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2017/A47
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: Explosive eruption of Bogoslof confirmed, starting at approximately 13:17 AKST (22:17 UTC) based on seismic data and lightning detected from the World Wide Lightning Location Network. A volcanic plume is not yet visible in satellite data. Winds are currently to the southeast. More information to follow.

We are raising the Aviation Color Code to RED and the Alert Level to WARNING.

AVO has no ground-based volcano monitoring equipment on Bogoslof volcano. We continue to monitor satellite images, data from distant seismic and infrasound instruments, and information from the Worldwide Lightning Location Network for indications of significant activity.
(12) Volcanic cloud height: not available
(13) Other volcanic cloud information: not available
(14) Remarks: Status of the ash cloud can be found at the Alaska Aviation Weather Unit website at http://aawu.arh.noaa.gov/
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jeff Freymueller, Coordinating Scientist, UAFGI
jfreymueller@alaska.edu (907) 322-4085
(16) Next Notice:
2017-01-20 - Bogoslof, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170120/2210Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: ORANGE
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2017/A45
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: An increase in seismicity starting at about 13:00 AKST (22:00 UTC) suggests an explosive eruption of Bogoslof may be imminent. We will issue more information as it becomes available.
(12) Volcanic cloud height: not observed
(13) Other volcanic cloud information: not available
(14) Remarks: Status of the ash cloud can be found at the Alaska Aviation Weather Unit website at http://aawu.arh.noaa.gov/
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jeff Freymueller, Coordinating Scientist, UAFGI
jfreymueller@alaska.edu (907) 322-4085
(16) Next Notice:
2017-01-19 - Bogoslof, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170119/2148Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: ORANGE
(5) Previous Color Code: RED
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2017/A40
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: No further ash emissions have occurred at Bogoslof Volcano since the explosion on Wednesday, 18 January at 13:20 AKST (22:20 UTC) and seismicity remains low. We are therefore lowering the Aviation Color Code to ORANGE and the Alert Level to WATCH. Additional ash-producing eruptions could occur at any time, however, with no detectable precursors.
(12) Volcanic cloud height: Not applicable
(13) Other volcanic cloud information: Not applicable
(14) Remarks:
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jeff Freymueller, Coordinating Scientist, UAFGI
jfreymueller@alaska.edu (907) 322-4085
(16) Next Notice:
2017-01-18 - Bogoslof, Aviation Color Code: RED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170118/2259Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: RED
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2017/A35
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: Explosive eruption of Bogoslof confirmed, starting at approximately 13:20 AKST (22:20 UTC). Ash cloud is at least as high as 31,000 ft asl as noted in pilot reports. Volcanic cloud observed in satellite images generally moving to northeast.

We are raising the Aviation Color Code to RED and the Alert Level to WARNING.

AVO has no ground-based volcano monitoring equipment on Bogoslof volcano. We continue to monitor satellite images, data from distant seismic and infrasound instruments, and information from the Worldwide Lightning Location Network for indications of significant activity.
(12) Volcanic cloud height: at least 31,000 ft asl
(13) Other volcanic cloud information: not available
(14) Remarks: Status of the ash cloud can be found at the Alaska Aviation Weather Unit website at http://aawu.arh.noaa.gov/
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jeff Freymueller, Coordinating Scientist, UAFGI
jfreymueller@alaska.edu (907) 322-4085
(16) Next Notice:
2017-01-18 - Bogoslof, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170118/2215Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: ORANGE
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2017/A33
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: An increase in seismicity starting at about 13:00 AKST (22:00 UTC) suggests an explosive eruption of Bogoslof may be imminent. We will issue more information as it becomes available.
(12) Volcanic cloud height: not observed
(13) Other volcanic cloud information: not available
(14) Remarks: Status of the ash cloud can be found at the Alaska Aviation Weather Unit website at http://aawu.arh.noaa.gov/
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jeff Freymueller, Coordinating Scientist, UAFGI
jfreymueller@alaska.edu (907) 322-4085
(16) Next Notice:
2017-01-17 - Bogoslof, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170117/1756Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: ORANGE
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2017/A22
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: Increased seismic activity over the past several hours indicates that minor explosive activity is occurring at Bogoslof. The level of activity is variable, with the most energetic events observed around 1500 UTC and 1640 UTC (4:00 and 7:40 am AKST). Minor emissions of steam and minor amounts of volcanic ash observed in satellite data around 1500 and 1730 UTC. These events were too small to generate detectable lightning or infrasound (pressure) signals. The National Weather Service has estimated a maximum altitude for these small clouds at 15,000 ft above sea level. Satellite data showed that they dissipated quickly. The volcano remains restless and additional explosive events could occur with little warning.
(12) Volcanic cloud height: 15,000 ft asl (maximum)
(13) Other volcanic cloud information: Minor emissions visible in satellite data
(14) Remarks: Status of the ash cloud can be found at the Alaska Aviation Weather Unit website at http://aawu.arh.noaa.gov/
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jeff Freymueller, Coordinating Scientist, UAFGI
jfreymueller@alaska.edu (907) 322-4085
(16) Next Notice:
2017-01-15 - Bogoslof, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170115/0650Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: ORANGE
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2017/A19
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: Seismicity increased starting at about 21:26 AKST (06:26 Jan 15 UTC) suggesting an explosive eruption of Bogoslof is likely occurring. We will issue more information as it becomes available.
(12) Volcanic cloud height: not observed
(13) Other volcanic cloud information: not available
(14) Remarks: Status of the ash cloud can be found at the Alaska Aviation Weather Unit website at http://aawu.arh.noaa.gov/
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Janet Schaefer, Acting Coordinating Scientist, DGGS
janet.schaefer@alaska.gov (907) 322-4085
(16) Next Notice:
2017-01-12 - Bogoslof, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170112/2235Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: ORANGE
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2017/A18
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: A second explosive event has been detected at Bogoslof volcano. An abrupt increase in seismicity began at about 21:35 UTC (12:35 AKST). Both events have been observed by pilots. The first event at 20:23 UTC produced an eruption cloud to 18,000 ft asl. The estimated height of the second event from 21:35 UTC was 14,500 ft asl. Neither eruption cloud has been visible yet in subsequent satellite data. The altitude of the meteorological cloud deck is variable from about 10,000 ft to 12,000 ft. Additional ash-producing eruptions may occur at any time with limited precursory unrest and little warning. AVO is monitoring the volcano closely and will provide additional information if and when it becomes available.
(12) Volcanic cloud height: Two events: First 18,000 ft. Second 14,500 ft asl
(13) Other volcanic cloud information: Height from pilot reports.
(14) Remarks:
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Janet Schaefer, Acting Coordinating Scientist, DGGS
janet.schaefer@alaska.gov (907) 322-4085
(16) Next Notice:
2017-01-12 - Bogoslof, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170112/2048Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: ORANGE
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2017/A17
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: The level of seismic activity at Bogoslof volcano increased abruptly at about 20:23 (11:23 AKST) and persisted at a high level until about 20:29 UTC (11:29 AKST). Previous increases in seismicity similar to this one have resulted in volcanic plumes as high as about 30,000 feet asl. Nothing yet has been observed in satellite data and lightning has not been detected but a plume likely has been generated. It remains possible for additional ash-producing eruptions to occur at any time with limited precursory unrest and little warning. AVO is monitoring the volcano closely and will provide additional information if and when it becomes available.
(12) Volcanic cloud height: Not observed
(13) Other volcanic cloud information: Not available
(14) Remarks:
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Janet Schaefer, Acting Coordinating Scientist, DGGS
janet.schaefer@alaska.gov (907) 322-4085
(16) Next Notice:
2017-01-10 - Bogoslof, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170110/1802Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: ORANGE
(5) Previous Color Code: RED
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2017/A16
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: The level of seismic activity at Bogoslof volcano has declined and no further volcanic emissions have occurred since the two strong eruptive pulses on January 8, 2017 at about 22:33 and 22:56 AKST (07:33 and 07:56 Jan 9 UTC). We are therefore lowering the Aviation Color Code to ORANGE and the Alert Level to WATCH. It remains possible for additional ash-producing eruptions to occur at any time with limited precursory unrest and little warning.
(12) Volcanic cloud height: Not observed
(13) Other volcanic cloud information: Not available
(14) Remarks:
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Janet Schaefer, Acting Coordinating Scientist, DGGS
janet.schaefer@alaska.gov (907) 322-4085
(16) Next Notice:
2017-01-09 - Bogoslof, Aviation Color Code: RED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170109/0754Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: RED
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2017/A14
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: Explosive eruption of Bogoslof occurred starting around 22:23 AKST (07:23 Jan 9 UTC) as detected in seismic and infrasound data, with the strongest signal at about 22:31 AKST (07:31 Jan 9 UTC). Seismic signal declined around 22:38 AKST (07:38 Jan 9 UTC) but is still above background. We do not yet have any satellite images of a cloud but seismicity suggests an event at least as large as others in the recent sequence. We are raising Aviation Color Code to RED and Volcano Alert Level to WARNING.

Winds are currently out of the southeast.
(12) Volcanic cloud height: Not observed
(13) Other volcanic cloud information: Not available
(14) Remarks: Status of the ash cloud can be found at the Alaska Aviation Weather Unit website at http://aawu.arh.noaa.gov/
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Janet Schaefer, Acting Coordinating Scientist, DGGS
janet.schaefer@alaska.gov (907) 322-4085
(16) Next Notice:
2017-01-09 - Bogoslof, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170109/0732Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: ORANGE
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2017/A13
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: Seismicity as detected on nearby islands is elevated and increasing in intensity, suggesting that an explosive eruption is likely imminent or has commenced. No lightning has been detected nor any cloud visible in satellite. We will provide more information as it becomes available.
(12) Volcanic cloud height: Not observed
(13) Other volcanic cloud information: Not available
(14) Remarks: Status of any ash clouds can be found at the Alaska Aviation Weather Unit website at http://aawu.arh.noaa.gov/
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Janet Schaefer, Acting Coordinating Scientist, DGGS
janet.schaefer@alaska.gov (907) 322-4085
(16) Next Notice:
2017-01-06 - Bogoslof, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170106/2051Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: ORANGE
(5) Previous Color Code: RED
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2017/A12
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: No further ash emissions have occurred at Bogoslof Volcano since the explosion on Thursday, January 5 at 13:24 AKST (22:24 UTC). We are therefore lowering the Aviation Color Code to ORANGE and the Alert Level to WATCH. Additional ash-producing eruptions could occur at any time, however, with no detectable precursors.
(12) Volcanic cloud height: Not applicable
(13) Other volcanic cloud information: Not applicable
(14) Remarks:
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Janet Schaefer, Acting Coordinating Scientist, DGGS
janet.schaefer@alaska.gov (907) 322-4085
(16) Next Notice:
2017-01-05 - Bogoslof, Aviation Color Code: RED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170105/2242Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: RED
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2017/A11
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: AVO has just detected an escalation in seismicty beginning at about 13:24 January 5 AKST (22:24 UTC) from Bogoslof volcano. This activity is accompanied by lightning strikes detected by the World Wide Lightning Detection Network indicating that a significant explosion has occurred. Based on the intensity of these signals AVO is raising the Aviation Color Code to RED and Alert Level to WARNING. More details will be provided as they become available.
(12) Volcanic cloud height: Not yet available
(13) Other volcanic cloud information: Not yet available
(14) Remarks: Status of the ash cloud can be found at the Alaska Aviation Weather Unit website at http://aawu.arh.noaa.gov/
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Janet Schaefer, Acting Coordinating Scientist, DGGS
janet.schaefer@alaska.gov (907) 322-4085
(16) Next Notice:
2017-01-05 - Bogoslof, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170105/2047Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: ORANGE
(5) Previous Color Code: RED
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2017/A10
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: No further ash emissions have occurred at Bogoslof since Tuesday, January 3 at 21:18 AKST (6:18 UTC January 4). AVO is therefore lowering the Aviation Color Code to ORANGE and Alert Level to WATCH. Additional ash-producing eruptions could occur at any time, however, with no detectable precursors.
(12) Volcanic cloud height: NA
(13) Other volcanic cloud information: NA
(14) Remarks: Status of the ash cloud can be found at the Alaska Aviation Weather Unit website at http://aawu.arh.noaa.gov/
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Janet Schaefer, Acting Coordinating Scientist, DGGS
janet.schaefer@alaska.gov (907) 322-4085
(16) Next Notice:
2017-01-04 - Bogoslof, Aviation Color Code: RED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170104/0704Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: RED
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2017/A8
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: Seismic data from nearby islands detected a volcanic signal from Bogoslof volcano starting at 21:18 AKST today (6:18 UTC Jan 4) lasting ~5 minutes and a series of lightning strikes were identified by the World Wide Lightning Location Network. An eruption cloud as high as 33,000 ft has been detected in satellite data. AVO is therefore raising the Aviation Color Code for Bogoslof to RED and Volcano Alert Level to Warning.
(12) Volcanic cloud height: As high as 33,000 asl
(13) Other volcanic cloud information: moving north
(14) Remarks: Status of the ash cloud can be found at the Alaska Aviation Weather Unit website at http://aawu.arh.noaa.gov/
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Janet Schaefer, Acting Coordinating Scientist, DGGS
janet.schaefer@alaska.gov (907) 322-4085
(16) Next Notice:
2017-01-02 - Bogoslof, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170102/2348Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: ORANGE
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: Seismic data from nearby islands detected a volcanic signal from Bogoslof volcano starting at 13:53 AKST (22:53 UTC) today lasting ~10 minutes. Infrasound (pressure) sensors near Cleveland volcano also detected a signal from Bogoslof, indicating an ash-producing eruption likely occurred. No lightning strikes were identified by the World Wide Lightning Location Network, and no ash-plume above the regional cloud deck (18,000 ft asl) was identified in satellite data over the past 40 minutes. The short duration of seismicity and lack of evidence for ash above the clouds in satellite data suggest this was likely a relatively minor explosion. The current Aviation Color Code remains ORANGE and Volcano Alert Level WATCH.
(12) Volcanic cloud height: Less than 18000 ft asl
(13) Other volcanic cloud information: none
(14) Remarks: Status of the ash cloud can be found at the Alaska Aviation Weather Unit website at http://aawu.arh.noaa.gov/
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Janet Schaefer, Acting Coordinating Scientist, DGGS
janet.schaefer@alaska.gov (907) 322-4085
(16) Next Notice:
2017-01-01 - Bogoslof, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20170101/1932Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: ORANGE
(5) Previous Color Code: RED
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2017/A1
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: No further ash emissions have occurred at Bogoslof since Friday, December 30 at 22:30 AKST (07:30 UTC Dec 31). We are thus lowering the Aviation Color Code to ORANGE and the Alert Level to WATCH. Additional ash-producing eruptions could occur at any time, however, with no detectable precursors.

AVO has no ground-based volcano monitoring equipment on Bogoslof volcano. We continue to monitor satellite images, information from the Worldwide Lightning Location Network pertaining to volcanic-cloud lightning, and data from seismic and infrasound instruments on other islands for indications of volcanic activity. At present, these observations should allow timely detection of additional explosive events.
(12) Volcanic cloud height: n/a
(13) Other volcanic cloud information: None detected since December 30
(14) Remarks:
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Janet Schaefer, Acting Coordinating Scientist, DGGS
janet.schaefer@alaska.gov (907) 322-4085
(16) Next Notice:
2016-12-30 - Bogoslof, Aviation Color Code: RED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20161230/1010Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: RED
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: An ash-producing eruption started at 23:45 Dec 29 AKST (08:45 Dec 30 UTC) and is continuing as recorded by seismic data on nearby islands and as seen in recent satellite images. Cloud-top temperatures from satellite suggest a cloud height of around 20,000 ft asl. Regional winds are from the southwest. We are raising the Aviation Color Code to RED and the Alert Level to WARNING.

AVO has no ground-based volcano monitoring equipment on Bogoslof volcano. We continue to monitor satellite images, information from the Worldwide Lightning Location Network pertaining to volcanic-cloud lightning, and data from seismic and infrasound instruments on other islands for indications of volcanic activity. At present, these observations should allow timely detection of additional explosive events.
(12) Volcanic cloud height: Likely around 20,000 ft asl from satellite
(13) Other volcanic cloud information: Winds are from southwest
(14) Remarks: Status of the ash cloud can be found at the Alaska Aviation Weather Unit website at http://aawu.arh.noaa.gov/
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Pavel Izbekov, Acting Coordinating Scientist, UAFGI
pavel@gi.alaska.edu (907) 322-4085
(16) Next Notice:
2016-12-30 - Bogoslof, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20161230/0843Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: ORANGE
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: Seismic data from nearby islands detected an increase in discrete volcanic seismicity from Bogoslof volcano starting at 19:00 Dec 29 AKST (04:00 UTC Dec 30) today. The activity progressed, merging into a continuous tremor sequence indicative of a possible ash-producing eruption, as was seen with the eruption on December 21. Nothing has yet been observed in satellite data and no lightning strikes associated with an ash cloud have yet been detected. We will provide additional details once they are available.
(12) Volcanic cloud height: Unknown
(13) Other volcanic cloud information: Unknown
(14) Remarks: Status of the ash cloud can be found at the Alaska Aviation Weather Unit website at http://aawu.arh.noaa.gov/
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Pavel Izbekov, Acting Coordinating Scientist, UAFGI
pavel@gi.alaska.edu (907) 322-4085
(16) Next Notice:
2016-12-29 - Bogoslof, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20161229/0404Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: ORANGE
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: Seismic data from nearby islands detected a volcanic signal from Bogoslof volcano starting at 05:55 AKST (02:55 UTC Dec 29) today. These observations suggest an ash-producing eruption may have occurred. Nothing has yet been observed in satellite data, but the region is covered in high clouds which may prevent such observations. We will provide additional details once they are available.

(12) Volcanic cloud height: Unknown
(13) Other volcanic cloud information: Unknown
(14) Remarks: Status of the ash cloud can be found at the Alaska Aviation Weather Unit website at http://aawu.arh.noaa.gov/
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Pavel Izbekov, Acting Coordinating Scientist, UAFGI
pavel@gi.alaska.edu (907) 322-4085
(16) Next Notice:
2016-12-27 - Bogoslof, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20161227/2156Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: ORANGE
(5) Previous Color Code: RED
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: No further ash emissions have occurred at Bogoslof since the explosive eruption yesterday at 14:05 AKST (23:05 UTC). There has been no indication of elevated seismicity occurring from Bogoslof as measured on nearby island networks over the past 22 hours, however high winds in the region may have obscured volcanic signals over the first 15 hours of this period. While the possibility of further ash-producing eruptions is still present, we are unable to state that such activity is imminent. We are thus lowering the Aviation Color Code to ORANGE and the Alert Level to WATCH.

AVO has no ground-based volcano monitoring equipment on Bogoslof volcano. We continue to monitor satellite images, information from the Worldwide Lightning Location Network pertaining to volcanic-cloud lightning, and data from seismic and infrasound instruments on other islands for indications of volcanic activity. At present, these observations should allow timely detection of additional explosive events.
(12) Volcanic cloud height: no cloud
(13) Other volcanic cloud information: no cloud
(14) Remarks:
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Pavel Izbekov, Acting Coordinating Scientist, UAFGI
pavel@gi.alaska.edu (907) 322-4085
(16) Next Notice:
2016-12-27 - Bogoslof, Aviation Color Code: RED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20161227/0016Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: RED
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: An ash-producing eruption started at 14:05 AKST (23:05 UTC) today and is continuing as recorded by seismic data on nearby islands, by lightning, and as seen in recent satellite images. Cloud-top temperatures from satellite suggest a cloud height of around 30,000 ft asl. Regional winds are from the west-southwest. We are raising the Aviation Color Code to RED and the Alert Level to WARNING.

AVO has no ground-based volcano monitoring equipment on Bogoslof volcano. We continue to monitor satellite images, information from the Worldwide Lightning Location Network pertaining to volcanic-cloud lightning, and data from seismic and infrasound instruments on other islands for indications of volcanic activity. At present, these observations should allow timely detection of additional explosive events.
(12) Volcanic cloud height: Likely around 30,000 ft asl from satellite
(13) Other volcanic cloud information: Winds are from west-southwest
(14) Remarks: Status of the ash cloud can be found at the Alaska Aviation Weather Unit website at http://aawu.arh.noaa.gov/
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Pavel Izbekov, Acting Coordinating Scientist, UAFGI
pavel@gi.alaska.edu (907) 322-4085
(16) Next Notice:
2016-12-25 - Bogoslof, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20161225/0457Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: ORANGE
(5) Previous Color Code: RED
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: No further ash emissions have occurred at Bogoslof since the explosive eruption yesterday at 09:30 AKST (18:30 UTC). Seismicity attributed to the ongoing volcanic unrest has been periodically visible on nearby island networks in the past day and a half, but levels have been generally low since the explosion yesterday. While the possibility of further ash-producing eruptions is still present, we are unable to state that such activity is imminent. We are thus lowering the Aviation Color Code to ORANGE and the Alert Level to WATCH.

AVO has no ground-based volcano monitoring equipment on Bogoslof volcano. We continue to monitor satellite images, information from the Worldwide Lightning Location Network pertaining to volcanic-cloud lightning, and data from seismic and infrasound instruments on other islands for indications of volcanic activity. At present, these observations should allow timely detection of additional explosive events.
(12) Volcanic cloud height: none detected
(13) Other volcanic cloud information: Unknown
(14) Remarks:
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Janet Schaefer, Acting Coordinating Scientist, DGGS
janet.schaefer@alaska.gov (907) 322-4085

(16) Next Notice:
2016-12-23 - Bogoslof, Aviation Color Code: RED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20161223/2012Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: RED
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: An explosive eruption occurred at Bogoslof this morning at about 09:30 AKST (18:30 UTC). A Coast Guard ship in the vicinity reported ash emission as well as ejection of lava and fragmental material. The eruption cloud did not penetrate the regional cloud tops at 30,000 ft and winds are to the north-northeast. According to the Coast Guard, ash emission subsided at about 10:37 AKST (19:37 UTC). On the basis of this information, the Aviation Color Code is raised to RED and the Alert Level to WARNING.

AVO has no ground-based volcano monitoring equipment on Bogoslof volcano. We will monitor satellite images and data from distant seismic and infrasound instruments for indications of significant explosive activity, although high winds in the are presently limit detection abilities.
(12) Volcanic cloud height: Below 30,000 ft
(13) Other volcanic cloud information: Unknown
(14) Remarks: Status of the ash cloud can be found at the Alaska Aviation Weather Unit website at http://aawu.arh.noaa.gov/
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Janet Schaefer, Acting Coordinating Scientist, DGGS
janet.schaefer@alaska.gov (907) 322-4085

(16) Next Notice:
2016-12-22 - Bogoslof, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20161222/0818Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: ORANGE
(5) Previous Color Code: RED
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: The explosive eruption that started at about 01:10 UTC 12/22 (16:10 AKST today) was short-lived and produced an ash cloud as high as 35,000 ft asl that drifted northward. Seismic data recorded on neighboring island networks indicates that the eruption lasted about 30 minutes after which seismicity rapidly declined and remains low. No activity has been observed in recent satellite images or infrasound data. On the basis of this information, the Aviation Color Code is lowered to ORANGE and the Alert Level to WATCH.

AVO has no ground-based volcano monitoring equipment on Bogoslof volcano. We will monitor satellite images and data from distant seismic and infrasound instruments for indications of significant explosive activity.
(12) Volcanic cloud height: none detected
(13) Other volcanic cloud information: Unknown
(14) Remarks: Status of the ash cloud can be found at the Alaska Aviation Weather Unit website at http://aawu.arh.noaa.gov/
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Janet Schaefer, Acting Coordinating Scientist, DGGS
janet.schaefer@alaska.gov (907) 322-4085

(16) Next Notice:
2016-12-22 - Bogoslof, Aviation Color Code: RED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20161222/0232Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: RED
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: An explosive eruption started at about 01:10 UTC 12/22 (16:10 AKST today) as seen in satellite and seismic data from neighboring islands and appeared to last for about 30 minutes. Cloud-top temperatures and wind direction suggest the cloud is as high as 35,000 ft asl, and is moving to the north. On the basis of this information, the Aviation Color Code is raised to RED and the Alert Level to WARNING.

AVO has no ground-based volcano monitoring equipment on Bogoslof volcano and is unable to provide a forecast of future eruptive activity. We will monitor satellite images and data from distant seismic and infrasound instruments for indications of significant explosive activity.
(12) Volcanic cloud height: 35,000 ft asl
(13) Other volcanic cloud information: Drifting north
(14) Remarks:
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Janet Schaefer, Acting Coordinating Scientist, DGGS
janet.schaefer@alaska.gov (907) 322-4085

(16) Next Notice:
2016-12-21 - Bogoslof, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20161221/0605Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: ORANGE
(5) Previous Color Code: RED
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: The explosive eruption of Bogoslof volcano that occurred today at about 00:35 UTC (3:35 pm AKST) was short-lived, lasting approximately 30 minutes, and produced a detached ash cloud that rose to 34,000 ft (10.3 km) above sea level as reported by several pilots. A subsequent pilot report from 01:50 UTC (4:30 pm AKST) indicated that activity had decreased and the cloud was dispersing. The ash cloud was carried southward over the Gulf of Alaska and no ash fell on inhabited areas. No further explosions have been detected in seismic and infrasound networks indicating that the activity has subsided. No activity is apparent in recent nighttime satellite images.

On the basis of this information, the Aviation Color Code is lowered to ORANGE and the Volcano Alert Level to WATCH. AVO has no ground-based volcano monitoring equipment on Bogoslof volcano and is unable to provide a forecast of future eruptive activity. We will monitor satellite images and data from distant seismic and infrasound instruments for indications of significant explosive activity.

Some previous eruptions of Bogoslof have lasted for weeks to months, and further explosive activity could occur with little warning. Mariners in the area should use caution.
(12) Volcanic cloud height: None currently observed
(13) Other volcanic cloud information: Unknown
(14) Remarks:
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Janet Schaefer, Acting Coordinating Scientist, DGGS
janet.schaefer@alaska.gov (907) 322-4085

(16) Next Notice:
2016-12-21 - Bogoslof, Aviation Color Code: RED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20161221/0220Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: RED
(5) Previous Color Code:
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary: A short-lived explosive eruption of Bogoslof volcano was reported by several pilots around 0100 UTC (4:00 pm AST). They reported a volcanic ash cloud rising to an estimated altitude of 34,000 ft (10.3 km). Satellite data show a discrete, short-lived explosion just prior to 0100 UTC that detached and drifted to the south by 0115 UTC. A subsequent pilot report from 0150 UTC indicated that activity had decreased.

On the basis of this information, the Aviation Color Code is increased to Red and the Volcano Alert Level to Warning. There is no ground-based volcano monitoring equipment on Bogoslof volcano so AVO is unable to provide a forecast of future eruptive activity. We will monitor satellite images and data from distant seismic and infrasound instruments for indications of significant explosive activity.
(12) Volcanic cloud height: 34,000 ft
(13) Other volcanic cloud information: Height based on pilot report.
(14) Remarks:
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Janet Schaefer, Acting Coordinating Scientist, UAFGI
janet.schaefer@alaska.gov (907) 322-4085

(16) Next Notice:
2016-11-04 - Cleveland, Aviation Color Code: YELLOW (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20161104/2027Z)
(3) Volcano: Cleveland (VNUM #311240)
(4) Current Color Code: YELLOW
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 52 deg 49 min W 169 deg 56 min
(9) Area: Aleutians
(10) Summit Elevation: 5676 ft (1730 m)
(11) Volcanic Activity Summary: No activity has been observed at Cleveland following the explosion on October 24th. No change in seismicity occurred after the explosion, and there have been no infrasound (pressure sensor) signals detected. Recent satellite views indicate that the lava dome emplaced in late May was mostly destroyed in the explosion and has been replaced with a deep pit within the summit crater. Based on low seismic levels since the eruption, and no observations or reports of continued eruptive activity, AVO is reducing the Aviation Color Code to YELLOW and the Volcano Alert Level to ADVISORY.
(12) Volcanic cloud height: No volcanic clouds observed.
(13) Other volcanic cloud information: No cloud observed.
(14) Remarks: Cleveland volcano forms the western portion of Chuginadak Island, a remote and uninhabited island in the east central Aleutians. The volcano is located about 75 km (45 mi) west of the community of Nikolski, and 1500 km (940 mi) southwest of Anchorage. The most recent significant period of eruption began in February, 2001 and produced 3 explosive events that generated ash clouds as high as 39,000 ft above sea level. The 2001 eruption also produced a lava flow and hot avalanche that reached the sea. Since then, Cleveland has been intermittently active producing small lava flows, often followed by explosions that generate small ash clouds generally below 20,000 ft above sea level. These explosions also launch debris onto the slopes of the cone producing hot pyroclastic avalanches and lahars that sometimes reach the coastline.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jeff Freymueller, Coordinating Scientist, UAFGI
jeff.freymueller@gi.alaska.edu (907) 322-4085
(16) Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at
http://www.avo.alaska.edu
2016-10-24 - Cleveland, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20161024/2219Z)
(3) Volcano: Cleveland (VNUM #311240)
(4) Current Color Code: ORANGE
(5) Previous Color Code: YELLOW
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 52 deg 49 min W 169 deg 56 min
(9) Area: Aleutians
(10) Summit Elevation: 5676 ft (1730 m)
(11) Volcanic Activity Summary: AVO detected an explosion at Cleveland Volcano in both infrasound (air pressure) and seismic data today (10/24/2016) at 13:10 AKDT (21:10 UTC). Residents in Nikolski 45 miles (75 km) from Cleveland reported hearing the explosion. Cloudy weather obscures the volcano in satellite images from 13:30 AKDT (21:30 UTC), however no evidence of an eruption cloud is detected above the weather cloud deck height of 28,000 ft. The summit is currently obscured by cloudy weather in web camera images. Previous Cleveland explosions have typically produced ash emissions.

AVO is raising the color code/alert level of Cleveland Volcano from YELLOW/ADVISORY to ORANGE/WATCH.
(12) Volcanic cloud height: No ash cloud observed above met. cloud deck of 28,000 ft.
(13) Other volcanic cloud information: No cloud observed.
(14) Remarks: Cleveland volcano forms the western portion of Chuginadak Island, a remote and uninhabited island in the east central Aleutians. The volcano is located about 75 km (45 mi) west of the community of Nikolski, and 1500 km (940 mi) southwest of Anchorage. The most recent significant period of eruption began in February, 2001 and produced 3 explosive events that generated ash clouds as high as 39,000 ft above sea level. The 2001 eruption also produced a lava flow and hot avalanche that reached the sea. Since then, Cleveland has been intermittently active producing small lava flows, often followed by explosions that generate small ash clouds generally below 20,000 ft above sea level. These explosions also launch debris onto the slopes of the cone producing hot pyroclastic avalanches and lahars that sometimes reach the coastline.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jeff Freymueller, Coordinating Scientist, UAFGI
jeff.freymueller@gi.alaska.edu (907) 322-4085
(16) Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at
http://www.avo.alaska.edu
2016-08-04 - Pavlof, Aviation Color Code: YELLOW (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20160804/1921Z)
(3) Volcano: Pavlof (VNUM #312030)
(4) Current Color Code: YELLOW
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2016/A86
(8) Volcano Location: N 55 deg 25 min W 161 deg 53 min
(9) Area: Alaska Peninsula
(10) Summit Elevation: 8261 ft (2518 m)
(11) Volcanic Activity Summary: The eruptive activity that was observed intermittently since July 28 has ended or paused. Over the past several days there has been no evidence for continued ash emissions or signs of near surface magma in satellite data. As a result, AVO is lowering the Aviation Color Code to YELLOW and the Volcano Alert Level to ADVISORY.

Occasional views of the volcano in web camera images show small steam plumes at the summit. Seismic activity remains slightly above background levels. Satellite views have been obscured by clouds and intermittent partly clear views of the summit have showed only weakly elevated surface temperatures in one image on 2 August. At the present level of unrest, it is possible for activity to escalate rapidly and for ash emissions to recommence with only subtle precursory signals. AVO will continue to monitor the volcano closely.

(12) Volcanic cloud height: None
(13) Other volcanic cloud information: None
(14) Remarks: Pavlof Volcano is a snow- and ice-covered stratovolcano located on the southwestern end of the Alaska Peninsula about 953 km (592 mi) southwest of Anchorage. The volcano is about 7 km (4.4 mi) in diameter and has active vents on the north and east sides close to the summit. With over 40 historic eruptions, it is one of the most consistently active volcanoes in the Aleutian arc. Eruptive activity is generally characterized by sporadic Strombolian lava fountaining continuing for a several-month period. Ash plumes as high as 49,000 ft ASL have been generated by past eruptions of Pavlof, and during the March 2016 eruption, ash plumes as high as 40,000 feet above sea level were generated and the ash was tracked in satellite data as distant as eastern Canada. The nearest community, Cold Bay, is located 60 km (37 miles) to the southwest of Pavlof.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jeff Freymueller, Coordinating Scientist, UAFGI
jfreymueller@alaska.edu (907) 322-4085
(16) Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at
http://www.avo.a