Volcano observatories issue updates and other types of notifications as activity warrants.
For more information, see: https://volcanoes.usgs.gov/hans2/view/notice/DOI-USGS-NMI-2023-03-24T16:05:29-07:00
For more information, see: https://volcanoes.usgs.gov/hans2/view/notice/DOI-USGS-AVO-2023-03-24T07:26:41-08:00
For more information, see: https://volcanoes.usgs.gov/hans2/view/notice/DOI-USGS-AVO-2023-03-24T07:26:41-08:00
For more information, see: https://volcanoes.usgs.gov/hans2/view/notice/DOI-USGS-AVO-2023-03-24T07:26:41-08:00
For more information, see: https://volcanoes.usgs.gov/hans2/view/notice/DOI-USGS-AVO-2023-03-24T07:26:41-08:00
For more information, see: https://volcanoes.usgs.gov/hans2/view/notice/DOI-USGS-AVO-2023-03-24T07:26:41-08:00
For more information, see: https://volcanoes.usgs.gov/hans2/view/notice/DOI-USGS-AVO-2023-03-24T07:26:41-08:00
For more information, see: https://volcanoes.usgs.gov/hans2/view/notice/DOI-USGS-HVO-2023-03-24T11:57:07-07:00
ALASKA VOLCANO OBSERVATORY WEEKLY UPDATE
U.S. Geological Survey
Friday, March 24, 2023, 11:35 AM AKDT (Friday, March 24, 2023, 19:35 UTC)
SEMISOPOCHNOI (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
Low-level eruptive activity resumed at Semisopochnoi volcano over the past week. On March 18, a vapor plume extending 90 mi (150 km) from Mount Young was observed with no detected seismicity and no significant ash emissions. On March 19, a series of small explosions were detected in seismic and infrasound data and accompanied by minor ash emissions prompting AVO to raise the Aviation Color Code and Volcano Alert Level to ORANGE/WATCH. One small explosion was detected in seismic and infrasound data on March 21. No ash emissions have been observed since March 19 although views of the volcano by satellite and web camera have been mostly obscured by cloud cover. One web camera view on March 22 showed low-level steaming from Mount Young.
Small eruptions producing minor ash deposits within the vicinity of the active north crater of Mount Young and ash clouds usually under 10,000 ft (3 km) above sea level have characterized the recent activity. Additional ash-producing events could occur again with little warning.
Semisopochnoi volcano is monitored by local seismic and infrasound sensors, satellite data, web cameras, and regional infrasound and lightning networks.
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 Young, a three-peaked cone cluster in the southwest part of the caldera. Mount Young has been intermittently active since 2018. The island is uninhabited and part of the Alaska Maritime National Wildlife Refuge. It is located 40 mi (65 km) northeast of Amchitka Island and 130 mi (200 km) west of Adak.
GREAT SITKIN (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 continued to erupt within the summit crater of Great Sitkin at a low rate over the past week. Satellite imagery from March 23 showed the lava flow advancing to the east within the summit crater. Seismicity was at very low levels throughout the week. No signs of unrest were seen in partly cloudy satellite and webcam views.
Great Sitkin is monitored by local seismic and infrasound sensors, satellite data, web cameras, and regional 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 26 miles (43 km) 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 ~1 mile (1.5 km)-diameter summit crater. A steep-sided lava dome, emplaced during the 1974 eruption, occupies the center of the crater. That eruption produced at least one ash cloud that likely exceeded an altitude of 25,000 ft (7.6 km) 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.
TANAGA (VNUM #311080)
51°53'2" N 178°8'35" W, Summit Elevation 5925 ft (1806 m)
Current Volcano Alert Level: ADVISORY
Current Aviation Color Code: YELLOW
Earthquake activity beneath Tanaga Volcano, which began on March 4, peaked on March 9–11 and has declined slowly since. Over the past week, more than 300 earthquakes have been located beneath Tanaga Island, with depths less than 5.5 miles (9.5 km) below sea level. Most of the recent earthquakes locate between Tanaga Volcano and nearby Takawangha volcano, which is about 5 miles (8 km) east of Tanaga Volcano on Tanaga Island. Earthquake activity is ongoing, with multiple magnitude M2 events recorded since peak activity began to decline on March 11. Radar satellite data through March 20 shows recent surface deformation near Sajaka volcano (a subfeature of Tanaga Volcano) suggestive of magma intrusion and consistent with earthquake activity.
Because seismic activity is also elevated at nearby Takawangha volcano, if an eruption were to occur, it is unclear at this stage whether it would come from Tanaga Volcano or Takawangha volcano. No eruptive signals or other signs of unrest have been detected in other data streams or in satellite data.
AVO continues to monitor the activity closely. We expect a renewed increase in shallow seismicity and possibly other signs of unrest, such as gas emissions, elevated surface temperatures, and additional changes in surface deformation to precede any eruption.
Tanaga is monitored with a local seismic network, a single local infrasound sensor, regional infrasound and lightning sensors, and satellite imagery.
Tanaga Island lies in the Andreanof Islands approximately 62 miles (100 km) west of the community of Adak and 1260 miles (2025 km) SW of Anchorage. The northern half of the island is home to the Tanaga volcanic complex, comprising three main volcanic edifices. Tanaga Volcano is the tallest of these (5,925 ft or 1,806 m) and lies in the center of the complex. The last reported eruption of Tanaga occurred in 1914 and earlier eruptions were reported in 1763-1770, 1791, and 1829. Reports of these eruptions are vague, but deposits on the flanks of the volcano show that typical eruptions produce blocky lava flows and occasional ash clouds. Eruptions have occurred both from the summit vent and a 5,197 ft (1,584 m)-high satellite vent on the volcano's northeast flank. Immediately west of Tanaga volcano lies Sajaka, a 4,443 ft (1,354 m)-high compound edifice with an older cone to the east that collapsed into the sea within the last few thousand years, and a new cone that has grown in the breach. The new cone is 4,305 ft (1,312 m) high and consists of steeply dipping, interbedded cinders and thin, spatter-fed lava flows. To the east of Tanaga lies Takawangha, which is separated from the other active volcanic vents by a ridge of older rock. No historical eruptions are known from Sajaka or Takawangha; however, field work shows that recent eruptions have occurred, and it is possible that historic eruptions attributed only to Tanaga may instead have come from these other vents.
TAKAWANGHA (VNUM #311090)
51°52'1" N 178°1'37" W, Summit Elevation 4754 ft (1449 m)
Current Volcano Alert Level: ADVISORY
Current Aviation Color Code: YELLOW
Earthquake activity beneath Takawangha volcano, which began in the fall of 2022, peaked on March 9–11 and has declined slowly since. More than 300 earthquakes have been located over the past week beneath Tanaga Island, with depths less than 5.5 miles (9 km) below sea level. Most of the recent earthquakes locate between Takawangha volcano and nearby Tanaga Volcano, which is about 5 miles (8 km) west of Takawangha volcano on Tanaga Island. Earthquake activity is ongoing, with multiple magnitude M2 events recorded since peak activity began to decline on March 11.
No eruptive signals or other signs of unrest have been detected in other data streams or in satellite data.
AVO continues to monitor the activity closely. We expect a renewed increase in shallow seismicity and possibly other signs of unrest, such as gas emissions, elevated surface temperatures, and surface deformation to precede any future eruption.
Takawangha is monitored with a local seismic network, a single local infrasound sensor, regional infrasound and lightning sensors, and satellite imagery.
Takawangha is a remote, 4,754 ft (1,449 m)-high stratovolcano located on the northeast portion of Tanaga Island, roughly 59 miles (95 km) 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.
ANIAKCHAK (VNUM #312090)
56°54'21" N 158°12'32" W, Summit Elevation 4400 ft (1341 m)
Current Volcano Alert Level: ADVISORY
Current Aviation Color Code: YELLOW
Seismicity beneath Aniakchak volcano remained above background levels. The largest earthquakes during the past week had magnitudes between M2 and M3. The earthquakes are occurring below the center of the caldera and to the east of the volcano at depths shallower than about 4 miles (6 km). Radar satellite data through March 23 shows rapid uplift of the ground surface within the central portion of the caldera, consistent with magma intrusion at about 4 km depth. No eruptive activity observed in satellite views.
Increases in seismic activity and surface deformation have been detected previously at other similar volcanoes, with no subsequent eruptions. We expect additional shallow seismicity and possibly other signs of unrest, such as gas emissions, elevated surface temperatures, and additional changes in surface deformation to precede any future eruption, if one were to occur.
AVO monitors Aniakchak with a local network, which consists of six seismometers, a web camera, and a single infrasound sensor, as well as satellite remote sensing data and regional infrasound and lightning networks. Several of the seismic stations, however, stopped transmitting data on March 4 due to low power levels. Two stations remain in operation, but we are unable to locate smaller earthquakes due to the outage.
Aniakchak volcano, located in the central portion of the Alaska Peninsula, consists of a stratovolcano edifice with a 6 miles (10 km) diameter summit caldera. The caldera-forming eruption occurred around 3,500 years ago. Postcaldera eruptions have produced lava domes, tuff cones, and larger spatter and scoria cone structures including Half-Cone and Vent Mountain all within the caldera. The most recent eruption occurred in 1931 and created a new vent and lava flows on the western caldera floor while spreading ash over much of southwestern Alaska. Aniakchak volcano is 15 miles (25 km) southeast of the nearest community, Port Heiden, and 416 miles (670 km) southwest of Anchorage, Alaska.
TRIDENT (VNUM #312160)
58°14'3" N 155°6'9" W, Summit Elevation 3599 ft (1097 m)
Current Volcano Alert Level: ADVISORY
Current Aviation Color Code: YELLOW
Seismicity beneath Trident Volcano remained above background levels, although most of the earthquakes over the past week have been small (less than ~M1. No eruptive activity or other signs of unrest were seen in satellite or webcam views.
The current period of seismic unrest began on August 24, 2022. Earthquake depths at the beginning of the swarm were mostly deep, around 16 miles (25 km) below sea level and became progressively shallower to around 3 miles (5 km) over the following four days. Since late August 2022, most earthquakes have occurred within the shallow crust, with depths less than 6 km below sea level. Since January 1, 2023, earthquakes under Trident are occurring at an average rate of about ten per day or less.
Increases in seismic activity have been detected previously at Trident Volcano and other similar volcanoes, with no subsequent eruptions. We expect additional shallow seismicity and other signs of unrest, such as gas emissions, elevated surface temperatures, and surface deformation to precede any future eruption, if one were to occur.
AVO monitors Trident Volcano with a local network of seismometers, a webcam, remote sensing data, and regional infrasound and lightning networks.
Trident is one of the Katmai group of volcanoes located within Katmai National Park and Preserve on the Alaska Peninsula. Trident consists of a complex of four cones and numerous lava domes, all andesite and dacite in composition, that reach as high as 6,115 ft (98 km) above sea level. An eruption beginning in 1953 constructed the newest cone, Southwest Trident, and four lava flows on the flank of the older complex. This eruption continued through 1974 and produced ash (an initial plume rose to 30,000 ft or 48 km asl), bombs, and lava at various times. Fumaroles remain active on the summit of Southwest Trident and on the southeast flank of the oldest, central cone. Trident is located 92 miles (148 km) southeast of King Salmon and 273 miles (440 km) southwest of Anchorage.
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
Pavel Izbekov, Acting Coordinating Scientist, UAFGI peizbekov@alaska.edu (907) 378-5460
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, March 21, 2023, 10:02 AM PDT (Tuesday, March 21, 2023, 17:02 UTC)
Monitored CALIFORNIA VOLCANOES
Current Volcano Alert Level: all NORMAL
Current Aviation Color Code: all GREEN
Activity Update: All volcanoes monitored by CalVO show normal background earthquake activity and ground movement. Monitored volcanoes include Mount Shasta, Medicine Lake Volcano, Lassen Volcanic Center, Clear Lake Volcanic Field, Long Valley Volcanic Region, Coso Volcanic Field, Ubehebe Craters, and Salton Buttes.
Past Week Observations for March 13, 2023 (0000h PDT) through March 19, 2023 (2359h PDT):
Two earthquakes greater than M1 were detected at the Clear Lake Volcanic Field, the largest having a magnitude of M1.2. Typical seismicity was recorded at The Geysers geothermal field south of the Clear Lake Volcanic Field; 97 earthquakes greater than M1 were detected, with the largest having a magnitude of M2.5.
Three earthquakes greater than M1 were recored in Long Valley Caldera, with the largest having a magnitude of M1.6. Two earthquakes greater than M1 were recorded in the Sierra Nevada range south of Long Valley Caldera, with the largest having a magnitude of M1.5. These earthquakes occur within a regional fault zone and are related to tectonic movement not associated with the volcano.
One earthquake greater than M1 was recored at Coso Volcanic Field, with a magnitude of M1.5.
Two earthquakes greater than M1 were recored at Salton Buttes, with the largest having a magnitude of M2.5.
Network Outage: Data transmission from the seismic network at Lassen Volcanic Center that was disrupted on March 1 was restored on March 17.
CalVO's Weekly Update only highlights volcanoes which have experienced seismic activity or volcanic unrest. If there are no comments for a volcano, CalVO has detected no earthquakes with magnitudes greater than or equal to M1.0, or any other kind of unrest. Only earthquakes with magnitudes greater than M1.0 are reported here.
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, March 24, 2023, 12:42 PM PDT (Friday, March 24, 2023, 19:42 UTC)
CASCADE RANGE (VNUM #)
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: During the past week, earthquakes consistent with background level activity were detected at Mount St. Helens, Mount Hood, and Mount Rainier.
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.
Website Resources
For images, graphics, and general information on Cascade Range volcanoes: https://www.usgs.gov/observatories/cvo
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/programs/VHP/volcano-notifications-deliver-situational-information
CONTACT INFORMATION:
Jon Major, Scientist-in-Charge, Cascades Volcano Observatory, jjmajor@usgs.gov
General inquiries: vhpweb@usgs.gov
Media: Ryan McClymont, PIO, USGS Office of Communications and Publishing rmcclymont@usgs.gov
HAWAIIAN VOLCANO OBSERVATORY DAILY UPDATE
U.S. Geological Survey
Friday, March 24, 2023, 9:21 AM HST (Friday, March 24, 2023, 19:21 UTC)
KILAUEA (VNUM #332010)
19°25'16" N 155°17'13" W, Summit Elevation 4091 ft (1247 m)
Current Volcano Alert Level: ADVISORY
Current Aviation Color Code: YELLOW
Activity Summary: Kīlauea volcano is not erupting. The summit eruption of Kīlauea volcano, within Halemaʻumaʻu crater, remains paused. Lava is no longer flowing on the crater floor. Resumption of eruptive activity may occur in the near future with little or no warning. No significant changes have been observed along either of the volcano's rift zones. Low rates of ground deformation and modest rates of seismicity continue across the volcano.
Halemaʻumaʻu Lava Lake Observations: No active lava has been observed over the past 24 hours. A live-stream video of the inactive western lava lake area is available at https://www.youtube.com/usgs/live.
Summit Observations: Uēkahuna tiltmeter is recording a relatively flat trend in the bottom part of a DI event. Seismicity is at background levels. The last SO2 emission rate of approximately 321 tonnes per day (t/d) was measured on March 21.
The magnitude 3.9 earthquake that occured on the Kaʻōiki fault zone of Mauna Loa at 5:04 p.m. yesterday was followed in the next 5 hours by over 20 small aftershocks. This earthquake was not related to magmatic activity within Mauna Loa and had no effect on Kīlaueaʻs magmatic plumbing system.
Rift Zone Observations: No unusual activity has been noted along the Rift Zones; steady rates of ground deformation and seismicity continue along both. Measurements from continuous gas monitoring stations in the middle East Rift Zone are below detection limits for SO2.
Hazard Analysis: Recent eruptions at the summit of Kīlauea Volcano have been occurring within a closed area of Hawaiʻi Volcanoes National Park. High levels of volcanic gas are the primary hazard of concern, as this hazard can have far-reaching effects downwind. Large amounts of volcanic gas—primarily water vapor (H2O), carbon dioxide (CO2), and sulfur dioxide (SO2)—are continuously released during eruptions of Kīlauea. 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 the volcano. 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 lava fountains that fall downwind and dust the ground within a few hundred meters (yards) of the erupting fissure 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 the 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 Hawaiʻi 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 such dustings 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-and-video-chronology
Kīlauea lava-flow maps: https://www.usgs.gov/volcanoes/kilauea/maps
Kīlauea FAQs: https://www.usgs.gov/volcanoes/kilauea/faqs
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 and American Samoa.
CONTACT INFORMATION:
Subscribe to these messages: https://volcanoes.usgs.gov/vns2/
Summary of volcanic hazards from eruptions: https://www.usgs.gov/observatories/hvo/hazards
Recent earthquakes in Hawaiʻi (map and list): https://www.usgs.gov/observatories/hvo
Explanation of Volcano Alert Levels and Aviation Color Codes: https://www.usgs.gov/programs/VHP/volcanic-alert-levels-characterize-conditions-us-volcanoes
NORTHERN MARIANA ISLANDS VOLCANO OBSERVATORY DAILY UPDATE
U.S. Geological Survey
Saturday, March 25, 2023, 9:05 AM ChST (Friday, March 24, 2023, 23:05 UTC)
Report prepared by the U.S. Geological Survey.
AHYI SEAMOUNT (VNUM #284141)
20°25'12" N 145°1'48" E, Summit Elevation -449 ft (-137 m)
Current Volcano Alert Level: ADVISORY
Current Aviation Color Code: YELLOW
No significant activity from Ahyi Seamount was detected in remote pressure sensor or satellite data over the past day.
There are no local monitoring stations near Ahyi Seamount, which limits our ability to detect and characterize volcanic unrest there. We will continue to monitor available remote hydrophonic, seismic, and satellite data closely.
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 (907) 786-7497
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
Wednesday, March 1, 2023, 9:30 AM MST (Wednesday, March 1, 2023, 16:30 UTC)
YELLOWSTONE (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
There were no recorded eruptions of Steamboat Geyser during the month of February, and the total number of eruptions for the year remains at two. The Norris temperature monitoring network and seismic station YNM have been inaccessible since mid to late February due to a local power failure—the Norris Museum is difficult to access during winter months—but the streamgage on Tantalus Creek, through which all water from Norris Geyser Basin drains, did not record obvious spikes that would be associated with Steamboat eruptions.
Seismicity
During February 2023, the University of Utah Seismograph Stations, responsible for the operation and analysis of the Yellowstone Seismic Network, located 168 earthquakes in the Yellowstone National Park region. The largest event of the month was a minor earthquake of magnitude 2.9 located about 11 miles northeast of West Yellowstone, Montana, on February 7 at 8:44 PM MST. This event was part of a swarm of 76 earthquakes that occurred in the area during February 4–11.
In addition, 48 earthquakes were added to the ongoing seismicity that began last summer about 14 miles south-southwest of Mammoth Hot Springs in Yellowstone National Park. The largest earthquake of the month in this sequence, a magnitude 2.4 event, occurred on February 14 at 3:03 AM MST.
Earthquake sequences like these are common and account for roughly 50% of the total seismicity in the Yellowstone region.
Yellowstone earthquake activity is currently at background levels.
Ground Deformation
Continuous GPS stations in Yellowstone Caldera continued to record gradual subsidence at a rate of several centimeters (about 1 inch) per year, which has been ongoing since 2015. No significant deformation has been recorded in the area of Norris Geyser Basin since the end of last summer. Snow and ice accumulation on GPS antennas due to winter storms cause occasional apparent subsidence of 1–3 centimeters, but this does not represent real ground motion and recovers itself quickly once the antennas are free of snow/ice.
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)
| (1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA) | |
| (2) Issued: | (20230321/1836Z) |
| (3) Volcano: | Kilauea (VNUM #332010) |
| (4) Current Color Code: | YELLOW |
| (5) Previous Color Code: | ORANGE |
| (6) Source: | Hawaiian Volcano Observatory |
| (7) Notice Number: | 2023/H115 |
| (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 is no longer erupting. Lava supply to the Halemaʻumaʻu lava lake ceased on March 7 based upon lava lake levels and behavior of the crater floor. 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. Seismicity and deformation patterns remain unsettled. Resumption of eruptive activity may occur in the near future with little or no warning. Potential remains for resumption of this eruption or initiation of a new eruption at or near the summit of Kīlauea. Hazards are still present on Kīlauea and are described below. Residents and visitors should stay informed and follow County of Hawai‘i and Hawaiʻi Volcanoes National Park guidelines. For more information about the meaning of aviation color codes, see https://www.usgs.gov/programs/VHP/volcanic-alert-levels-characterize-conditions-us-volcanoes
|
| (12) Volcanic cloud height: | N/A |
| (13) Other volcanic cloud information: | N/A |
| (14) Remarks: | Hazard Analysis: 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 notice odors of these gases occasionally. 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. Please see the Hawaiʻi Volcanoes National Park website for visitor information: https://www.nps.gov/havo/index.htm.
|
| (15) Contacts: | |
| (16) Next Notice: | Kīlauea updates will now be issued weekly on Tuesdays. Should volcanic activity change significantly, a new VAN will be issued. Regularly scheduled updates are posted on the HVO website at https://www.usgs.gov/volcanoes/kilauea/volcano-updates More Information:
|
| (1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA) | |
| (2) Issued: | (20230319/2047Z) |
| (3) Volcano: | Semisopochnoi (VNUM #311060) |
| (4) Current Color Code: | ORANGE |
| (5) Previous Color Code: | YELLOW |
| (6) Source: | Alaska Volcano Observatory |
| (7) Notice Number: | 2023/A340 |
| (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: |
Low-level ash emissions from the north crater of Mount Young at Semisopochnoi were observed in several web camera images over the past day. In addition, small explosions and volcanic tremor have resumed during the same time period. Ash emissions have not been detected in satellite data, although a vapor plume extending 150 km (90 miles) from Mount Young was observed yesterday in satellite data. This activity is similar to eruptive activity observed intermittently over the last few years at Semisopochnoi. The Aviation Color Code and Volcano Alert Level are being raised to ORANGE/WATCH. Small eruptions producing minor ash deposits within the vicinity of the active north crater of Mount Cerberus and ash clouds usually under 10,000 ft (3 km) above sea level have characterized the recent activity and more ash-producing events could occur again with little warning. Semisopochnoi is monitored by a local seismic and infrasound network, local web cameras, regional lightning and infrasound sensors, and satellite data. |
| (12) Volcanic cloud height: | 3000 ft |
| (13) Other volcanic cloud information: | ash |
| (14) Remarks: | Remote Semisopochnoi volcano occupies the largest, young volcanic island in the western Aleutians. The uninhabited island is part of the Alaska Maritime National Wildlife Refuge. It is located 65 km (40 mi) northeast of Amchitka Island and 200 km (130 mi) west of Adak, Alaska. Semisopochnoi volcano is dominated by an 8-km (5-mile) 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. The north cone of Mount Young, in the southwest part of the caldera, is the site of the current eruption, which began in 2018. The last known eruption prior to 2018 was in 1987 from Sugarloaf Peak on the south coast of the island. |
| (15) Contacts: | Michelle Coombs, Scientist-in-Charge, USGS mcoombs@usgs.gov (907) 786-7497 David Fee, Coordinating Scientist, UAFGI dfee1@alaska.edu (907) 378-5460 |
| (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. |
| (1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA) | |
| (2) Issued: | (20230316/1932Z) |
| (3) Volcano: | Mauna Loa (VNUM #332020) |
| (4) Current Color Code: | GREEN |
| (5) Previous Color Code: | YELLOW |
| (6) Source: | Hawaiian Volcano Observatory |
| (7) Notice Number: | 2023/H109 |
| (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: |
Mauna Loa has been quiet for the past three months since the eruption ended on December 13, 2022. The number of earthquakes beneath Mauna Loa's summit has returned to background levels. Inflation of Mauna Loa continues as magma replenishes the summit magma chamber. Accordingly, the USGS Hawaiian Volcano Observatory (HVO) is lowering the Volcano Alert Level for ground-based hazards from ADVISORY to NORMAL and the Aviation Color Code from YELLOW to GREEN. In conjunction with this change, Mauna Loa updates will change from weekly to monthly, with the next monthly update on April 6, 2023. For more information about the meaning of aviation color codes, see https://www.usgs.gov/programs/VHP/volcanic-alert-levels-characterize-conditions-us-volcanoes |
| (12) Volcanic cloud height: | None |
| (13) Other volcanic cloud information: | None |
| (14) Remarks: | HVO continues to closely monitor Mauna Loa for signs of renewed activity. Should volcanic activity change significantly a new Volcanic Activity Notice will be issued immediately. |
| (15) Contacts: | |
| (16) Next Notice: | Mauna Loa monthly updates issued monthly on Thursdays beginning April 6, 2023. Should volcanic activity change significantly a new VAN will be issued. Regularly scheduled updates on the status of Mauna Loa will be posted on the HVO website at https://www.usgs.gov/volcanoes/mauna-loa/volcano-updates More Information:
|
| (1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA) | |
| (2) Issued: | (20230316/1840Z) |
| (3) Volcano: | Tanaga (VNUM #311080) |
| (4) Current Color Code: | YELLOW |
| (5) Previous Color Code: | ORANGE |
| (6) Source: | Alaska Volcano Observatory |
| (7) Notice Number: | 2023/A314 |
| (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: |
Earthquake activity near Tanaga Volcano has decreased in both rate and magnitude from the peak of the swarm on March 9 – 11. The significant decline in earthquake activity decreases the potential for an eruption at the volcano. No other signs of unrest have been detected in other monitoring data. AVO is therefore lower the Aviation Color Code to Yellow and the Volcano Alert Level to ADVISORY. Seismic activity has also declined at Takawangha volcano, which is about 8 km (5 miles) east of Tanaga Volcano on Tanaga Island. The Aviation Color Code/Alert Level has also been lowered to YELLOW/ADVISORY for Takawangha. AVO continues to monitor the activity closely and seismic analysts are locating events as time permits. Earthquakes are occurring under Tanaga Island at a rate of up to several per minute. The largest event over the past 24 hours was a M3.1 located between Takawangha volcano and Tanaga Volcano. Tanaga is monitored with a local seismic network, a single local infrasound sensor, regional infrasound and lightning sensors, and satellite imagery. For current monitoring data: https://avo.alaska.edu/activity/Tanaga.php |
| (12) Volcanic cloud height: | None observed |
| (13) Other volcanic cloud information: | None observed |
| (14) Remarks: | Tanaga Island lies in the Andreanof Islands approximately 100 km (62 miles) west of the community of Adak and 2025 km (1260 miles) SW of Anchorage. The northern half of the island is home to the Tanaga volcanic complex, comprising three main volcanic edifices. Tanaga Volcano is the tallest of these (1,806 m or 5,925 ft) and lies in the center of the complex. The last reported eruption of Tanaga occurred in 1914 and earlier eruptions were reported in 1763-1770, 1791, and 1829. Reports of these eruptions are vague, but deposits on the flanks of the volcano show that typical eruptions produce blocky lava flows and occasional ash clouds. Eruptions have occurred both from the summit vent and a 1,584 m (5,197 ft)-high satellite vent on the volcano's northeast flank. Immediately west of Tanaga volcano lies Sajaka, a 1,354 m (4,443 ft)-high compound edifice with an older cone to the east that collapsed into the sea within the last few thousand years, and a new cone that has grown in the breach. The new cone is 1,312 m (4,305 ft) high and consists of steeply dipping, interbedded cinders and thin, spatter-fed lava flows. To the east of Tanaga lies Takawangha, which is separated from the other active volcanic vents by a ridge of older rock. Takawangha's 1,449 m (4,754 ft)-high 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, and could produce localized debris avalanches. No historical eruptions are known from Sajaka or Takawangha; however, field work shows that recent eruptions have occurred and it is possible that historic eruptions attributed only to Tanaga may instead have come from these other vents. |
| (15) Contacts: | Michelle Coombs, Scientist-in-Charge, USGS mcoombs@usgs.gov (907) 786-7497 David Fee, Coordinating Scientist, UAFGI dfee1@alaska.edu (907) 378-5460 |
| (16) Next Notice: | |
| (1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA) | |
| (2) Issued: | (20230316/1839Z) |
| (3) Volcano: | Takawangha (VNUM #311090) |
| (4) Current Color Code: | YELLOW |
| (5) Previous Color Code: | ORANGE |
| (6) Source: | Alaska Volcano Observatory |
| (7) Notice Number: | 2023/A315 |
| (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: |
Earthquake activity near Takawangha volcano has decreased in both rate and magnitude from the peak of the swarm on March 9 – 11. The significant decline in earthquake activity decreases the potential for an eruption at the volcano. No other signs of unrest have been detected in other monitoring data. AVO is therefore lower the Aviation Color Code to YELLOW and the Volcano Alert Level to ADVISORY. Seismic activity has also declined at Tanaga Volcano, which is about 8 km (5 miles) west of Takawangha on Tanaga Island. The Aviation Color Code/Alert Level has also been lowered to YELLOW/ADVISORY for Tanaga Volcano. AVO continues to monitor the activity closely and seismic analysts are locating events as time permits. Earthquakes are occurring under Tanaga Island at a rate of up to several per minute. The largest event over the past 24 hours was a M3.1 located between Takawangha volcano and Tanaga Volcano. Takawangha is monitored with a local seismic network, a single local infrasound sensor, regional infrasound and lightning sensors, and satellite imagery. For current monitoring data: https://avo.alaska.edu/activity/Takawangha.php |
| (12) Volcanic cloud height: | None observed |
| (13) Other volcanic cloud information: | None observed |
| (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 David Fee, Coordinating Scientist, UAFGI dfee1@alaska.edu (907) 378-5460 |
| (16) Next Notice: | |
| (1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA) | |
| (2) Issued: | (20230310/0222Z) |
| (3) Volcano: | Takawangha (VNUM #311090) |
| (4) Current Color Code: | ORANGE |
| (5) Previous Color Code: | YELLOW |
| (6) Source: | Alaska Volcano Observatory |
| (7) Notice Number: | 2023/A225 |
| (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: |
Over the past 48 hours, earthquake activity near Takawangha volcano has been elevated and continues. This sustained activity indicates an increased potential for eruption at the volcano. Therefore AVO is raising the Aviation Color Code to ORANGE and the Volcano Alert Level to WATCH. Seismic activity is also elevated at Tanaga Volcano, which is about 8 km (5 miles) west of Takawangha on Tanaga Island. If an eruption were to occur, it is uncertain at this stage if it would come from Takawangha or Tanaga. AVO analysts continue to monitor the situation closely, and locate events as time permits. Earthquakes are occurring under Tanaga Island at a rate of up to several per minute. The largest event over the past 24 hours was a M3.9 located under Tanaga Volcano. No eruptive activity or signs of unrest have been detected in satellite or other monitoring data. Takawangha is monitored with a local seismic network, a single local infrasound sensor, regional infrasound and lightning sensors, and satellite imagery. For current monitoring data: https://avo.alaska.edu/activity/Takawangha.php |
| (12) Volcanic cloud height: | None observed |
| (13) Other volcanic cloud information: | None observed |
| (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 David Fee, Coordinating Scientist, UAFGI dfee1@alaska.edu (907) 322-4085 |
| (16) Next Notice: | |
| (1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA) | |
| (2) Issued: | (20230310/0219Z) |
| (3) Volcano: | Tanaga (VNUM #311080) |
| (4) Current Color Code: | ORANGE |
| (5) Previous Color Code: | YELLOW |
| (6) Source: | Alaska Volcano Observatory |
| (7) Notice Number: | 2023/A268 |
| (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: |
Over the past 48 hours, earthquake activity near Tanaga Volcano has been elevated and continues. This sustained activity indicates an increased potential for eruption at the volcano. Therefore AVO is raising the Aviation Color Code to ORANGE and the Volcano Alert Level to WATCH. Seismic activity is also elevated at Takawangha volcano, which is about 8 km (5 miles) east of Tanaga on Tanaga Island. If an eruption were to occur, it is uncertain at this stage if it would come from Tanaga or Takawangha. AVO analysts continue to monitor the situation closely, and locate events as time permits. Earthquakes are occurring under Tanaga Island at a rate of up to several per minute. The largest event over the past 24 hours was a M3.9 located under Tanaga Volcano. No eruptive activity or signs of unrest have been detected in satellite or other monitoring data. Tanaga is monitored with a local seismic network, a single local infrasound sensor, regional infrasound and lightning sensors, and satellite imagery. For current monitoring data: https://avo.alaska.edu/activity/Tanaga.php |
| (12) Volcanic cloud height: | None observed |
| (13) Other volcanic cloud information: | None observed |
| (14) Remarks: | Tanaga Island lies in the Andreanof Islands approximately 100 km (62 miles) west of the community of Adak and 2025 km (1260 miles) SW of Anchorage. The northern half of the island is home to the Tanaga volcanic complex, comprising three main volcanic edifices. Tanaga Volcano is the tallest of these (1,806 m or 5,925 ft) and lies in the center of the complex. The last reported eruption of Tanaga occurred in 1914 and earlier eruptions were reported in 1763-1770, 1791, and 1829. Reports of these eruptions are vague, but deposits on the flanks of the volcano show that typical eruptions produce blocky lava flows and occasional ash clouds. Eruptions have occurred both from the summit vent and a 1,584 m (5,197 ft)-high satellite vent on the volcano's northeast flank. Immediately west of Tanaga volcano lies Sajaka, a 1,354 m (4,443 ft)-high compound edifice with an older cone to the east that collapsed into the sea within the last few thousand years, and a new cone that has grown in the breach. The new cone is 1,312 m (4,305 ft) high and consists of steeply dipping, interbedded cinders and thin, spatter-fed lava flows. To the east of Tanaga lies Takawangha, which is separated from the other active volcanic vents by a ridge of older rock. Takawangha's 1,449 m (4,754 ft)-high 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, and could produce localized debris avalanches. No historical eruptions are known from Sajaka or Takawangha; however, field work shows that recent eruptions have occurred and it is possible that historic eruptions attributed only to Tanaga may instead have come from these other vents. |
| (15) Contacts: | Michelle Coombs, Scientist-in-Charge, USGS mcoombs@usgs.gov (907) 786-7497 David Fee, Coordinating Scientist, UAFGI dfee1@alaska.edu (907) 378-5460
|
| (16) Next Notice: | |
| (1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA) | |
| (2) Issued: | (20230308/0715Z) |
| (3) Volcano: | Tanaga (VNUM #311080) |
| (4) Current Color Code: | YELLOW |
| (5) Previous Color Code: | GREEN |
| (6) Source: | Alaska Volcano Observatory |
| (7) Notice Number: | 2023/A266 |
| (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: |
Earthquake activity beneath Tanaga Volcano began to increase slowly starting at about 1:30 PM AKST today. At roughly 8:45 PM AKST this evening, the activity escalated with earthquakes occurring as often as 2 or 3 each minute. Initial locations of these earthquakes place them at shallow depths beneath the summit of Tanaga Volcano, and the largest of these earthquakes have magnitudes between 2 and 3. In response to this increase in seismicity, we are raising the Aviation Color Code to YELLOW and the Volcano Alert Level to ADVISORY. |
| (12) Volcanic cloud height: | None |
| (13) Other volcanic cloud information: | None |
| (14) Remarks: | Tanaga Island lies in the Andreanof Islands approximately 100 km (62 miles) west of the community of Adak and 2025 km (1260 miles) SW of Anchorage. The northern half of the island is home to the Tanaga volcanic complex, comprising three main volcanic edifices. Tanaga Volcano is the tallest of these (1,806 m or 5,925 ft) and lies in the center of the complex. The last reported eruption of Tanaga occurred in 1914 and earlier eruptions were reported in 1763-1770, 1791, and 1829. Reports of these eruptions are vague, but deposits on the flanks of the volcano show that typical eruptions produce blocky lava flows and occasional ash clouds. Eruptions have occurred both from the summit vent and a 1,584 m (5,197 ft)-high satellite vent on the volcano's northeast flank. Immediately west of Tanaga volcano lies Sajaka, a 1,354 m (4,443 ft)-high compound edifice with an older cone to the east that collapsed into the sea within the last few thousand years, and a new cone that has grown in the breach. The new cone is 1,312 m (4,305 ft) high and consists of steeply dipping, interbedded cinders and thin, spatter-fed lava flows. To the east of Tanaga lies Takawangha, which is separated from the other active volcanic vents by a ridge of older rock. Takawangha's 1,449 m (4,754 ft)-high 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, and could produce localized debris avalanches. No historical eruptions are known from Sajaka or Takawangha; however, field work shows that recent eruptions have occurred and it is possible that historic eruptions attributed only to Tanaga may instead have come from these other vents. |
| (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: | |
| (1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA) | |
| (2) Issued: | (20230223/0143Z) |
| (3) Volcano: | Aniakchak (VNUM #312090) |
| (4) Current Color Code: | YELLOW |
| (5) Previous Color Code: | GREEN |
| (6) Source: | Alaska Volcano Observatory |
| (7) Notice Number: | 2023/A192 |
| (8) Volcano Location: | N 56 deg 54 min W 158 deg 12 min |
| (9) Area: | Alaska Peninsula |
| (10) Summit Elevation: | 4400 ft (1341 m) |
| (11) Volcanic Activity Summary: |
The number of earthquakes beneath Aniakchak volcano has recently increased and shifted to shallower depths. Due to this increase in seismic activity to above-background levels, the Alaska Volcano Observatory is raising the Aviation Color Code to YELLOW and the Volcano Alert Level to ADVISORY. There have been no signs of unrest in other monitoring data. Background seismicity at Aniakchak has mostly been characterized by deep (>15 km or 9.3 miles), long-period events occurring at a rate of ~4 earthquakes per month. From October 2022 to present, the rate of earthquakes has been more elevated and characterized by shallower earthquakes at depths less than 9 km (5.6 miles) below sea level. The earthquake rate has further increased since January 31 with dozens of earthquakes detected per day, including a M3.7 earthquake on February 17. There is no indication that an eruption of Aniakchak is imminent, or that one will occur. Increases in seismic activity have been detected previously at other similar volcanoes, with no subsequent eruptions. We expect additional shallow seismicity and other signs of unrest, such as gas emissions, elevated surface temperatures, and surface deformation to precede any future eruption, if one were to occur. Should activity increase, AVO will issue further notices. AVO monitors Aniakchak with a local network, which consists of six seismometers, a web camera, and a single infrasound sensor, as well as satellite remote sensing data and regional infrasound and lightning networks. To view current monitoring data, see https://avo.alaska.edu/activity/Aniakchak.php |
| (12) Volcanic cloud height: | none |
| (13) Other volcanic cloud information: | none |
| (14) Remarks: | Aniakchak volcano, located in the central portion of the Alaska Peninsula, consists of a stratovolcano edifice with a 10 km (6 mile) diameter summit caldera. The caldera-forming eruption occurred around 3,500 years ago. Postcaldera eruptions have produced lava domes, tuff cones, and larger spatter and scoria cone structures including Half-Cone and Vent Mountain all within the caldera. The most recent eruption occurred in 1931 and created a new vent and lava flows on the western caldera floor while spreading ash over much of southwestern Alaska. Aniakchak volcano is 25 km (15 miles) southeast of the nearest community, Port Heiden, and 670 km (416 miles) southwest of Anchorage, Alaska. |
| (15) Contacts: | Michelle Coombs, Scientist-in-Charge, USGS mcoombs@usgs.gov (907) 786-7497 Társilo Girona, Acting Coordinating Scientist, UAFGI tarsilo.girona@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. |
| (1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA) | |
| (2) Issued: | (20230222/1847Z) |
| (3) Volcano: | Trident (VNUM #312160) |
| (4) Current Color Code: | YELLOW |
| (5) Previous Color Code: | GREEN |
| (6) Source: | Alaska Volcano Observatory |
| (7) Notice Number: | 2023/A184 |
| (8) Volcano Location: | N 58 deg 14 min W 155 deg 6 min |
| (9) Area: | Alaska Peninsula |
| (10) Summit Elevation: | 3599 ft (1097 m) |
| (11) Volcanic Activity Summary: |
Earthquake activity beneath Trident Volcano has recently increased and is ongoing, although there have been no signs of unrest in other monitoring data. Due to this increase in seismic activity to above-background levels, the Alaska Volcano Observatory is raising the Aviation Color Code to YELLOW and the Volcano Alert Level to ADVISORY. The current period of seismic unrest, or earthquake swarm, began on August 24, 2022. Earthquake depths at the beginning of the swarm were mostly deep, around 25 km (16 miles) below sea level, and became progressively shallower to around 5 km (3 miles) over the following four days. Since late August 2022, most earthquakes have been located in the shallow crust, with depths less than 6 km below sea level. Since January 1, 2023, earthquakes under Trident are occurring at an average rate of about ten per day. The largest event since August was a M4.6 quake on November 20, but most earthquakes are much smaller. A few episodes of weak seismic tremor and low frequency earthquakes have also occurred. Within the Katmai group of volcanoes, earthquakes are typically clustered in three regions: under Trident Volcano, under Mount Katmai to the east, and under Martin and Mageik volcanoes to the west. The current period of seismic unrest is most prominent in the area under Trident, but the rate of earthquakes has also increased in the region beneath Martin and Mageik volcanoes. Because of the initial sequence of deep earthquakes and continued episodes of tremor under Trident, it is most likely, though not certain, that the unrest observed in the area is due to movement of magma or magmatic fluids at depth there. There is no indication that an eruption of Trident is imminent, or that one will occur. Increases in seismic activity have been detected previously at Trident and other similar volcanoes, with no subsequent eruptions. We expect additional shallow seismicity and other signs of unrest, such as gas emissions, elevated surface temperatures, and surface deformation to precede any future eruption, if one were to occur. Should activity increase, AVO will issue further notices. AVO monitors Trident with a local network of seismometers, a webcam, remote sensing data, and regional infrasound and lightning networks. To view current monitoring data, see https://avo.alaska.edu/activity/Trident.php |
| (12) Volcanic cloud height: | none |
| (13) Other volcanic cloud information: | none |
| (14) Remarks: | Trident Volcano is one of the Katmai group of volcanoes located within Katmai National Park and Preserve on the Alaska Peninsula. Trident consists of a complex of four cones and numerous lava domes, all andesite and dacite in composition, that reach as high as 6,115 ft above sea level. An eruption beginning in 1953 constructed the newest cone, Southwest Trident, and four lava flows on the flank of the older complex. This eruption continued through 1974 and produced ash (an initial plume rose to 30,000 ft asl), bombs, and lava at various times. Fumaroles remain active on the summit of Southwest Trident and on the southeast flank of the oldest, central cone. Trident is located 148 km (92 miles) southeast of King Salmon and 440 km (273 miles) southwest of Anchorage. |
| (15) Contacts: | Michelle Coombs, Scientist-in-Charge, USGS mcoombs@usgs.gov (907) 786-7497 Társilo Girona, Acting Coordinating Scientist, UAFGI tarsilo.girona@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. |
| (1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA) | |
| (2) Issued: | (20230222/1847Z) |
| (3) Volcano: | Semisopochnoi (VNUM #311060) |
| (4) Current Color Code: | YELLOW |
| (5) Previous Color Code: | ORANGE |
| (6) Source: | Alaska Volcano Observatory |
| (7) Notice Number: | 2023/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: |
Although the active north cone of Mount Young continues to produce a robust steam plume, no ash emissions or explosive activity have been detected at Semisopochnoi volcano since late January. The level of seismic activity has also decreased, with no significant seismic tremor observed since January 25th. Thus, we are lowering the Aviation Color Code to YELLOW and Volcano Alert Level to ADVISORY. Small eruptions producing minor ash deposits within the vicinity of the active north crater of Mount Young, and ash clouds usually under 10,000 ft (3 km) above sea level, have characterized the recent activity at Semisopochnoi. More ash-producing events could occur again with little warning. Semisopochnoi is monitored by a local seismic and infrasound network, local web cameras, regional lightning and infrasound sensors, and satellite data. |
| (12) Volcanic cloud height: | none |
| (13) Other volcanic cloud information: | Steam only |
| (14) Remarks: | Remote Semisopochnoi volcano occupies the largest, young volcanic island in the western Aleutians. The uninhabited island is part of the Alaska Maritime National Wildlife Refuge. It is located 65 km (40 mi) northeast of Amchitka Island and 200 km (130 mi) west of Adak, Alaska. Semisopochnoi volcano is dominated by an 8-km (5-mile) 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. The north cone of Mount Young, in the southwest part of the caldera, is the site of the current eruption, which began in 2018. The last known eruption prior to 2018 was in 1987 from Sugarloaf Peak on the south coast of the island. |
| (15) Contacts: | Michelle Coombs, Scientist-in-Charge, USGS mcoombs@usgs.gov (907) 786-7497 Társilo Girona, Acting Coordinating Scientist, UAFGI tarsilo.girona@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. |
| (1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA) | |
| (2) Issued: | (20230119/2051Z) |
| (3) Volcano: | Pavlof (VNUM #312030) |
| (4) Current Color Code: | GREEN |
| (5) Previous Color Code: | YELLOW |
| (6) Source: | Alaska Volcano Observatory |
| (7) Notice Number: | 2023/A84 |
| (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: |
Eruptive activity at Pavlof Volcano has stopped. Seismicity has decreased to background levels, and no explosions have been detected since December 11, 2022. Weakly elevated surface temperatures and minor steaming from the recently active vent continue to be observed intermittently in satellite and web camera imagery, consistent with cooling of previously erupted lava. Due to the decrease in activity to background levels, we are lowering the Aviation Color Code to Green and the Volcano Alert Level to Normal. Previous eruptions of Pavlof indicate that the level of unrest can change quickly and eruptive activity could resume with little or no warning. Pavlof is monitored by local seismic and infrasound sensors, satellite data, web cameras, and regional infrasound and lightning networks. |
| (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) 378-5460 |
| (16) Next Notice: | |
| (1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA) | |
| (2) Issued: | (20230106/1815Z) |
| (3) Volcano: | Kilauea (VNUM #332010) |
| (4) Current Color Code: | ORANGE |
| (5) Previous Color Code: | RED |
| (6) Source: | Hawaiian Volcano Observatory |
| (7) Notice Number: | 2023/H16 |
| (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’s summit eruption continues and is 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 from WARNING to WATCH because the initial high effusion rates are declining, and no infrastructure is threatened. HVO is lowering Kīlauea’s aviation color code from RED to ORANGE because there is currently no threat of significant volcanic ash emission into the atmosphere outside of the hazardous closed area within Hawai‘i Volcanoes National Park. Hazards associated with the eruption are limited and are described below. HVO will continue to monitor this activity closely and report any significant changes in future notices.
|
| (12) Volcanic cloud height: | N/A |
| (13) Other volcanic cloud information: | N/A |
| (14) Remarks: | Kīlauea volcano began erupting within Halema‘uma‘u crater at approximately 4:34 p.m. HST on January 5, 2023, following a couple weeks of intermittently elevated summit earthquake activity and gradual inflationary summit ground tilt. Earthquake activity increased dramatically at approximately 3 p.m. on January 5 with increased rates of inflationary ground deformation, prompting HVO to raise Kīlauea’s alert level and aviation color code to WATCH/ORANGE and then to WARNING/RED after the eruption began. As of 7:30 a.m. HST this morning, January 6, several very minor fountains remain active in the central eastern portion of Halema‘uma‘u crater floor. The high initial effusion rates are declining rapidly as lava stored within the magma system over the past month is erupted. The fountains decreased in vigor overnight and are consistently about 5 meters (16 feet) high this morning. Lava flows have inundated much of the crater floor (which is nearly 300 acres or 120 hectares). The higher-elevation island that formed during the initial phase of the December 2020 eruption remains exposed, as well as a ring of older lava around the lava lake that was active prior to December 2022. This older lake has refilled from below with new lava. This morning, the depth of new lava remains at about 10 meters (32 feet) at the base of Halema‘uma‘u crater. Summit tilt switched from inflation to deflation around 5 p.m. HST yesterday, January 5, and that trend continues this morning. Following the eruption onset, summit earthquake activity greatly diminished and eruptive tremor (a signal associated with fluid movement) resumed. Volcanic gas emissions in the eruption area are elevated. Hazard Analysis: The 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/. |
| (15) Contacts: | |
| (16) Next Notice: | Kīlauea updates will be issued daily. Should volcanic activity change significantly a new VAN will be issued. Regularly scheduled updates are posted on the HVO website at https://www.usgs.gov/volcanoes/kilauea/volcano-updates More Information:
|
| (1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA) | |
| (2) Issued: | (20230106/0235Z) |
| (3) Volcano: | Kilauea (VNUM #332010) |
| (4) Current Color Code: | RED |
| (5) Previous Color Code: | ORANGE |
| (6) Source: | Hawaiian Volcano Observatory |
| (7) Notice Number: | 2023/H15 |
| (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 4:34 p.m. HST on January 5, 2023, the USGS Hawaiian Volcano Observatory detected glow in Kīlauea summit webcam images indicating that the eruption has resumed within Halemaʻumaʻu crater in Kīlauea’s summit caldera, within Hawai‘i Volcanoes National Park. The opening phases of eruptions are dynamic. Webcam imagery shows fissures at the base of Halemaʻumaʻu crater generating lava flows on the surface of the crater floor. The activity is confined to Halemaʻumaʻu and the hazards will be reassessed as the eruption progresses. HVO will continue to monitor this activity closely and report any significant changes in future notices.
|
| (12) Volcanic cloud height: | N/A |
| (13) Other volcanic cloud information: | N/A |
| (14) Remarks: | Hazard Analysis: The 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/. |
| (15) Contacts: | |
| (16) Next Notice: | Kīlauea updates will be issued daily. Should volcanic activity change significantly a new VAN will be issued. Regularly scheduled updates are posted on the HVO website at https://www.usgs.gov/volcanoes/kilauea/volcano-updates More Information:
|
| (1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA) | |
| (2) Issued: | (20230106/0120Z) |
| (3) Volcano: | Kilauea (VNUM #332010) |
| (4) Current Color Code: | ORANGE |
| (5) Previous Color Code: | YELLOW |
| (6) Source: | Hawaiian Volcano Observatory |
| (7) Notice Number: | 2022/H660 |
| (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 in the early morning of January 5, 2023, 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. However, an eruption in Kīlauea’s summit region, within Hawai‘i Volcanoes National Park and away from infrastructure, is one potential outcome.
|
| (12) Volcanic cloud height: | N/A |
| (13) Other volcanic cloud information: | N/A |
| (14) Remarks: | For discussion of Kīlauea hazards, please see: https://www.usgs.gov/observatories/hawaiian-volcano-observatory/hazards. |
| (15) Contacts: | |
| (16) Next Notice: | Kīlauea updates will now be issued daily. Should volcanic activity change significantly a new VAN will be issued. Regularly scheduled updates are posted on the HVO website at https://www.usgs.gov/volcanoes/kilauea/volcano-updates More Information:
|
| (1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA) | |
| (2) Issued: | (20230105/2009Z) |
| (3) Volcano: | Cleveland (VNUM #311240) |
| (4) Current Color Code: | UNASSIGNED |
| (5) Previous Color Code: | YELLOW |
| (6) Source: | Alaska Volcano Observatory |
| (7) Notice Number: | 2023/A21 |
| (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 reduction of 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 surface temperatures and sulfur dioxide emissions prompted raising the Aviation Color Code and Volcano Alert Level from UNASSIGNED/UNASSIGNED to YELLOW/ADVISORY on May 11, 2022. This activity continued throughout the summer, but all signs of unrest have ceased or declined in recent months. Elevated surface temperatures in the summit crater are occasionally being observed but at reduced frequency and strength. Sulfur dioxide emissions have not been detected in satellite data since July 29, 2022. The last eruptive activity at Cleveland volcano was a short-lived explosion on the evening (local time) of June 1, 2020. 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 Pavel Izbekov, Acting Coordinating Scientist, UAFGI peizbekov@alaska.edu (907) 322-4085 |
| (16) Next Notice: | |
| (1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA) | |
| (2) Issued: | (20221228/2046Z) |
| (3) Volcano: | Semisopochnoi (VNUM #311060) |
| (4) Current Color Code: | ORANGE |
| (5) Previous Color Code: | YELLOW |
| (6) Source: | Alaska Volcano Observatory |
| (7) Notice Number: | 2022/A1518 |
| (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 resumed over the past 24 hours at the active north crater of Mount Cerberus. Minor ash deposits on the flanks of Mount Cerberus were observed on fresh snow extending up to ~1 km (~1000 yards) from the vent in web camera images over the past day. No ash plumes have been observed in web camera or satellite imagery, but a persistent steam plume rising up to 5,000 ft above sea level from the active crater may now be carrying minor volcanic ash within it. The observation of ash deposits follows increased seismicity, including seismic tremor, in the past week. This activity is similar to eruptive activity observed over the past year at Semisopochnoi, but not since November 7. The Alaska Volcano Observatory is therefore raising the Aviation Color Code to ORANGE and Volcano Alert Level to WATCH. Small eruptions producing minor ash deposits within the vicinity of the active north crater of Mount Cerberus and ash clouds usually under 10,000 ft (3 km) above sea level have characterized the recent activity and more ash-producing events could occur again with little warning. Semisopochnoi is monitored by a local seismic and infrasound network, local web cameras, regional lightning and infrasound sensors, and satellite data. |
| (12) Volcanic cloud height: | <5,000 ft |
| (13) Other volcanic cloud information: | steam and minor ash |
| (14) Remarks: | Remote Semisopochnoi volcano occupies the largest, young volcanic island in the western Aleutians. The uninhabited island is part of the Alaska Maritime National Wildlife Refuge. It is located 65 km (40 mi) northeast of Amchitka Island and 200 km (130 mi) west of Adak, Alaska. Semisopochnoi volcano is dominated by an 8-km (5-mile) 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. The north cone of Mount Cerberus, in the southwest part of the caldera, is the site of the current eruption, which began in 2018. The last known eruption prior to 2018 was in 1987 from Sugarloaf Peak on the south coast of the island. |
| (15) Contacts: | Michelle Coombs, Scientist-in-Charge, USGS, mcoombs@usgs.gov, (907) 786-7497 David Fee, Coordinating Scientist, UAFGI dfee1@alaska.edu (907) 378-5460 |
| (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. |
| (1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA) | |
| (2) Issued: | (20221217/2033Z) |
| (3) Volcano: | Pavlof (VNUM #312030) |
| (4) Current Color Code: | YELLOW |
| (5) Previous Color Code: | ORANGE |
| (6) Source: | Alaska Volcano Observatory |
| (7) Notice Number: | 2022/A1462 |
| (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: |
Eruptive activity at Pavlof Volcano has paused. Although seismicity remains above background levels with intermittent seismic tremor, no explosions have been detected since December 7, 2022. No elevated surface temperatures or incandescent lava have been observed in satellite and webcam images since December 2. Due to this decrease in activity, we are lowering the Aviation Color Code to YELLOW and Volcano Alert Level to ADVISORY. Previous eruptions of Pavlof indicate that the level of unrest can change quickly and eruptive activity could resume with little or no warning. Pavlof is monitored by local seismic and infrasound sensors, satellite data, web cameras, and regional infrasound and lightning networks. |
| (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) 378-5460 |
| (16) Next Notice: | |
| (1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA) | |
| (2) Issued: | (20221213/1717Z) |
| (3) Volcano: | Mauna Loa (VNUM #332020) |
| (4) Current Color Code: | YELLOW |
| (5) Previous Color Code: | ORANGE |
| (6) Source: | Hawaiian Volcano Observatory |
| (7) Notice Number: | 2022/H657 |
| (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: |
Mauna Loa is no longer erupting. Lava supply to the fissure 3 vent on the Northeast Rift Zone ceased on December 10 and sulfur dioxide emissions have decreased to near pre-eruption background levels. Volcanic tremor and earthquakes associated with the eruption are greatly diminished. 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. Spots of incandescence may remain near the vent, along channels, and at the flow front for days or weeks as the lava flows cool. However, eruptive activity is not expected to return based on past eruptive behavior. Summit and Northeast Rift Zone inflation continues. For more information about the meaning of aviation color codes, see https://www.usgs.gov/programs/VHP/volcanic-alert-levels-characterize-conditions-us-volcanoes |
| (12) Volcanic cloud height: | N/A |
| (13) Other volcanic cloud information: | N/A |
| (14) Remarks: | Continuing hazards A vent on the west side of the fissure 3 cone remains incandescent and occasionally produces small explosions as trapped gases are released. The lava flows around the vent remain hot and unstable. The vent area is also cut by numerous ground cracks. Hawai‘i Volcanoes National Park has closed the Mauna Loa Road from Kīpukapuaulu and the closure extends to the summit caldera; for more information please see https://www.nps.gov/havo/index.htm.
|
| (15) Contacts: | |
| (16) Next Notice: | Mauna Loa updates will be issued daily until December 15, after which they will be issued weekly on Thursdays. Should volcanic activity change significantly a new VAN will be issued. Regularly scheduled updates on the status of Mauna Loa will be posted on the HVO website at https://www.usgs.gov/volcanoes/mauna-loa/volcano-updates More Information:
|
| (1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA) | |
| (2) Issued: | (20221213/1712Z) |
| (3) Volcano: | Kilauea (VNUM #332010) |
| (4) Current Color Code: | YELLOW |
| (5) Previous Color Code: | ORANGE |
| (6) Source: | Hawaiian Volcano Observatory |
| (7) Notice Number: | 2022/H656 |
| (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 is no longer erupting. Lava supply to the Halemaʻumaʻu lava lake ceased on December 9 based upon lava lake levels and behavior of the crater floor. 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. Seismicity and deformation patterns remain unsettled. Potential remains for resumption of this eruption or initiation of a new eruption at or near the summit of Kīlauea. Hazards are still present on Kīlauea and are described below. Residents and visitors should stay informed and follow County of Hawai‘i and Hawaiʻi Volcanoes National Park guidelines. For more information about the meaning of aviation color codes, see https://www.usgs.gov/programs/VHP/volcanic-alert-levels-characterize-conditions-us-volcanoes
|
| (12) Volcanic cloud height: | N/A |
| (13) Other volcanic cloud information: | N/A |
| (14) Remarks: | 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 notice odors of these gases occasionally. 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. Please see the Hawaiʻi Volcanoes National Park website for visitor information: https://www.nps.gov/havo/index.htm. |
| (15) Contacts: | |
| (16) Next Notice: | Kīlauea updates will now be issued weekly on Tuesdays. Should volcanic activity change significantly a new VAN will be issued. Regularly scheduled updates are posted on the HVO website at https://www.usgs.gov/volcanoes/kilauea/volcano-updates More Information:
|
| (1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA) | |
| (2) Issued: | (20221204/1810Z) |
| (3) Volcano: | Mauna Loa (VNUM #332020) |
| (4) Current Color Code: | ORANGE |
| (5) Previous Color Code: | RED |
| (6) Source: | Hawaiian Volcano Observatory |
| (7) Notice Number: | 2022/H628 |
| (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: |
Lava eruption from fissure 3 on the Northeast Rift Zone of Mauna Loa continues, but the threat to aviation of significant volcanic ash emission into the atmosphere has passed. For this reason, HVO is reducing the aviation color code from RED to ORANGE. The ground-based volcano alert level will remain at WARNING, reflecting the ongoing hazards of the fissure 3 lava flow. Lava flows are slowly moving north toward Daniel K. Inouye Highway and are spreading out and inflating (thickening) as they advance over low-sloping ground. The fronts of lava flows can break open unexpectedly, sending flows in several directions. Rain on lava creates steam and reduces visibility. If visiting the County of Hawai'i public viewing area, remain with your vehicle and do not approach the flows. The Federal Aviation Administration has issued a temporary flight restriction extending from the surface to 1500 feet (457 meters) above ground level in the eruption area. See: https://tfr.faa.gov/save_pages/detail_2_9210.html For more information about the meaning of aviation color codes, see https://www.usgs.gov/programs/VHP/volcanic-alert-levels-characterize-conditions-us-volcanoes |
| (12) Volcanic cloud height: | N/A |
| (13) Other volcanic cloud information: | N/A |
| (14) Remarks: | The eruption has now focused at a single vent, fissure 3, at an elevation of 11,500 ft (3510 m) along the Northeast Rift Zone of Mauna Loa. Lava fountaining at the vent has been approximately 100 feet (33 m) tall over the past day, depositing fragments of volcanic material in the area near the vent. Pele's hair (small strands of volcanic glass) are being wafted great distances and have been reported as far as Laupāhoehoe, a community on the northeast coastline of the Island of Hawai'i about 23 miles (37 km) north of Hilo and 37 mi (59 km) northwest of fissure 3. Sulfur dioxide (SO2) emission rates of approximately 180,000 tonnes per day (t/d) were measured on December 1, 2022 and remain elevated at this time. Volcanic gas is rising high and vertically into the atmosphere before being blown to the west at high altitude, generating vog (volcanic air pollution) in areas downwind. The International Volcanic Health Hazard Network has detailed information about vog: https://vog.ivhhn.org/. Forecasts for the dispersion of vog can be found on the Vog Forecasting Dashboard: http://weather.hawaii.edu/vmap/new/ Fissure 3 is generating a lava flow traveling to the north toward the Daniel K. Inouye Highway (Saddle Road) that has reached flatter ground and slowed down significantly over the past several days, as expected. As of 7 a.m. today, December 4, the flow front was about 2.3 mi (3.6 km) from the Daniel K. Inouye Highway (Saddle Road). During the past 24 hours, the lava flow advanced at an average rate of about 40 feet per hour (12 meters per hour). Though the advance rate has slowed over the past several days, the lava flow remains active with a continuous supply from the fissure 3 vent. Advance rates may be highly variable over the coming days and weeks. On the flat ground between Mauna Loa and Mauna Kea, lava flows advance more slowly, spread out, and inflate. Individual lobes may advance quickly, and then stall. Additional breakouts may occur if lava channels get blocked upslope. There are many variables at play and both the direction and timing of flow advances are expected to change over periods of hours to days, making it difficult to estimate when or if the flow will impact Daniel K. Inouye Highway. Tremor (a signal associated with subsurface fluid movement) continues beneath the currently active fissures. This indicates that magma is still being supplied to the fissure, and activity is likely to continue as long as we see this signal. There is no active lava within Moku'āweoweo caldera nor the Southwest Rift Zone. We do not expect any eruptive activity outside the Northeast Rift Zone. Most recent eruption map: https://www.usgs.gov/maps/december-3-2022-mauna-loa-eruption-map Information on lava viewing: https://www.khon2.com/local-news/mauna-loa-eruption/new-4-5-mile-route-opened-to-view-mauna-loa-eruption/ Volcanic Hazards: Air quality/volcanic gas plume (fissure eruption): High levels of volcanic gas, including sulfur dioxide (SO2), are emitted from the fissure vents. As SO2 is released from the 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 downwind. The particles scatter sunlight and cause the visible haze, known as vog (volcanic air pollution, from “volcanic smog”). Vog creates the potential for airborne health hazards to residents and visitors, damages agricultural crops and other plants, and affects livestock operations. Lava flows: Hawaiian lava flows generally advance slowly enough that people can avoid them. They can destroy everything in their paths, including vegetation and infrastructure—which can cut off road access and utilities. Hazards associated with active or recent lava flows include hot and glassy (sharp) surfaces that can cause severe burns, abrasions, and lacerations upon contact with unprotected or exposed skin; uneven and rough terrain can lead to falls and other injuries; hot temperatures that can cause heat exhaustion or dehydration, or in heavy rain can produce steamy ground-fog that can be acidic, severely limiting visibility and sometimes causing difficulty breathing. Tephra fall: Pele's hair and other lightweight volcanic glass fragments from lava fountains and spattering will fall downwind, dusting the ground within a few hundred meters (yards) of the vent. High winds may waft lighter particles and transport them greater distances downwind. Residents are urged to minimize exposure to these volcanic particles, which can cause skin and eye irritation similar to volcanic ash. Secondary hazards: Lava flow advance into vegetated areas may generate secondary hazards by igniting small fires in vegetation adjacent to lava flow margins. Lava flows that cover and burn vegetation and soil also introduce the hazard of subsurface natural gas pockets igniting, which can cause methane explosions. These explosions can blast lava fragments up to several meters (yards) away and can be hazardous to observers. Residents with questions about emergency response and resources that may be available to assist those at risk should consult https://www.hawaiicounty.gov/departments/civil-defense/active-civil-defense-alerts-and-maps. Hawai‘i Volcanoes National Park has closed the Mauna Loa Road from Kīpukapuaulu and the closure extends to the summit caldera; for more information please see https://www.nps.gov/havo/index.htm.
|
| (15) Contacts: | |
| (16) Next Notice: | Updates on the status of Mauna Loa activity will be posted on the HVO web site in the morning and afternoon at: https://www.usgs.gov/volcanoes/mauna-loa/volcano-updates You can receive these updates via email by subscribing to the free Volcano Notification Service at: http://volcanoes.usgs.gov/vns/. Questions can be emailed to askHVO@usgs.gov. More Information:
|
| (1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA) | |
| (2) Issued: | (20221128/2254Z) |
| (3) Volcano: | Ahyi Seamount (VNUM #284141) |
| (4) Current Color Code: | YELLOW |
| (5) Previous Color Code: | UNASSIGNED |
| (6) Source: | U.S. Geological Survey |
| (7) Notice Number: | 2022/N50 |
| (8) Volcano Location: | N 20 deg 25 min E 145 deg 1 min |
| (9) Area: | Northern Mariana Islands |
| (10) Summit Elevation: | -449 ft (-137 m) |
| (11) Volcanic Activity Summary: |
Signs of unrest at Ahyi Seamount have been observed in satellite and remote geophysical data. A plume of discolored water above Ahyi Seamount has been visible persistently in satellite data since November 18, 2022. This discoloration could be due to degassing or eruption at the volcano, but we cannot say for certain due to a lack of local monitoring stations. Starting in mid-October, hydroacoustic sensors at Wake Island, 2,270 km (1,410 miles) east of Ahyi, began recording signals consistent with activity from an undersea volcanic source. In collaboration with the Laboratoire de Geophysique in Tahiti, recent combined analysis of the hydroacoustic signals together with data from seismic stations located at Guam and Chichijima Island, Japan, confirm that the source of this activity is at or near Ahyi seamount. Hydrophone signals continue to be observed but have decreased in the past few weeks. Due to the current activity, the aviation color code is being raised from UNASSIGNED to YELLOW and the alert level is being raised from UNASSIGNED to ADVISORY. |
| (12) Volcanic cloud height: | No volcanic cloud produced |
| (13) Other volcanic cloud information: | Water discoloration observed above seamount in satellite images |
| (14) Remarks: | Ahyi seamount is a large conical submarine volcano that rises to within 137 m (450 ft) of the sea surface about 18 km (11 mi) southeast of Farallon de Pajaros (Uracas) Island in the northern Marianas, about 600 km (370 mi) north of the island of Saipan. In the past, discolored water has been observed over the submarine volcano. In 1979, the crew of a fishing boat felt shocks over the summit area and then observed upwelling of sulfur-bearing water. On April 24-25, 2001 an explosive submarine eruption was detected seismically from a seismic station on Rangiroa Atoll, Tuamotu Archipelago. The event was well constrained (+/- 15 km or 9 miles) at a location near the southern base of Ahyi. |
| (15) Contacts: | CNMI Homeland Security and Emergency Management |
| (16) Next Notice: | A new VAN will be issued if conditions change significantly or alert levels are modified. |
| (1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA) | |
| (2) Issued: | (20221128/1720Z) |
| (3) Volcano: | Mauna Loa (VNUM #332020) |
| (4) Current Color Code: | RED |
| (5) Previous Color Code: | RED |
| (6) Source: | Hawaiian Volcano Observatory |
| (7) Notice Number: | 2022/H603 |
| (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: |
The eruption of Mauna Loa has migrated from the summit to the Northeast Rift Zone where fissures are feeding several lava flows. HVO staff on an overflight at approximately 6:30 a.m. HST confirmed fissures at high elevations within Hawai‘i Volcanoes National Park are feeding lava flows upslope of the Mauna Loa Weather Observatory. Lava flows are not threatening any downslope communities and all indications are that the eruption will remain in the Northeast Rift Zone. Volcanic gas and possibly fine ash and Pele's Hair may be carried downwind. Residents at risk from Mauna Loa lava flows should review preparedness and refer to Hawai‘i County Civil Defense information for further guidance. Based on past events, the early stages of a Mauna Loa rift zone eruption can be very dynamic, and the location and advance of lava flows can change rapidly. HVO is in close consultation with emergency management partners and will monitor the volcano closely to provide further updates on activity. |
| (12) Volcanic cloud height: | N/A |
| (13) Other volcanic cloud information: | N/A |
| (14) Remarks: | Residents with questions about emergency response and resources that may be available to assist those at risk should consult https://www.hawaiicounty.gov/departments/civil-defense/active-civil-defense-alerts-and-maps. Hawai‘i Volcanoes National Park has closed the Mauna Loa Road from Kīpukapuaulu and the closure extends to the summit caldera; for more information please see https://www.nps.gov/havo/index.htm. Vog information can be found at https://vog.ivhhn.org/. Background: Since the mid-19th century, Mauna Loa’s Northeast Rift Zone has erupted eight times: in 1843, 1852, 1855–1856, 1880–1881, 1899, 1935–1936, 1942, and 1984. Lava flows from the Northeast Rift Zone can travel in north, west, northwest, south, and southwest directions. |
| (15) Contacts: | |
| (16) Next Notice: | Updates on the status of Mauna Loa activity will be posted on the HVO web site at: https://www.usgs.gov/volcanoes/mauna-loa/volcano-updates You can receive these updates via email by subscribing to the free Volcano Notification Service at: http://volcanoes.usgs.gov/vns/. Questions can be emailed to askHVO@usgs.gov. |
| (1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA) | |
| (2) Issued: | (20221128/0945Z) |
| (3) Volcano: | Mauna Loa (VNUM #332020) |
| (4) Current Color Code: | RED |
| (5) Previous Color Code: | YELLOW |
| (6) Source: | Hawaiian Volcano Observatory |
| (7) Notice Number: | 2022/H602 |
| (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: |
At approximately 11:30 p.m. HST this evening, November 27, an eruption began in Moku‘āweoweo, the summit caldera of Mauna Loa, inside Hawai‘i Volcanoes National Park. At this time, lava flows are contained within the summit area and are not threatening downslope communities. Winds may carry volcanic gas and possibly fine ash and Pele’s hair downwind. Residents at risk from Mauna Loa lava flows should review preparedness and refer to Hawai‘i County Civil Defense information for further guidance. Based on past events, the early stages of a Mauna Loa eruption can be very dynamic and the location and advance of lava flows can change rapidly. If the eruption remains in Moku‘āweoweo, lava flows will most likely be confined within the caldera walls. However, if the eruptive vents migrate outside its walls, lava flows may move rapidly downslope. HVO is in close consultation with emergency management partners and will be monitoring the volcano closely to provide further updates on activity. As soon as possible, HVO will conduct aerial reconnaissance to better describe the eruption and assess hazards. |
| (12) Volcanic cloud height: | N/A |
| (13) Other volcanic cloud information: | N/A |
| (14) Remarks: | Remarks: Residents with questions about emergency response and resources that may be available to assist those at risk should consult https://www.hawaiicounty.gov/departments/civil-defense/active-civil-defense-alerts-and-maps. Hawai‘i Volcanoes National Park has closed the Mauna Loa summit area to visitors; for more information please see https://www.nps.gov/havo/index.htm. Vog information can be found at https://vog.ivhhn.org/. |
| (15) Contacts: | |
| (16) Next Notice: | HVO Daily Updates on the status of Mauna Loa activity will be posted on the HVO web site at: https://www.usgs.gov/volcanoes/mauna-loa/volcano-updates You can receive these updates via email by subscribing to the free Volcano Notification Service at: http://volcanoes.usgs.gov/vns/. Questions can be emailed to askHVO@usgs.gov. |
| (1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA) | |
| (2) Issued: | (20221123/2130Z) |
| (3) Volcano: | Semisopochnoi (VNUM #311060) |
| (4) Current Color Code: | YELLOW |
| (5) Previous Color Code: | ORANGE |
| (6) Source: | Alaska Volcano Observatory |
| (7) Notice Number: | 2022/A1337 |
| (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: |
Although the active north cone of Mount Cerberus continues to produce a vapor plume and elevated seismicity, no ash emissions or explosive activity have been detected at Semisopochnoi volcano since November 7th. The level of seismic activity is still elevated but has decreased. Thus, we are lowering the Aviation Color Code to YELLOW and Volcano Alert Level to ADVISORY. Small eruptions producing minor ash deposits within the vicinity of the active north crater of Mount Cerberus and ash clouds usually under 10,000 ft (3 km) above sea level have characterized the recent activity and more ash-producing events could occur again with little warning. Semisopochnoi is monitored by a local seismic and infrasound network, local web cameras, regional lightning and infrasound sensors, and satellite data. |
| (12) Volcanic cloud height: | none |
| (13) Other volcanic cloud information: | none |
| (14) Remarks: | Remote Semisopochnoi volcano occupies the largest, young volcanic island in the western Aleutians. The uninhabited island is part of the Alaska Maritime National Wildlife Refuge. It is located 65 km (40 mi) northeast of Amchitka Island and 200 km (130 mi) west of Adak, Alaska. Semisopochnoi volcano is dominated by an 8-km (5-mile) 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. The north cone of Mount Cerberus, in the southwest part of the caldera, is the site of the current eruption, which began in 2018. The last known eruption prior to 2018 was in 1987 from Sugarloaf Peak on the south coast of the island. |
| (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. |
| (1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA) | |
| (2) Issued: | (20221119/0134Z) |
| (3) Volcano: | Takawangha (VNUM #311090) |
| (4) Current Color Code: | YELLOW |
| (5) Previous Color Code: | GREEN |
| (6) Source: | Alaska Volcano Observatory |
| (7) Notice Number: | 2022/A1315 |
| (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 number of small earthquakes detected near Takawangha volcano has increased over the past few days and has intensified over the past 24 hours. The earthquakes, the largest with magnitudes between 2 and 3, have preliminary depths of about 2 to 4 miles (3 to 6 km) below sea level. This activity may be due to the movement of magma beneath the volcano. It marks a departure from background activity and therefore AVO is raising the Aviation Color Code to YELLOW and Alert Level to ADVISORY for Takawangha volcano. No eruptive activity has been detected in satellite or other monitoring data. Takawangha is monitored with a local seismic network, a single local infrasound sensor, regional infrasound and lightning sensors, and satellite imagery. |
| (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 David Fee, Coordinating Scientist, UAFGI, dfee1@alaska.edu, (907) 378-5460 |
| (16) Next Notice: | |
| (1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA) | |
| (2) Issued: | (20221107/2208Z) |
| (3) Volcano: | Semisopochnoi (VNUM #311060) |
| (4) Current Color Code: | ORANGE |
| (5) Previous Color Code: | YELLOW |
| (6) Source: | Alaska Volcano Observatory |
| (7) Notice Number: | 2022/A1242 |
| (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: |
Small explosions have been detected in geophysical data over the past week from the north crater of Mount Cerberus at Semisopochnoi. In addition, volcanic tremor has resumed during the same time period. Ash emissions have not been observed. However, the type of unrest we detected was associated with ash emissions during previous periods of unrest and, if occurring, such ash emissions are likely below 10,000 ft above sea level. These events are similar to eruptive activity observed over the last year at Semisopochnoi, but not since September 14. The Aviation Color Code and Volcano Alert Level are being raised to ORANGE/WATCH. Small eruptions producing minor ash deposits within the vicinity of the active north crater of Mount Cerberus and ash clouds usually under 10,000 ft (3 km) above sea level have characterized the recent activity and more ash-producing events could occur again with little warning. Semisopochnoi is monitored by a local seismic and infrasound network, local web cameras, regional lightning and infrasound sensors, and satellite data. |
| (12) Volcanic cloud height: | less than 10,000 ft. above sea level |
| (13) Other volcanic cloud information: | none |
| (14) Remarks: | Remote Semisopochnoi volcano occupies the largest, young volcanic island in the western Aleutians. The uninhabited island is part of the Alaska Maritime National Wildlife Refuge. It is located 65 km (40 mi) northeast of Amchitka Island and 200 km (130 mi) west of Adak, Alaska. Semisopochnoi volcano is dominated by an 8-km (5-mile) 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. The north cone of Mount Cerberus, in the southwest part of the caldera, is the site of the current eruption, which began in 2018. The last known eruption prior to 2018 was in 1987 from Sugarloaf Peak on the south coast of the island. |
| (15) Contacts: | Kristi Wallace, Acting Scientist-in-Charge, USGS, kwallace@usgs.gov, (907) 786-7497 David Fee, Coordinating Scientist, UAFGI, dfee1@alaska.edu, (907) 378-5460 |
| (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. |
| (1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA) | |
| (2) Issued: | (20221019/2206Z) |
| (3) Volcano: | Trident (VNUM #312160) |
| (4) Current Color Code: | GREEN |
| (5) Previous Color Code: | YELLOW |
| (6) Source: | Alaska Volcano Observatory |
| (7) Notice Number: | 2022/A1190 |
| (8) Volcano Location: | N 58 deg 14 min W 155 deg 6 min |
| (9) Area: | Alaska Peninsula |
| (10) Summit Elevation: | 3599 ft (1097 m) |
| (11) Volcanic Activity Summary: |
The swarm of earthquakes that began on August 24, 2022, beneath Trident Volcano has subsided and seismic tremor has not been observed since September 30, 2022. Occasional local earthquakes continue to be detected at background levels. Due to this decrease in activity and the absence of other signs of unrest, we are lowering the Aviation Color Code to GREEN and the Volcano Alert level to NORMAL. Should activity increase, AVO will issue further notices. AVO monitors Trident with a local network of seismometers, a webcam, remote sensing data, and regional infrasound and lightning networks. To view current monitoring data, see https://avo.alaska.edu/activity/Trident.php |
| (12) Volcanic cloud height: | none |
| (13) Other volcanic cloud information: | none |
| (14) Remarks: | Trident Volcano is one of the Katmai group of volcanoes located within Katmai National Park and Preserve on the Alaska Peninsula. Trident consists of a complex of four cones and numerous lava domes, all andesite and dacite in composition, that reach as high as 6,115 ft above sea level. An eruption beginning in 1953 constructed the newest cone, Southwest Trident, and four lava flows on the flank of the older complex. This eruption continued through 1974 and produced ash (an initial plume rose to 30,000 ft asl), bombs, and lava at various times. Fumaroles remain active on the summit of Southwest Trident and on the southeast flank of the oldest, central cone. Trident is located 148 km (92 miles) southeast of King Salmon and 440 km (273 miles) southwest 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) 378-5460 |
| (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. |
| (1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA) | |
| (2) Issued: | (20220929/2257Z) |
| (3) Volcano: | Semisopochnoi (VNUM #311060) |
| (4) Current Color Code: | YELLOW |
| (5) Previous Color Code: | ORANGE |
| (6) Source: | Alaska Volcano Observatory |
| (7) Notice Number: | 2022/A1082 |
| (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: |
Although the active north cone of Mount Cerberus continues to produce a vapor plume and elevated seismic tremor, no ash emissions or explosive activity have been detected at Semisopochnoi volcano since September 14. The level of seismic activity is still elevated but has decreased. Thus, we are lowering the Aviation Color Code to YELLOW and Volcano Alert Level to ADVISORY. Small eruptions producing minor ash deposits within the vicinity of the active north crater of Mount Cerberus and ash clouds usually under 10,000 ft (3 km) above sea level have characterized the recent activity. More ash-producing events could occur again with little warning. Semisopochnoi is monitored by a local seismic and infrasound network, local web cameras, regional lightning and infrasound sensors, and satellite data. |
| (12) Volcanic cloud height: | none |
| (13) Other volcanic cloud information: | none |
| (14) Remarks: | Remote Semisopochnoi volcano occupies the largest, young volcanic island in the western Aleutians. The uninhabited island is part of the Alaska Maritime National Wildlife Refuge. It is located 65 km (40 mi) northeast of Amchitka Island and 200 km (130 mi) west of Adak, Alaska. Semisopochnoi volcano is dominated by an 8-km (5-mile) 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. The north cone of Mount Cerberus, in the southwest part of the caldera, is the site of the current eruption, which began in 2018. The last known eruption prior to 2018 was in 1987 from Sugarloaf Peak on the south coast of the island. |
| (15) Contacts: | Michelle Coombs, Scientist-in-Charge, USGS, mcoombs@usgs.gov, (907) 786-7497 David Fee, Coordinating Scientist, UAFGI, dfee1@alaska.edu, (907) 378-5460 |
| (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. |
| (1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA) | |
| (2) Issued: | (20220929/2256Z) |
| (3) Volcano: | Trident (VNUM #312160) |
| (4) Current Color Code: | YELLOW |
| (5) Previous Color Code: | GREEN |
| (6) Source: | Alaska Volcano Observatory |
| (7) Notice Number: | 2022/A1083 |
| (8) Volcano Location: | N 58 deg 14 min W 155 deg 6 min |
| (9) Area: | Alaska Peninsula |
| (10) Summit Elevation: | 3599 ft (1097 m) |
| (11) Volcanic Activity Summary: |
The swarm of earthquakes that began on August 24, 2022, beneath Trident volcano continues. In addition, episodes of weak seismic tremor and low frequency earthquakes have been detected since August 28. Together, these observations mean that Trident is exhibiting signs of elevated unrest above known background level. Therefore, we are raising the Aviation Color Code to YELLOW and the Volcano Alert level to ADVISORY. During the current swarm, earthquake depths were initially mostly deep at around 25 km (16 miles) below sea level but became progressively shallower to around 5 km (3 miles) by August 28. Since then, earthquakes have mostly occurred 3 to 6 km (about 2 to 4 miles) below sea level, although some deeper events have been detected. Earthquake magnitudes (M) have ranged from M –0.7 to M 1.9. At the peak of the swarm, dozens of earthquakes occurred daily beneath the volcano, but earthquake rates have since decreased to just a few per day. No other signs of unrest have been detected in monitoring data. The increase in seismic activity is likely caused by movement of magma or magmatic fluids. Increases in seismic activity have been detected previously at Trident and other similar volcanoes, with no subsequent eruptions. We expect additional shallow seismicity and other signs of unrest, such as gas emissions, elevated surface temperatures, and surface deformation to precede any future eruption, if one were to occur. Should activity increase, AVO will issue further notices. AVO monitors Trident with a local network of seismometers, a webcam, remote sensing data, and regional infrasound and lightning networks. To view current monitoring data, see https://avo.alaska.edu/activity/Trident.php |
| (12) Volcanic cloud height: | none |
| (13) Other volcanic cloud information: | none |
| (14) Remarks: | Trident is one of the Katmai group of volcanoes located within Katmai National Park and Preserve on the Alaska Peninsula. Trident consists of a complex of four cones and numerous lava domes, all andesite and dacite in composition, that reach as high as 6,115 ft above sea level. An eruption beginning in 1953 constructed the newest cone, Southwest Trident, and four lava flows on the flank of the older complex. This eruption continued through 1974 and produced ash (an initial plume rose to 30,000 ft asl), bombs, and lava at various times. Fumaroles remain active on the summit of Southwest Trident and on the southeast flank of the oldest, central cone. Trident is located 148 km (92 miles) southeast of King Salmon and 440 km (273 miles) southwest 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) 378-5460 |
| (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. |
| (1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA) | |
| (2) Issued: | (20220920/2040Z) |
| (3) Volcano: | Shishaldin (VNUM #311360) |
| (4) Current Color Code: | GREEN |
| (5) Previous Color Code: | UNASSIGNED |
| (6) Source: | Alaska Volcano Observatory |
| (7) Notice Number: | 2022/A1045 |
| (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 over the past year. 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, infrasound, GPS, and tilt stations, web camera images, remote infrasound and lightning networks, and satellite images. |
| (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, UAFGI, dfee1@alaska.edu, (907) 378-5460 |
| (16) Next Notice: | |
| (1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA) | |
| (2) Issued: | (20220827/0218Z) |
| (3) Volcano: | Ofu-Olosega (VNUM #244010) |
| (4) Current Color Code: | GREEN |
| (5) Previous Color Code: | YELLOW |
| (6) Source: | Hawaiian Volcano Observatory |
| (7) Notice Number: | 2022/H392 |
| (8) Volcano Location: | S 14 deg 10 min W 169 deg 37 min |
| (9) Area: | American Samoa |
| (10) Summit Elevation: | 2096 ft (639 m) |
| (11) Volcanic Activity Summary: |
Ofu-Olosega Islands volcano has been ruled out as the source of the ongoing Manuʻa Islands earthquake swarm. Data from seismometers installed in the Manuʻa Islands this week confirms that the ongoing earthquake activity is related to Taʻū Island volcano and not Ofu-Olosega. Accordingly, the USGS is lowering the volcano alert level to NORMAL and the aviation color code to GREEN for Ofu-Olosega. Taʻū Island remains at ADVISORY/YELLOW. Due to the closeness of the Ofu-Olosega Islands to Taʻū Island, residents of Ofu-Olosega could still be significantly affected by events that may take place on or around Taʻu Island. The earthquake swarm is still ongoing, and people on Ofu-Olosega are likely to feel shaking from future events. Residents of Ofu-Olosega can now find updates on relevant hazards and other important information in the Daily Reports for Taʻū Island. Possible hazards that could impact residents of Ofu-Olosega include shaking related to strong, damaging earthquakes, local tsunamis or large waves related to underwater volcanic activity or landslides, and/or ash and gas from volcanic eruptions. USGS scientists continue to monitor the earthquake swarm with six microseismometers placed on Tutuila, Taʻū, and Olosega Islands and two more sensitive seismometers on Taʻū and Ofu Islands. We are working to bring a third advanced seismometer online on eastern Ta’u Island. To keep receiving information about the ongoing earthquake crisis in American Samoa, subscribe to the Volcano Notification Service (https://volcanoes.usgs.gov/vns2/) Samoan and English language alert level and color code definitions: (PDF download, 57.68 kb) https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/media/files/VOLCANO%20AVIATION%20CODES%20AND%20ALERT%20LEVELS.pdf
|
| (12) Volcanic cloud height: | Unknown |
| (13) Other volcanic cloud information: | Unknown |
| (14) Remarks: | Hazards It is unclear if this earthquake swarm at Taʻū will escalate to a volcanic eruption on or near Taʻū Island. An eruption could pose significant hazards to residents of American Samoa; these hazards include volcanic gases, volcanic ash, low-level localized explosions of lava, lava flows, earthquake shaking, and tsunami. Volcanic gas and ash travel with the wind, and ocean disturbances may be felt across the Manu’a Islands. Report what you feel and see. Residents can assist USGS and NWS monitoring efforts by noting and reporting accurate times when they feel earthquake shaking or notice other changes that might be related to volcanic activity to either the NOAA Pago Pago National Weather Service Office (https://www.weather.gov/ppg/wsopagooffice) or the American Samoa EOC in Pago Pago (684-699-3800). |
| (15) Contacts: | HVO, askHVO@usgs.gov—best contact for regular reporting and questions. |
| (16) Next Notice: | A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, daily scheduled updates are posted at https://www.usgs.gov/programs/VHP/volcano-updates#hvo. Search for past statements here: https://volcanoes.usgs.gov/hans2/search. |
| (1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA) | |
| (2) Issued: | (20220821/2301Z) |
| (3) Volcano: | Semisopochnoi (VNUM #311060) |
| (4) Current Color Code: | ORANGE |
| (5) Previous Color Code: | YELLOW |
| (6) Source: | Alaska Volcano Observatory |
| (7) Notice Number: | 2022/A927 |
| (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 short-lived explosion occured at 1:47 PM AKDT (21:47 UTC) today that produced ash emissions observed in local webcams. Ash emissions ceased by 2:16 PM AKDT (22:16 UTC). The ash plume was not visible above the meteorological clouds in satellite images, thus was below 20,000 ft. (6 km) above sea level. This event is similar to eruptive activity observed over the last year at Semisopochnoi, but not since June 12. The Aviation Color Code and Volcano Alert Level are being raised to ORANGE/WATCH. Small eruptions producing minor ash deposits within the vicinity of the active north crater of Mount Cerberus and ash clouds usually under 10,000 ft (3 km) above sea level have characterized the recent activity and more ash-producing events could occur again with little warning. |
| (12) Volcanic cloud height: | less than 20,000 ft. above sea level |
| (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, UAFGI, dfee1@alaska.edu, (907) 378-5460 |
| (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 |
| (1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA) | |
| (2) Issued: | (20220820/0001Z) |
| (3) Volcano: | Ofu-Olosega (VNUM #244010) |
| (4) Current Color Code: | YELLOW |
| (5) Previous Color Code: | |
| (6) Source: | Hawaiian Volcano Observatory |
| (7) Notice Number: | 2022/H370 |
| (8) Volcano Location: | S 14 deg 10 min W 169 deg 37 min |
| (9) Area: | American Samoa |
| (10) Summit Elevation: | 2096 ft (639 m) |
| (11) Volcanic Activity Summary: |
An earthquake swarm is occurring in the Manuʻa Islands of American Samoa. As the federal entity responsible for monitoring earthquakes and volcanoes in American Samoa, the U.S. Geological Survey Hawaiian Volcano Observatory (HVO) is assigning the Taʻū Island and Ofu-Olosega Volcano Alert Levels to ADVISORY and Aviation Color Codes YELLOW. The designation previously was UNASSIGNED. This designation does not reflect a change in the behavior of either volcano; it simply acknowledges that the number, size, and frequency of earthquakes being felt by people on Taʻū Island and Ofu-Olosega are well above typical background activity (a NORMAL/GREEN alert level). The first reports of felt earthquakes occurred on July 26, 2022. Personal reports and instruments installed over the past week confirm the continuation of elevated earthquake activity. Data analysis from simple earthquake detection equipment installed on Tutuila, Taʻū, and Ofu-Olosega Islands indicate that the earthquakes are occurring beneath or around the Manuʻa Islands, likely closer to Taʻū rather than Ofu-Olosega. Approximately 20 earthquakes per hour have been recorded for the past several days in the Manuʻa Islands. Estimated magnitudes of the largest earthquakes are between magnitude 2 and 3. The USGS will have more information about the source and cause of the earthquakes next week after expanding the monitoring network. Volcanoes in the Manuʻa Islands are monitored with a limited real-time seismic network consisting of four microseismometers on Tutuila, Taʻū, and Ofu-Olosega Islands. HVO staff are working with the NOAA Pago Pago National Weather Service Office (NWS) to expand the American Samoa monitoring network. Satellite remote sensing is another tool being used, which may detect heat, volcanic gas, and volcanic ash associated with early phases of volcanic activity. Current earthquake monitoring is based on the number and relative size of earthquakes and the estimated distance of earthquakes from the microseismometers. Due to the limitations of the current earthquake monitoring equipment, the exact location, depth, and magnitude of these earthquakes are unknown. Samoan language alert level and color code definitions: https://www.usgs.gov/media/files/volcano-aviation-codes-and-alert-levels-english-and-samoan |
| (12) Volcanic cloud height: | Unknown |
| (13) Other volcanic cloud information: | Unknown |
| (14) Remarks: | Hazards It is unclear if this unrest will escalate to a volcanic eruption. An eruption could pose significant hazards to residents of American Samoa; these hazards include volcanic gases, low-level localized explosions of lava, lava flows, earthquake shaking, and tsunami. Information about these hazards, which are like those in Hawaii, can be found at this HVO website: https://www.usgs.gov/observatories/hvo/hazards. The primary hazard of concern is earthquake shaking, although no damaging earthquakes have occurred as part of this swarm. For information on how to prepare for an earthquake, see https://www.usgs.gov/faqs/what-can-i-do-be-prepared-earthquake. If you feel shaking and are not near the coast, immediately drop, cover, and hold on until the shaking stops. If you are at the coast, heed the natural tsunami warning signs. If you feel a strong or long-duration earthquake, see a sudden rise or fall of the ocean, hear a loud roar from the ocean, or see a large aerial plume from an eruption, a tsunami may follow, and you should immediately move to higher ground. Pacific Tsunami Warning Center: https://tsunami.gov/ Report what you feel and see. Residents can assist USGS and NWS monitoring efforts by noting and reporting accurate times when they feel earthquake shaking or notice other changes that might be related to volcanic activity to either the NOAA Pago Pago National Weather Service Office (https://www.weather.gov/ppg/wsopagooffice) or the American Samoa EOC in Pago Pago (684-699-3800). |
| (15) Contacts: | HVO, askHVO@usgs.gov—best contact for regular reporting and questions. |
| (16) Next Notice: | A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, daily scheduled updates are posted at https://www.usgs.gov/programs/VHP/volcano-updates#hvo. Search for past statements here: https://volcanoes.usgs.gov/hans2/search. |
| (1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA) | |
| (2) Issued: | (20220820/0000Z) |
| (3) Volcano: | Ta'u Island (VNUM #244001) |
| (4) Current Color Code: | YELLOW |
| (5) Previous Color Code: | UNASSIGNED |
| (6) Source: | Hawaiian Volcano Observatory |
| (7) Notice Number: | 2022/H369 |
| (8) Volcano Location: | S 14 deg 13 min W 169 deg 27 min |
| (9) Area: | American Samoa |
| (10) Summit Elevation: | 3054 ft (931 m) |
| (11) Volcanic Activity Summary: |
An earthquake swarm is occurring in the Manuʻa Islands of American Samoa. As the federal entity responsible for monitoring earthquakes and volcanoes in American Samoa, the U.S. Geological Survey Hawaiian Volcano Observatory (HVO) is assigning the Taʻū Island and Ofu-Olosega Volcano Alert Levels to ADVISORY and Aviation Color Codes YELLOW. The designation previously was UNASSIGNED. This designation does not reflect a change in the behavior of either volcano; it simply acknowledges that the number, size, and frequency of earthquakes being felt by people on Taʻū Island and Ofu-Olosega are well above typical background activity (a NORMAL/GREEN alert level). The first reports of felt earthquakes occurred on July 26, 2022. Personal reports and instruments installed over the past week confirm the continuation of elevated earthquake activity. Data analysis from simple earthquake detection equipment installed on Tutuila, Taʻū, and Ofu-Olosega Islands indicate that the earthquakes are occurring beneath or around the Manuʻa Islands, likely closer to Taʻū rather than Ofu-Olosega. Approximately 20 earthquakes per hour have been recorded for the past several days in the Manuʻa Islands. Estimated magnitudes of the largest earthquakes are between magnitude 2 and 3. The USGS will have more information about the source and cause of the earthquakes next week after expanding the monitoring network. Volcanoes in the Manuʻa Islands are monitored with a limited real-time seismic network consisting of four microseismometers on Tutuila, Taʻū, and Ofu-Olosega Islands. HVO staff are working with the NOAA Pago Pago National Weather Service Office (NWS) to expand the American Samoa monitoring network. Satellite remote sensing is another tool being used, which may detect heat, volcanic gas, and volcanic ash associated with early phases of volcanic activity. Current earthquake monitoring is based on the number and relative size of earthquakes and the estimated distance of earthquakes from the microseismometers. Due to the limitations of the current earthquake monitoring equipment, the exact location, depth, and magnitude of these earthquakes are unknown. Samoan language alert level and color code definitions: https://www.usgs.gov/media/files/volcano-aviation-codes-and-alert-levels-english-and-samoan |
| (12) Volcanic cloud height: | Unknown |
| (13) Other volcanic cloud information: | Unknown |
| (14) Remarks: | Hazards It is unclear if this unrest will escalate to a volcanic eruption. An eruption could pose significant hazards to residents of American Samoa; these hazards include volcanic gases, low-level localized explosions of lava, lava flows, earthquake shaking, and tsunami. Information about these hazards, which are like those in Hawaii, can be found at this HVO website: https://www.usgs.gov/observatories/hvo/hazards. The primary hazard of concern is earthquake shaking, although no damaging earthquakes have occurred as part of this swarm. For information on how to prepare for an earthquake, see https://www.usgs.gov/faqs/what-can-i-do-be-prepared-earthquake. If you feel shaking and are not near the coast, immediately drop, cover, and hold on until the shaking stops. If you are at the coast, heed the natural tsunami warning signs. If you feel a strong or long-duration earthquake, see a sudden rise or fall of the ocean, hear a loud roar from the ocean, or see a large aerial plume from an eruption, a tsunami may follow, and you should immediately move to higher ground. Pacific Tsunami Warning Center: https://tsunami.gov/ Report what you feel and see. Residents can assist USGS and NWS monitoring efforts by noting and reporting accurate times when they feel earthquake shaking or notice other changes that might be related to volcanic activity to either the NOAA Pago Pago National Weather Service Office (https://www.weather.gov/ppg/wsopagooffice) or the American Samoa EOC in Pago Pago (684-699-3800). |
| (15) Contacts: | HVO, askHVO@usgs.gov—best contact for regular reporting and questions. |
| (16) Next Notice: | A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, daily scheduled updates are posted at https://www.usgs.gov/programs/VHP/volcano-updates#hvo. Search for past statements here: https://volcanoes.usgs.gov/hans2/search. |
| (1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA) | |
| (2) Issued: | (20220708/1703Z) |
| (3) Volcano: | Semisopochnoi (VNUM #311060) |
| (4) Current Color Code: | YELLOW |
| (5) Previous Color Code: | ORANGE |
| (6) Source: | Alaska Volcano Observatory |
| (7) Notice Number: | 2022/A744 |
| (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 explosive activity have been detected at Semisopochnoi since June 12. Seismic activity continues, but at low levels. Thus the Aviation Color Code and Volcano Alert Level are being lowered to YELLOW/ADVISORY. Steaming and sulfur dioxide emissions from the active north crater of Mount Cerberus continue. Small eruptions producing minor ash deposits within the vicinity of the active north crater of Mount Cerberus and ash clouds usually under 10,000 ft (3 km) above sea level have characterized the recent activity and could begin again with little warning. Semisopochnoi is monitored by local seismic and infrasound sensors, satellite data, web cameras, and remote infrasound and lightning networks. |
| (12) Volcanic cloud height: | none since June 12, 2022 |
| (13) Other volcanic cloud information: | Steam and sulfur dioxide emissions from the active north crater of Mount Cerberus continue |
| (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, 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 |
| (1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA) | |
| (2) Issued: | (20220511/0019Z) |
| (3) Volcano: | Cleveland (VNUM #311240) |
| (4) Current Color Code: | YELLOW |
| (5) Previous Color Code: | UNASSIGNED |
| (6) Source: | Alaska Volcano Observatory |
| (7) Notice Number: | 2022/A502 |
| (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: | Elevated surface temperatures and sulfur dioxide emissions have been detected in satellite data over the past couple of days, representing a departure from background activity. AVO is increasing the Aviation Color Code and Volcano Alert Level from YELLOW/ADVISORY. 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. Eruptions from Cleaveland 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: | 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; Tarsilo Girona, Acting Coordinating Scientist, UAFGI tarsilo.girona@alaska.edu (907) 322-4085 |
| (16) Next Notice: | |
| (1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA) | |
| (2) Issued: | (20220422/0102Z) |
| (3) Volcano: | Davidof (VNUM #311040) |
| (4) Current Color Code: | UNASSIGNED |
| (5) Previous Color Code: | YELLOW |
| (6) Source: | Alaska Volcano Observatory |
| (7) Notice Number: | 2022/A443 |
| (8) Volcano Location: | N 51 deg 57 min E 178 deg 19 min |
| (9) Area: | Aleutians |
| (10) Summit Elevation: | 1076 ft (328 m) |
| (11) Volcanic Activity Summary: | A swarm of earthquakes near Davidof volcano that began in late January 2022 has been in a slow decline over the past few weeks. Thus, the Aviation Color Code and Alert Level are being decreased to UNASSIGNED/UNASSIGNED. AVO only assigns color code and alert level values to volcanoes that are sufficiently instrumented to allow us to understand the background state of activity. The closest seismometers to Davidof are approximately 15 km to the east of the volcano on Little Sitkin Island, and are insufficient to allow us to confirm the volcano is at background. A similar earthquake swarm occurred in December 2021. No signs of unrest associated with either swarm have been observed in satellite images of the volcano. The earthquake activity may be associated with volcanic unrest, or could be due to tectonic activity. |
| (12) Volcanic cloud height: | n/a |
| (13) Other volcanic cloud information: | n/a |
| (14) Remarks: | Davidof volcano is a mostly submerged stratovolcano in the Rat Islands group in the western Aleutian Islands, about 350 km west of Adak. The subaerial part of the volcano comprises Davidof, Khvostof, Pyramid, and Lopy islands, which encircle Crater Bay, a 2.5 km diameter caldera. The islands are built up from interbedded lava flows and explosive deposits. The volcano has been sparsely studied, but visits by Alaska Volcano Observatory geologists in 2021 documented thick sequences of rhyolite to dacite pyroclastic flow and fall deposits that represent the most recent explosive eruptions. The age of these deposits is unknown, but they appear older than Holocene deposits from nearby Segula and Little Sitkin. There are no known historical eruptions from Davidof. |
| (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: | |
| (1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA) | |
| (2) Issued: | (20220422/0059Z) |
| (3) Volcano: | Davidof (VNUM #311040) |
| (4) Current Color Code: | YELLOW |
| (5) Previous Color Code: | YELLOW |
| (6) Source: | Alaska Volcano Observatory |
| (7) Notice Number: | 2022/A434 |
| (8) Volcano Location: | N 51 deg 57 min E 178 deg 19 min |
| (9) Area: | Aleutians |
| (10) Summit Elevation: | 1076 ft (328 m) |
| (11) Volcanic Activity Summary: | A swarm of earthquakes near Davidof volcano that began in late January 2022 has been in a slow decline over the past few weeks. Thus, the Aviation Color Code and Alert Level are being decreased to UNASSIGNED/UNASSIGNED. AVO only assigns color code and alert level values to volcanoes that are sufficiently instrumented to allow us to understand the background state of activity. The closest seismometers to Davidof are approximately 15 km to the east of the volcano on Little Sitkin Island, and are insufficient to allow us to confirm the volcano is at background. A similar earthquake swarm occurred in December 2021. No signs of unrest associated with either swarm have been observed in satellite images of the volcano. The earthquake activity may be associated with volcanic unrest, or could be due to tectonic activity. |
| (12) Volcanic cloud height: | n/a |
| (13) Other volcanic cloud information: | n/a |
| (14) Remarks: | Davidof volcano is a mostly submerged stratovolcano in the Rat Islands group in the western Aleutian Islands, about 350 km west of Adak. The subaerial part of the volcano comprises Davidof, Khvostof, Pyramid, and Lopy islands, which encircle Crater Bay, a 2.5 km diameter caldera. The islands are built up from interbedded lava flows and explosive deposits. The volcano has been sparsely studied, but visits by Alaska Volcano Observatory geologists in 2021 documented thick sequences of rhyolite to dacite pyroclastic flow and fall deposits that represent the most recent explosive eruptions. The age of these deposits is unknown, but they appear older than Holocene deposits from nearby Segula and Little Sitkin. There are no known historical eruptions from Davidof. |
| (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: | |
| (1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA) | |
| (2) Issued: | (20220126/1907Z) |
| (3) Volcano: | Davidof (VNUM #311040) |
| (4) Current Color Code: | YELLOW |
| (5) Previous Color Code: | UNASSIGNED |
| (6) Source: | Alaska Volcano Observatory |
| (7) Notice Number: | 2022/A79 |
| (8) Volcano Location: | N 51 deg 57 min E 178 deg 19 min |
| (9) Area: | Aleutians |
| (10) Summit Elevation: | 1076 ft (328 m) |
| (11) Volcanic Activity Summary: | Over the past two days a swarm of earthquakes has occurred in the vicinity of Davidof volcano. The largest earthquake in the current sequence happened yesterday at 4:02 PM AKST (January 26, 01:02 UTC) and had a magnitude of 4.9. A similar earthquake swarm occurred in December 2021. No signs of unrest have been observed in recent satellite images of the volcano. This earthquake activity may be associated with volcanic unrest, or could be due to regional tectonic activity. Due to the possibility of escalating volcanic unrest, AVO is raising the Aviation Color Code and Volcano Alert Level for Davidof to YELLOW/ADVISORY. AVO continues to monitor the situation with seismometers deployed on nearby islands since there is no real-time seismic monitoring network at Davidof volcano. The closest seismometers to Davidof are approximately 15 km to the east of the volcano on Little Sitkin Island. |
| (12) Volcanic cloud height: | n/a |
| (13) Other volcanic cloud information: | n/a |
| (14) Remarks: | Davidof volcano is a mostly submerged stratovolcano in the Rat Islands group in the western Aleutian Islands, about 350 km west of Adak. The subaerial part of the volcano comprises Davidof, Khvostof, Pyramid, and Lopy islands, which encircle Crater Bay, a 2.5 km diameter caldera. The islands are built up from interbedded lava flows and explosive deposits. The volcano has been sparsely studied, but visits by Alaska Volcano Observatory geologists in 2021 documented thick sequences of rhyolite to dacite pyroclastic flow and fall deposits that represent the most recent explosive eruptions. The age of these deposits is unknown, but they appear older than Holocene deposits from nearby Segula and Little Sitkin. There are no known historical eruptions from Davidof. |
| (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: | |
| (1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA) | |
| (2) Issued: | (20211229/2111Z) |
| (3) Volcano: | Davidof (VNUM #311040) |
| (4) Current Color Code: | UNASSIGNED |
| (5) Previous Color Code: | YELLOW |
| (6) Source: | Alaska Volcano Observatory |
| (7) Notice Number: | 2021/A1184 |
| (8) Volcano Location: | N 51 deg 57 min E 178 deg 19 min |
| (9) Area: | Aleutians |
| (10) Summit Elevation: | 1076 ft (328 m) |
| (11) Volcanic Activity Summary: | The swarm of earthquakes that occurred in the vicinity of Davidof volcano beginning in early December has subsided. Thus, the Aviation Color Code and Alert Level is being decreased to UNASSIGNED/UNASSIGNED. AVO only assigns color code and alert level values to volcanoes that are sufficiently instrumented to allow us to understand the background state of activity. The closest seismometers to Davidof are approximately 15 km to the east of the volcano on Little Sitkin Island, and are insufficient to allow us to assign specific alert levels. Thus, UNASSIGNED is used. |
| (12) Volcanic cloud height: | n/a |
| (13) Other volcanic cloud information: | Unknown |
| (14) Remarks: | Davidof volcano is a mostly submerged stratovolcano in the Rat Islands group in the western Aleutian Islands, about 350 km west of Adak. The subaerial part of the volcano comprises Davidof, Khvostof, Pyramid, and Lopy islands, which encircle Crater Bay, a 2.5 km diameter caldera. The islands are built up from interbedded lava flows and explosive deposits. The volcano has been sparsely studied, but visits by Alaska Volcano Observatory geologists in 2021 documented thick sequences of rhyolite to dacite pyroclastic flow and fall deposits that represent the most recent explosive eruptions. The age of these deposits is unknown, but they appear older than Holocene deposits from nearby Segula and Little Sitkin. There are no known historical eruptions from Davidof. |
| (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: | |
| (1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA) | |
| (2) Issued: | (20211210/2138Z) |
| (3) Volcano: | Davidof (VNUM #311040) |
| (4) Current Color Code: | YELLOW |
| (5) Previous Color Code: | |
| (6) Source: | Alaska Volcano Observatory |
| (7) Notice Number: | 2021/A1108 |
| (8) Volcano Location: | N 51 deg 57 min E 178 deg 19 min |
| (9) Area: | Aleutians |
| (10) Summit Elevation: | 1076 ft (328 m) |
| (11) Volcanic Activity Summary: | Over the past three days a swarm of earthquakes has occurred in the vicinity of Davidof volcano. The largest earthquake to date happened this morning at about 19:45 UTC (10:45 am AKST) and had a magnitude of 4.2. This swarm may be associated with volcanic unrest or it could also be due to regional tectonic activity. Due to the possibility of escalating volcanic unrest, AVO is raising the Aviation Color Code and Volcano Alert Level for Davidof to YELLOW/ADVISORY. AVO is continuing to monitor the situation with seismometers deployed on nearby islands since there is no real-time seismic monitoring network at Davidof volcano. The closest seismometers to Davidof are approximately 15 km to the east of the volcano on Little Sitkin Island. |
| (12) Volcanic cloud height: | no cloud present |
| (13) Other volcanic cloud information: | no cloud present |
| (14) Remarks: | Davidof volcano is a mostly submerged stratovolcano in the Rat Islands group in the western Aleutian Islands, about 350 km west of Adak. The subaerial part of the volcano comprises Davidof, Khvostof, Pyramid, and Lopy islands, which encircle Crater Bay, a 2.5 km diameter caldera. The islands are built up from interbedded lava flows and explosive deposits. The volcano has been sparsely studied, but visits by Alaska Volcano Observatory geologists in 2021 documented thick sequences of rhyolite to dacite pyroclastic flow and fall deposits that represent the most recent explosive eruptions. The age of these deposits is unknown, but they appear older than Holocene deposits from nearby Segula and Little Sitkin. There are no known historical eruptions from Davidof. |
| (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: | |
| (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: | |
| (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: | |
| (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 |
| (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 |
| (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 |
| (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: | |
| (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 |
| (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 |
| (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 |
| (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: | |
| (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: | |
| (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: | |
| (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 |
| (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 |
| (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: | |
| (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: | |
| (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 |
| (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: | |
| (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: | |
| (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: | |
| (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 |
| (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 |
| (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: | |
| (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 |
| (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 |
| (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: | |
| (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: | |
| (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: | |
| (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 |
| (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: | |
| (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: | |
| (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: | |
| (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: | |
| (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 |
| (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 |
| (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 |
| (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: | |
| (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 |
| (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 |
| (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 |
| (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 |
| (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 |
| (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: | |
| (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 |
| (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 |
| (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 |
| (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 |
| (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 |
| (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 |
| (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 |
| (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: | |
| (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: | |
| (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: | |
| (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 |
| (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 |
| (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 |
| (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 |
| (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 |
| (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 |
| (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 |
| (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. |
| (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. |
| (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: | |
| (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 |
| (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: | |
| (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: | |
| (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: | |
| (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: | |
| (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: | |
| (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: | |
| (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: | |
| (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 |
| (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 |
| (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 |
| (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: | |
| (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: | |
| (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: | |
| (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: | |
| (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 |
| (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 |
| (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 |
| (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 |
| (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: | |
| (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: | |
| (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 |
| (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: | |
| (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 |
| (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 |
| (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 |
| (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 |
| (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 |
| (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 |
| (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 |
| (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 |
| (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 |
| (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: | |
| (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 |
| (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 |
| (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: | |
| (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: | |
| (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: | |
| (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: | |
| (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 |
| (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 |
| (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 |
| (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 |
| (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: | |
| (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 |
| (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 |
| (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 |
| (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 |
| (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: | |
| (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 |
| (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 |
| (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 |
| (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: | |
| (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: | |
| (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: | |
| (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 |
| (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. |
| (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: | |
| (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: | |
| (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: | |
| (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: | |
| (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: | |
| (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 |
| (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: | |
| (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 |
| (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: | |
| (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 |
| (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 |
| (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 |
| (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 |
| (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 |
| (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. |
| (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 |
| (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 |
| (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 |
| (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 |
| (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: | |
| (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: | |
| (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: | |
| (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: | |
| (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. |
| (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 |
| (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: | |
| (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/ |
| (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/ |
| (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: | |
| (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: | |
| (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: | |
| (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: | |
| (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: | |
| (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: | |
| (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: | |
| (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: | |
| (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: | |
| (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: | |
| (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: | |
| (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 |
| (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: | |
| (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: | |
| (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: | |
| (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: | |
| (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: | |
| (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 |
| (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: | |
| (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: | |
| (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: | |
| (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: | |
| (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: | |
| (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: | |
| (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: | |
| (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: | |
| (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: | |
| (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: | |
| (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: | |
| (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: | |
| (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: | |
| (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: | |
| (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: | |
| (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: | |
| (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: | |
| (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: | |
| (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: | |
| (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: | |
| (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 Activit | |