Skip to main content
U.S. flag

An official website of the United States government

Volcano Updates

Volcano observatories issue updates and other types of notifications as activity warrants.

Gareloi Advisory Level = ADVISORY Aviation Color Code = YELLOW. As of 2024-02-25 20:24:37 UTC, AVO Gareloi YELLOW/ADVISORY - Low-level seismicity continues. Change to current status on 2024-02-12 22:10:54 UTC from Alert Level NORMAL and Aviation Color Code GREEN
For more information, see: https://volcanoes.usgs.gov/hans2/view/notice/DOI-USGS-AVO-2024-02-25T20:17:53+00:00
Kanaga Advisory Level = ADVISORY Aviation Color Code = YELLOW. As of 2024-02-25 20:24:37 UTC, AVO Kanaga YELLOW/ADVISORY - No significant activity. Change to current status on 2023-12-19 21:01:59 UTC from Alert Level NORMAL and Aviation Color Code GREEN
For more information, see: https://volcanoes.usgs.gov/hans2/view/notice/DOI-USGS-AVO-2024-02-25T20:17:53+00:00
Great Sitkin Advisory Level = WATCH Aviation Color Code = ORANGE. As of 2024-02-25 20:24:37 UTC, AVO Great Sitkin ORANGE/WATCH - Slow eruption of lava likely continues. Change to current status on 2021-07-23 22:25:55 UTC from Alert Level ADVISORY and Aviation Color Code YELLOW
For more information, see: https://volcanoes.usgs.gov/hans2/view/notice/DOI-USGS-AVO-2024-02-25T20:17:53+00:00
Shishaldin Advisory Level = ADVISORY Aviation Color Code = YELLOW. As of 2024-02-25 20:24:37 UTC, AVO Shishaldin YELLOW/ADVISORY - Low-level earthquake activity continues. Change to current status on 2024-02-17 20:26:00 UTC from Alert Level WATCH and Aviation Color Code ORANGE
For more information, see: https://volcanoes.usgs.gov/hans2/view/notice/DOI-USGS-AVO-2024-02-25T20:17:53+00:00
Kilauea Advisory Level = ADVISORY Aviation Color Code = YELLOW. As of 2024-02-25 18:39:57 UTC, HVO Kilauea YELLOW/ADVISORY - Kīlauea volcano is not erupting. Low to moderate levels of unrest continue in the south caldera and to the southwest.  Change to current status on 2024-02-03 18:10:55 UTC from Alert Level WATCH and Aviation Color Code ORANGE
For more information, see: https://volcanoes.usgs.gov/hans2/view/notice/DOI-USGS-HVO-2024-02-25T18:35:56+00:00
Ahyi Seamount Advisory Level = ADVISORY Aviation Color Code = YELLOW. As of 2024-02-22 22:12:19 UTC, NMI Ahyi Seamount YELLOW/ADVISORY - Plumes of discolored water observed by satellite. Change to current status on 2024-01-13 22:50:58 UTC from Alert Level UNASSIGNED and Aviation Color Code UNASSIGNED
For more information, see: https://volcanoes.usgs.gov/hans2/view/notice/DOI-USGS-NMI-2024-02-22T20:55:55+00:00

ALASKA VOLCANO OBSERVATORY DAILY UPDATE
U.S. Geological Survey
Sunday, February 25, 2024, 11:24 AM AKST (Sunday, February 25, 2024, 20:24 UTC)


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

Slow eruption of lava in the summit crater of Great Sitkin Volcano likely continues. Seismicity was low over the past day with a few earthquakes observed. No activity was observed in cloudy satellite and webcam images.

The current lava flow began erupting in July 2021. No explosive events have occurred since a single event in May 2021.

Local seismic and infrasound sensors and web cameras are used to monitor Great Sitkin along with regional infrasound and lightning networks and satellite data.



GARELOI (VNUM #311070)
51°47'21" N 178°47'46" W, Summit Elevation 5161 ft (1573 m)
Current Volcano Alert Level: ADVISORY
Current Aviation Color Code: YELLOW

Seismicity has declined over the past several days but remains slightly elevated with small low frequency earthquakes observed. These earthquakes are not uncommon at Gareloi. No activity was observed in cloudy satellite and webcam images over the past day.

Mount Gareloi persistently emits magmatic gases from a fumarole field on the south crater and commonly exhibits low-level seismic activity. 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 magmatic system.

Mount Gareloi is monitored by a local seismic and infrasound network, satellite data, and regional infrasound and lightning-detection networks.



SHISHALDIN (VNUM #311360)
54°45'19" N 163°58'16" W, Summit Elevation 9373 ft (2857 m)
Current Volcano Alert Level: ADVISORY
Current Aviation Color Code: YELLOW

Low-level unrest continues at Shishaldin Volcano with occasional small volcanic earthquakes. No activity was observed in cloudy satellite and webcam images from the past day.

No significant eruptive activity has been observed since November 2023. 

Local seismic and infrasound sensors, web cameras, and a geodetic network are used to monitor Shishaldin Volcano. In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions. 



KANAGA (VNUM #311110)
51°55'27" N 177°9'44" W, Summit Elevation 4288 ft (1307 m)
Current Volcano Alert Level: ADVISORY
Current Aviation Color Code: YELLOW

Seismicity was quiet at Kanaga Volcano over the past day. No activity was observed in cloudy satellite and webcam images. 

A steam-driven explosion occurred at Kanaga on December 18, 2023 and since then, seismic activity at the volcano has been above background. This unrest may mean that the likelihood of explosive ash-producing activity has increased.

Local seismic and infrasound sensors and web cameras are used to monitor Kanaga. AVO also uses regional infrasound and lightning networks as well as satellite data.





CONTACT INFORMATION:

Matt Loewen, Acting Scientist-in-Charge, USGS mloewen@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI dfee1@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, February 20, 2024, 2:31 PM PST (Tuesday, February 20, 2024, 22:31 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 February 12, 2024 (0000h PST) to February 18, 2024 (2359h PST)

One earthquake greater than M1 was recorded within the Clear Lake Volcanic Field, with a magnitude of M1.1. Typical seismicity was recorded at The Geysers geothermal field south of the Clear Lake Volcanic Field; 123 earthquakes greater than M1 were recorded, with the largest having a magnitude of M2.5.

Three earthquakes greater than M1 were recorded in the Long Valley Caldera, with the largest having a magnitude of M1.4. One earthquake having a magnitude greater than M1 was recorded at Mammoth Mountain, having a magnitude of M1.0. Five earthquakes greater than M1 were recorded in the Sierra Nevada Block, south of Mammoth Mountain and Long Valley, with the largest having a magnitude of M2.0.

Three earthquakes greater than M1 were recorded in the Coso Volcanic Field, with the largest having a magnitude of M1.3.

Four earthquakes greater than M1 were recorded near the Salton Buttes, with the largest having a magnitude of M1.9.



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, February 23, 2024, 12:45 PM PST (Friday, February 23, 2024, 20:45 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 activity levels. 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.

Past Week Observations: Earthquakes consistent with background level activity were detected by monitoring stations at Mount Rainier, Mount St. Helens, and Mount Hood during the past week.



The U.S. Geological Survey Cascades Volcano Observatory and the University of Washington Pacific Northwest Seismic Network continue to monitor Washington and Oregon volcanoes closely and will issue additional notifications 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


HAWAIIAN VOLCANO OBSERVATORY DAILY UPDATE
U.S. Geological Survey
Sunday, February 25, 2024, 8:39 AM HST (Sunday, February 25, 2024, 18:39 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. Low to moderate rates of seismicity at the summit and along the Koaʻe fault system southwest of the summit continues following an intrusion of magma into the area at the end of January. 

Summit Observations:  Seismicity beneath the summit and extending 5-7 miles (8-11 km) southwest of the caldera under the Koaʻe fault zone continues. Earthquakes are dispersed widely from the summit to the southwest. There were 2 earthquakes recorded near the summit over the past 24 hours. Depths beneath the summit are 0.5-6 miles (1–10 km) below the surface, and magnitudes are typically below M2.0. 

Ground deformation remains low with tiltmeters near Sand Hill showing modest changes in the past day. 

Sulfur dioxide (SO2) gas emission rates have remained low since October 2023. An SO2 emission rate of approximately 100 tonnes per day was recorded on February 16. 

An Information Statement about the recent intrusion can be found here: USGS Volcano Notice - DOI-USGS-HVO-2024-02-09T05:11:03+00:00.
The overall decrease in seismicity and deformation suggests that this event is waning. However, renewed episodes of activity remain a possibility and an eruption could occur with little advanced warning. 

Rift Zone Observations: Seismicity in Kīlauea's upper East Rift Zone and Southwest Rift Zone remain low. No unusual activity has been noted along the middle and lower sections of Kīlauea's East Rift Zone. We continue to closely monitor both rift zones. 

Measurements from continuous gas monitoring stations downwind of Puʻuʻōʻō in the middle East Rift Zone—the site of 1983–2018 eruptive activity—continue to be below detection limits for SO2, indicating that SO2 emissions Puʻuʻōʻō are negligible.    

Hazard Analysis:  Levels of volcanic gases (sulfur dioxide and carbon dioxide) can remain locally hazardous even when Kīlauea is not erupting. Local concentrations of sulfur dioxide (SO2) and/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. For discussion of Kīlauea hazards, please see: https://www.usgs.gov/observatories/hawaiian-volcano-observatory/hazards.    

 

 



More Information:



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:

askHVO@usgs.gov



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 WEEKLY UPDATE
U.S. Geological Survey
Friday, February 23, 2024, 8:12 AM ChST (Thursday, February 22, 2024, 22:12 UTC)


Report prepared by the U.S. Geological Survey.



AHYI SEAMOUNT (VNUM #284141)
20°25'12" N 145°1'48" E, Summit Elevation -259 ft (-79 m)
Current Volcano Alert Level: ADVISORY
Current Aviation Color Code: YELLOW

Discolored water plumes near Ahyi Seamount were observed in satellite images on February 18 and February 19. There were two signals observed on underwater pressure sensors near Wake Island (1,410 miles east of Ahyi) that may be related to activity at Ahyi. 

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 underwater pressure sensors, seismic, and satellite data closely.



Ahyi seamount is a large conical submarine volcano that rises to within 260 feet (79 m) of the sea surface about 11 miles (18 km) southeast of the island of Farallon de Pajaros (Uracas) in the Northern Mariana Islands. Water discoloration has been observed over the submarine volcano during previous periods of activity, and in 1979 the crew of a fishing boat felt shocks over the summit area followed by upwelling of sulfur-bearing water. From April 24 to 25, 2001, an explosive submarine eruption was detected seismically from a seismic station on Rangiroa Atoll, Tuamotu Archipelago. The event was well constrained (+/- 9 miles or 15 km) at a location near the southern base of Ahyi; the summit of the seamount lies within the location uncertainty. Another eruption was detected from April 24 to May 17, 2014, using data from seismometers located on subaerial volcanoes in the Northern Mariana Islands and hydrophone arrays at Wake Island. NOAA divers also reported hearing explosions while conducting coral reef research on nearby Farallon de Pajaros. The 2014 eruption of Ahyi formed a new crater near the summit of the volcano and a large landslide chute developed on its southeast flank. More recently, an eruption from October 2022 to May 2023 occurred, characterized by submarine plumes and geophysical detections of activity on the hydrophone arrays at Wake Island.



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
Thursday, February 1, 2024, 12:15 PM MST (Thursday, February 1, 2024, 19:15 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 eruptions of Steamboat Geyser in January, although minor activity began at the geyser on about January 20 and continued through the end of the month.  This suggests that the geyser will erupt soon, possibly in the first half of February.

 

Seismicity

During January 2024, the University of Utah Seismograph Stations, responsible for the operation and analysis of the Yellowstone Seismic Network, located 226 earthquakes in the Yellowstone National Park region. The largest event of the month was a minor earthquake of magnitude 3.3 located about 10 miles north-northeast of Old Faithful in Yellowstone National Park on January 3 at 5:10 PM MST.  

December seismicity in Yellowstone was marked by two swarms:

1. A swarm of 119 earthquakes, located approximately 10 miles north-northeast of Old Faithful, occurred January 1–10. The largest earthquake in the sequence was also the largest of the month (described above).

2. A swarm of 38 earthquakes occurred approximately 9 miles east-northeast of West Yellowstone, MT, during January 6–7. The largest earthquake in the sequence was a magnitude 2.1 event on January 5 at 4:24 PM 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

During the month of January, continuous GPS stations in Yellowstone caldera showed subsidence, which has been ongoing since 2015, interrupted in summer months by a pause or slight uplift caused by seasonal changes related to snowmelt and groundwater conditions.  The caldera has subsided by slightly more than 2 cm (about 1 in) since the end of September.  No significant deformation has occurred at Norris Geyser Basin since the end of summer.

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, Earthscope Consortium, 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)
2024-02-17 - Shishaldin, Aviation Color Code: YELLOW (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20240217/2026Z)
(3) Volcano: Shishaldin (VNUM #311360)
(4) Current Color Code: YELLOW
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2024/A176
(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:

Shishaldin Volcano is not showing any signs of ongoing ash emissions or eruptive activity. Seismicity remains elevated with ongoing volcanic earthquakes, but there is no indication of explosive activity or the presence of lava in the crater. The current activity is consistent with continued volcanic unrest but not an active eruption, and AVO is lowering the Aviation Color Code to YELLOW and Volcano Alert Level to ADVISORY.

The last significant eruptive activity was in November 2023.

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network. In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to monitor the volcano.

(12) Volcanic cloud height: Unknown
(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 10 miles (16 km). A 660 ft. (200 m) wide 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 26 confirmed eruptions since 1824. Most eruptions are relatively small, although the April-May 1999 event generated an ash column that reached 45,000 ft. (14 km) above sea level.

(15) Contacts:

Matt Haney, Scientist-in-Charge, USGS mhaney@usgs.gov (907) 786-7497

Pavel Izbekov, Acting Coordinating Scientist, UAFGI peizbekov@alaska.edu (907) 378-5460

(16) Next Notice:
2024-02-12 - Gareloi, Aviation Color Code: YELLOW (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20240212/2210Z)
(3) Volcano: Gareloi (VNUM #311070)
(4) Current Color Code: YELLOW
(5) Previous Color Code: GREEN
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2024/A158
(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:

Over the past several hours, AVO has detected an increase in seismicity at Mount Gareloi (Gareloi volcano) beginning at 09:15 AKST (18:15 UTC). The current activity marks a change in character above background rates, and AVO is raising the Aviation Color Code to YELLOW and Volcano Alert Level to ADVISORY.

There have been no other notable changes at the volcano in satellite data or webcam views. Mount Gareloi 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.

Mount 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, Scientist-in-Charge, USGS mhaney@usgs.gov (907) 786-7497

Ronni Grapenthin, Acting Coordinating Scientist, UAFGI, rgrapenthin@alaska.edu (907) 378-5460

(16) Next Notice:
2024-02-11 - Shishaldin, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20240211/2146Z)
(3) Volcano: Shishaldin (VNUM #311360)
(4) Current Color Code: ORANGE
(5) Previous Color Code: YELLOW
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2024/A152
(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:

Volcanic activity at Shishaldin Volcano has increased slightly, and minor ash emissions were observed in a web camera image from 18:25 UTC (9:25 AM) this morning. The ash in the web camera image extends from the summit crater and drapes down over the volcano's north flank. This ash emission episode corresponds with seismic signals typically associated with surficial mass flows. The low-level ash cloud may result from a non-eruptive collapse of previously emplaced ash and pyroclastic debris on the upper part of the Shishaldin cone.

Clouds have obscured summit views in web camera images after the 18:25 UTC image. No ash clouds have been observed in satellite imagery. Thus, the Aviation Color Code and the Volcano Alert Level are being raised to ORANGE/WATCH.

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network. In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

(12) Volcanic cloud height: At summit (9375 ft)
(13) Other volcanic cloud information: Evident in ony 1 web cam image from 18:25 UTC
(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 10 miles (16 km). A 660 ft. (200 m) wide 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 26 confirmed eruptions since 1824. Most eruptions are relatively small, although the April-May 1999 event generated an ash column that reached 45,000 ft. (14 km) above sea level.

(15) Contacts:

Matt Haney, Scientist-in-Charge, USGS mhaney@usgs.gov (907) 786-7497

Ronni Grapenthin, Acting Coordinating Scientist, UAFGI, rgrapenthin@alaska.edu (907) 378-5460

(16) Next Notice:
2024-02-03 - Kilauea, Aviation Color Code: YELLOW (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20240203/1810Z)
(3) Volcano: Kilauea (VNUM #332010)
(4) Current Color Code: YELLOW
(5) Previous Color Code: ORANGE
(6) Source: Hawaiian Volcano Observatory
(7) Notice Number: 2024/H53
(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:

Earthquake and ground deformation rates extending from Kīlauea summit southwest along the Koa‘e fault system have decreased significantly over the past 24 hours. The intrusion of magma into this area appears to have slowed, and the likelihood of an eruption has decreased.  

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.   

In total, more than 3,000 earthquakes were recorded over the past week during this event, which coincided with ground deformation patterns indicative of magma moving from beneath the summit to the southwest under the Koa‘e fault system. More information on this intrusive activity will be available in the Kīlauea daily update published later today. Additional details on this event can be found in previously published official notices:  

 

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

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 volcano alert levels and 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: 

Kīlauea summit eruptive activity over the past several years has occurred at the base of Halemaʻumaʻu crater and on the downdropped block, within the closed area of Hawaiʻi Volcanoes National Park. During Kīlauea summit eruptions, the high level of volcanic gas—primarily water vapor (H2O), carbon dioxide (CO2), and sulfur dioxide (SO2)—being emitted is the primary hazard of concern, as this hazard can have far-reaching effects downwind. Passive volcanic degassing can occur from within Halemaʻumaʻu crater even during periods of no eruptive activity. As SO2 is released from the summit, it reacts in the atmosphere to create the visible haze known as vog (volcanic smog) that has been observed downwind of Kīlauea. Vog creates the potential for airborne health hazards to residents and visitors, damages agricultural crops and other plants, and affects livestock. For more information on gas hazards at the summit of Kīlauea, please see: https://pubs.er.usgs.gov/publication/fs20173017. Vog information can be found at https://vog.ivhhn.org.  

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

Please see the Hawaiʻi Volcanoes National Park website for visitor information: https://www.nps.gov/havo/index.htm. 

(15) Contacts:

askHVO@usgs.gov

(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:

2024-01-31 - Kilauea, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20240131/1441Z)
(3) Volcano: Kilauea (VNUM #332010)
(4) Current Color Code: ORANGE
(5) Previous Color Code: YELLOW
(6) Source: Hawaiian Volcano Observatory
(7) Notice Number: 2023/H333
(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 inflationary ground deformation at Kīlauea’s summit began occurring during the early morning hours of January 31, 2024, indicating movement of magma in the subsurface.   

The USGS Hawaiian Volcano Observatory is raising the volcano alert level/aviation color code for Kīlauea from ADVISORY/YELLOW to WATCH/ORANGE due to this activity.

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. Patterns of earthquake activity and ground deformation are concentrated south of the caldera region. Any new eruptive activity could occur in or near Halemaʻumaʻu crater or the region south of Kīlauea caldera, within the closed area of Hawaiʻi Volcanoes National Park. 

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

HVO continues to closely monitor this activity. Should activity change significantly, a new Volcanic Activity Notice will be issued. 

Hazards are 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 volcano alert levels and 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: 

Kīlauea summit eruptive activity over the past several years has occurred at the base of Halemaʻumaʻu crater and on the downdropped block, within the closed area of Hawaiʻi Volcanoes National Park. During Kīlauea summit eruptions, the high level of volcanic gas—primarily water vapor (H2O), carbon dioxide (CO2), and sulfur dioxide (SO2)—being emitted is the primary hazard of concern, as this hazard can have far-reaching effects downwind. Passive volcanic degassing can occur from within Halemaʻumaʻu crater even during periods of no eruptive activity. As SO2 is released from the summit, it reacts in the atmosphere to create the visible haze known as vog (volcanic smog) that has been observed downwind of Kīlauea. Vog creates the potential for airborne health hazards to residents and visitors, damages agricultural crops and other plants, and affects livestock. For more information on gas hazards at the summit of Kīlauea, please see: https://pubs.er.usgs.gov/publication/fs20173017. Vog information can be found at https://vog.ivhhn.org.  

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

Please see the Hawaiʻi Volcanoes National Park website for visitor information: https://www.nps.gov/havo/index.htm. 

(15) Contacts:

askHVO@usgs.gov

(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:

2024-01-13 - Ahyi Seamount, Aviation Color Code: YELLOW (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20240113/2250Z)
(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: 2024/N5
(8) Volcano Location: N 20 deg 25 min E 145 deg 1 min
(9) Area: Northern Mariana Islands
(10) Summit Elevation: -259 ft (-79 m)
(11) Volcanic Activity Summary:

Signs of unrest at Ahyi Seamount have been observed in satellite data over the past few weeks. Plumes of discolored water were observed drifting 1.5–6.2 miles (2.4–10 km) away from the volcano in satellite images on December 24 and 31, 2023 and January 4 and 10, 2024. Nothing significant has been detected from the direction of Ahyi in hydroacoustic array data at Wake Island; however, submarine plumes have been observed at Ahyi in the past without clear hydroacoustic signals. Due to the increased likelihood of an underwater eruption occurring at Ahyi Seamount, the Aviation Color Code and Volcano Alert Level are being raised to YELLOW and ADVISORY. We will continue to monitor satellite and distal hydroacoustic data for additional evidence of volcanic activity.

An undersea eruption at Ahyi Seamount was last detected starting mid-October 2022. The activity appeared to pause beginning in early April 2023 but briefly resumed in late May 2023.

 

 

(12) Volcanic cloud height: No volcanic cloud produced
(13) Other volcanic cloud information: Unknown
(14) Remarks:

Ahyi seamount is a large conical submarine volcano that rises to within 450 ft (137 m) of the sea surface about 11 miles (18 km) southeast of Farallon de Pajaros (Uracas) Island in the northern Marianas, about 370 miles (600 km) 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 (+/- 9 miles or 15 km) at a location near the southern base of Ahyi.
 

(15) Contacts:

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

(16) Next Notice:

A new VAN will be issued if conditions change significantly or alert levels are modified.

2024-01-10 - Trident, Aviation Color Code: GREEN (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20240110/2004Z)
(3) Volcano: Trident (VNUM #312160)
(4) Current Color Code: GREEN
(5) Previous Color Code: YELLOW
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2024/A38
(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:

Volcanic activity beneath Trident Volcano has decreased over the past month.  Occasional small earthquakes continue to be observed; however, the current activity is at background levels.  No evidence of ground deformation has been observed since the end of November 2023.  Due to this decrease in activity, the Alaska Volcano Observatory is lowering the Aviation Color Code and Volcano Alert Level to GREEN/NORMAL.

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:

Aaron Wech, Acting Scientist-in-Charge, USGS awech@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.

2024-01-02 - Shishaldin, Aviation Color Code: YELLOW (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20240102/2033Z)
(3) Volcano: Shishaldin (VNUM #311360)
(4) Current Color Code: YELLOW
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2024/A5
(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:

Volcanic activity at Shishaldin Volcano has gradually declined over the past two months since the last significant explosive event on November 3, 2023. Small explosions within the summit crater continue to be detected in infrasound data during periods of quiet (low wind) conditions but new deposits have not recently been seen inside or outside the crater. Satellite-observed surface temperatures remain low, suggesting lava is not present in the crater. The current activity is consistent with continued volcanic unrest but not an active eruption. Thus, the Aviation Color Code and the Volcano Alert Level are being decreased to YELLOW/ADVISORY.

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network. In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

(12) Volcanic cloud height: none observed
(13) Other volcanic cloud information: intermittent steaming continues
(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 10 miles (16 km). A 660 ft. (200 m) wide 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 26 confirmed eruptions since 1824. Most eruptions are relatively small, although the April-May 1999 event generated an ash column that reached 45,000 ft. (14 km) above sea level.

(15) Contacts:

Dave Schneider, Acting Scientist-in-Charge, USGS djschneider@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI dfee1@alaska.edu (907) 378-5460

(16) Next Notice:
2024-01-01 - Ahyi Seamount, Aviation Color Code: UNASSIGNED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20240101/2222Z)
(3) Volcano: Ahyi Seamount (VNUM #284141)
(4) Current Color Code: UNASSIGNED
(5) Previous Color Code: UNASSIGNED
(6) Source: U.S. Geological Survey
(7) Notice Number: 2024/N1
(8) Volcano Location: N 20 deg 25 min E 145 deg 1 min
(9) Area: Northern Mariana Islands
(10) Summit Elevation: -259 ft (-79 m)
(11) Volcanic Activity Summary:

A plume of discolored water was observed in the vicinity of Ahyi Seamount in satellite images from yesterday afternoon (January 1, 2024 local time). It is possible that this plume is due to underwater volcanic activity however pressure sensors at Wake Island that have been used in the past to confirm underwater volcanic activity are not currently operational. More distant sensors have not registered any activity.  It is therefore not possible to confirm volcanic activity at Ahyi Seamount in independent data streams and the Aviation Color Code and Volcano Alert Level remain at UNASSIGNED. We will continue to monitor satellite data for additional evidence of discolored water associated with underwater volcanic activity.

Starting mid-October 2022, hydroacoustic sensors at Wake Island, 1,410 miles (2,270 km) east of Ahyi, began recording signals consistent with activity from an undersea volcanic source. In collaboration with the Laboratoire de Geophysique in Tahiti, a combined analysis of the hydroacoustic signals and data from seismic stations located at Guam and Chichijima Island, Japan, confirmed that the source of this activity was at or near Ahyi seamount. Observations of discolored water above the seamount in satellite data confirmed activity at Ahyi. The activity appears to have paused beginning in early April 2023 but briefly resumed in late May 2023.  

 

 

(12) Volcanic cloud height: No volcanic cloud produced
(13) Other volcanic cloud information: Unknown
(14) Remarks:

Ahyi seamount is a large conical submarine volcano that rises to within 450 ft (137 m) of the sea surface about 11 miles (18 km) southeast of Farallon de Pajaros (Uracas) Island in the northern Marianas, about 370 miles (600 km) 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 (+/- 9 miles or 15 km) at a location near the southern base of Ahyi.
 

(15) Contacts:

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

(16) Next Notice:

A new VAN will be issued if conditions change significantly or alert levels are modified.

2023-12-19 - Kanaga, Aviation Color Code: YELLOW (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20231219/2101Z)
(3) Volcano: Kanaga (VNUM #311110)
(4) Current Color Code: YELLOW
(5) Previous Color Code: GREEN
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2023/A1742
(8) Volcano Location: N 51 deg 55 min W 177 deg 9 min
(9) Area: Aleutians
(10) Summit Elevation: 4288 ft (1307 m)
(11) Volcanic Activity Summary:

A small explosion was detected at Kanaga Volcano overnight at 22:31 AKST Dec 18 (07:31 UTC Dec. 19), and AVO is increasing the Aviation Color Code to YELLOW and the Volcano Alert Level to ADVISORY.  The event was detected in local infrasound and seismic data and was followed by elevated earthquake seismicity that is ongoing.  No ash emisions have been observed in partly cloudy satellite images.

(12) Volcanic cloud height: Unknown
(13) Other volcanic cloud information: Unknown
(14) Remarks:
(15) Contacts:

Matt Haney, Scientist-in-Charge, USGS mhaney@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

2023-11-24 - Bogoslof, Aviation Color Code: UNASSIGNED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20231124/1912Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: UNASSIGNED
(5) Previous Color Code: YELLOW
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2023/A1661
(8) Volcano Location: N 53 deg 55 min W 168 deg 2 min
(9) Area: Aleutians
(10) Summit Elevation: 492 ft (150 m)
(11) Volcanic Activity Summary:

Following the seismic swarm that began at Bogoslof around October 22, 2023 the frequency of earthquakes has now subsided to background levels. During the swarm 5 to 10 events per hour and up to a total of ~1,100 earthquakes were recorded in one week. The decline in seismicity has been observed over the past 3 weeks, with the last moderate earthquake (M2.7) recorded on November 9. No other signs of volcanic unrest have been detected. In response, AVO is lowering the Aviation Color Code and Volcano Alert Level to UNASSIGNED. 

Bogoslof volcano is monitored using a single local seismic station, distant seismic and infrasound instruments, satellite data, and lightning networks.

(12) Volcanic cloud height: None
(13) Other volcanic cloud information: N/A
(14) Remarks:

At least nine historical eruptions have been documented at Bogoslof volcano. The most recent occurred from December 2016 to August 2017 and produced seventy main explosive events that generated volcanic ash clouds that rose as high as 42,500 ft (13 km) above sea level, and greatly modified the topography of Bogoslof Island.  Previous eruptions of the volcano have lasted weeks to months and have on occasion produced ash fall on the community of Unalaska. Eruptions of the volcano are often characterized by multiple explosive ash-producing events as well as the growth of lava domes.

Bogoslof Island is the largest of a cluster of small, low-lying islands making up the summit of a large submarine stratovolcano. The highest point above sea level is about 490 ft (150 m); however, the volcano is frequently altered by both eruptions and wave erosion and has undergone dramatic changes in historical time. The two main islands currently above sea level are Fire Island and Bogoslof Island, both located about 61 miles (98 km) northwest of Unalaska/Dutch Harbor, 76 miles (123 km) northeast of Nikolski, and 93 miles (149 km) northeast of Akutan. The volcano is situated slightly north (behind) the main Aleutian volcanic front. Bogoslof volcano is within the U.S. Fish and Wildlife Service Alaska Maritime National Wildlife Refuge and is habitat for marine mammals and seabirds (https://www.fws.gov/refuge/alaska_maritime/).

(15) Contacts:

Matt Loewen, Acting Scientist-in-Charge, USGS mloewen@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI dfee1@alaska.edu (907) 378-5460

(16) Next Notice:
2023-11-03 - Shishaldin, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20231103/1631Z)
(3) Volcano: Shishaldin (VNUM #311360)
(4) Current Color Code: ORANGE
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2023/A1578
(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:

Low-level ash emissions at Shishaldin Volcano are no longer visible in satellite data and seismicity and infrasound data show a decline in activity.  The Aviation Color Code and Alert Level remain at ORANGE/WATCH. AVO is monitoring the volcano closely and will issue additional Volcanic Activity Notices about significant changes in activity as they occur.

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network. In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

(12) Volcanic cloud height: none observed
(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 10 miles (16 km). A 660 ft. (200 m) wide 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 26 confirmed eruptions since 1824. Most eruptions are relatively small, although the April-May 1999 event generated an ash column that reached 45,000 ft. (14 km) above sea level.

(15) Contacts:

Matt Haney, Scientist-in-Charge, USGS mhaney@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI dfee1@alaska.edu (907) 378-5460

(16) Next Notice:
2023-11-03 - Shishaldin, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20231103/0545Z)
(3) Volcano: Shishaldin (VNUM #311360)
(4) Current Color Code: ORANGE
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2023/A1577
(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:

An explosive eruption of Shishaldin Volcano began around 03:40 UTC on November 3 (19:40 AKDT on November 2). Ash was first observed in satellite data at 04:00 UTC (20:00 AKDT) at an altitude of 20,000 ft above sea level. This is a decrease in the cloud height from the initial estimate and the National Weather Service has modified their SIGMET because of the refined analysis of the cloud altitude. Seismic, infrasound and satellite data show the eruption continues at a constant level. The Aviation Color Code and Alert Level remain at ORANGE/WATCH. AVO is monitoring the volcano closely and will issue additional Volcanic Activity Notices about significant changes in activity as they occur.

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network. In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

(12) Volcanic cloud height: 20,000 ft
(13) Other volcanic cloud information: moving towards the west
(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 10 miles (16 km). A 660 ft. (200 m) wide 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 26 confirmed eruptions since 1824. Most eruptions are relatively small, although the April-May 1999 event generated an ash column that reached 45,000 ft. (14 km) above sea level.

(15) Contacts:

Matt Haney, Scientist-in-Charge, USGS mhaney@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI dfee1@alaska.edu (907) 378-5460

(16) Next Notice:
2023-11-03 - Shishaldin, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20231103/0431Z)
(3) Volcano: Shishaldin (VNUM #311360)
(4) Current Color Code: ORANGE
(5) Previous Color Code: YELLOW
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2023/A1575
(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 level of unrest has increased at Shishaldin Volcano. An increase in tremor has been observed in seismic and infrasound data beginning at around 7:00 pm AKDT (3:00 UTC 11/3). These signals indicate that the volcano is likely erupting. No ash cloud has been observed in satellite data.  Due to the increase in activity, the Aviation Color Code and Volcano Alert Level for Shishaldin Volcano are being raised to ORANGE/WATCH.  

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network. In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

(12) Volcanic cloud height: NA
(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 10 miles (16 km). A 660 ft. (200 m) wide 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 26 confirmed eruptions since 1824. Most eruptions are relatively small, although the April-May 1999 event generated an ash column that reached 45,000 ft. (14 km) above sea level.

(15) Contacts:

Matt Haney, Scientist-in-Charge, USGS mhaney@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI dfee1@alaska.edu (907) 378-5460

(16) Next Notice:
2023-10-31 - Shishaldin, Aviation Color Code: YELLOW (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20231031/2051Z)
(3) Volcano: Shishaldin (VNUM #311360)
(4) Current Color Code: YELLOW
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2023/A1562
(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:

Volcanic activity at Shishaldin Volcano has decreased over the past few weeks. While current seismicity consisting of low-level tremor and small low frequency earthquakes continues above background levels, there have been no large ash-producing explosions at the volcano since October 3, 2023. Recent satellite observations also show a decrease in surface temperatures and a decline in sulfur dioxide emissions. Due to this decrease in activity, the Alaska Volcano Observatory is lowering the Aviation Color Code for Shishaldin Volcano to YELLOW and the Alert Level to ADVISORY.

The recent episode of activity at Shishaldin began on July 11, 2023 with the observation of strongly elevated surface temperatures at the summit in satellite data and increasing seismic activity. A significant explosion was observed on July 14 2023 that produced an ash cloud to over 30,000 ft. Eleven more significant explosions followed over the next 3 months with the last explosive eruption occurring on Oct. 3, 2023. Additional ash-producing explosive eruptions are possible and would likely be preceded by increases in seismic tremor and elevated surface temperatures. 

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network. In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

(12) Volcanic cloud height: NA
(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 10 miles (16 km). A 660 ft. (200 m) wide 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 26 confirmed eruptions since 1824. Most eruptions are relatively small, although the April-May 1999 event generated an ash column that reached 45,000 ft. (14 km) above sea level.

(15) Contacts:

Matt Haney, Scientist-in-Charge, USGS mhaney@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI dfee1@alaska.edu (907) 378-5460

(16) Next Notice:
2023-10-30 - Aniakchak, Aviation Color Code: UNASSIGNED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20231030/2214Z)
(3) Volcano: Aniakchak (VNUM #312090)
(4) Current Color Code: UNASSIGNED
(5) Previous Color Code: GREEN
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2023/A1557
(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 Alaska Volcano Observatory (AVO) has experienced the failure of seismic monitoring equipment at Aniakchak Volcano and the remaining instrumentation is insufficient to establish that the volcano is at a typical background level. It is not possible to repair this equipment until next summer's field season. As a result, AVO is unable to (1) assess whether this volcano may be building towards an eruption and (2) quickly confirm or dismiss reports of activity.

Because this volcano is no longer seismically monitored at adequate levels, the Aviation Color Code and Volcano Alert Level are changed to UNASSIGNED/UNASSIGNED.  As at other volcanoes without real-time seismic networks, AVO will continue to use satellite data, regional seismic, infrasound and lightning networks, and reports from pilots and ground observers to detect signs of eruptive activity.

(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:

Matt Haney, Scientist-in-Charge, USGS mhaney@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.

2023-10-24 - Bogoslof, Aviation Color Code: YELLOW (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20231024/2255Z)
(3) Volcano: Bogoslof (VNUM #311300)
(4) Current Color Code: YELLOW
(5) Previous Color Code: UNASSIGNED
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2023/A1535
(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:

Over the past three days, over 90 earthquakes have been detected in the vicinity of Bogoslof volcano. This marks a change in behavior and the Aviation Color Code and Volcano Alert Level is being increased to YELLOW/ADVISORY. Increases in seismic activity typically precede eruptions, but many volcanoes have exhibited similar behavior that did not result in eruptions. There have been no other signs of unrest observed in satellite data over the past several days.

Bogoslof volcano is monitored using a single local seismic station, distant seismic and infrasound instruments, satellite data and lightning detection.  At least nine historical eruptions have been documented at Bogoslof volcano. The most recent occurred from December 2016 to August 2017 and produced seventy main explosive events that generated volcanic ash clouds that rose as high as 13 km (42,500 ft) above sea level, and that greatly modified the topography of Bogoslof Island.

(12) Volcanic cloud height: None
(13) Other volcanic cloud information: N/A
(14) Remarks:

Bogoslof volcano is located about 98 km (61 mi) northwest of Unalaska/Dutch Harbor, 123 km (76 mi) northeast of Nikolski, and 149 km (93 mi) northeast of Akutan. It is within the U.S. Fish and Wildlife Service Alaska Maritime National Wildlife Refuge and is habitat for marine mammals and seabirds (https://www.fws.gov/refuge/alaska_maritime/).

(15) Contacts:

Chris Waythomas, Acting Scientist-in-Charge, USGS cwaythomas@usgs.gov (907) 786-7497

Jessica Larsen, Acting Coordinating Scientist, UAFGI jflarsen@alaska.edu (907) 378-5460 

(16) Next Notice:
2023-10-15 - Shishaldin, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20231015/2043Z)
(3) Volcano: Shishaldin (VNUM #311360)
(4) Current Color Code: ORANGE
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2023/A1505
(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:

Clear web camera views of Shishaldin from yesterday and today show a robust vapor cloud at the volcano's summit. This vapor plume likely consists primarily of steam and other volcanic gases. The vapor cloud does not indicate that an eruption is in progress and probably reflects the interaction of hot material and snow and ice. The Aviation Color Code remains at ORANGE and the Volcano Alert Level at WATCH. 

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network.  In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

(12) Volcanic cloud height: 10,000 to 20,000 feet above sea level
(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 10 miles (16 km). A 660 ft. (200 m) wide 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 26 confirmed eruptions since 1824. Most eruptions are relatively small, although the April-May 1999 event generated an ash column that reached 45,000 ft. (14 km) above sea level.

(15) Contacts:

Matt Haney, Scientist-in-Charge, USGS mhaney@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI dfee1@alaska.edu (907) 378-5460

(16) Next Notice:
2023-10-13 - Wrangell, Aviation Color Code: UNASSIGNED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20231013/1844Z)
(3) Volcano: Wrangell (VNUM #315020)
(4) Current Color Code: UNASSIGNED
(5) Previous Color Code: GREEN
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2023/A1495
(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:

Due to a station outage, the Alaska Volcano Observatory (AVO) has lost the capability to monitor Mount Wrangell volcano seismically and cannot reliably detect changes in unrest at the volcano. AVO is moving the Volcano Alert Level and Aviation Color Code of Mount Wrangell to UNASSIGNED. As at other Alaska volcanoes, AVO will continue using satellite, regional infrasound, lightning data, and reports from pilots and ground observers to detect signs of eruptive activity should they occur.

(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:

Matt Haney, Scientist-in-Charge, USGS mhaney@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

2023-10-05 - Ruby, Aviation Color Code: UNASSIGNED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20231005/2350Z)
(3) Volcano: Ruby (VNUM #284202)
(4) Current Color Code: UNASSIGNED
(5) Previous Color Code: YELLOW
(6) Source: U.S. Geological Survey
(7) Notice Number: 2023/N196
(8) Volcano Location: N 15 deg 37 min E 145 deg 34 min
(9) Area: Northern Mariana Islands
(10) Summit Elevation: -755 ft (-230 m)
(11) Volcanic Activity Summary:

No sign of new volcanic activity has been detected at Ruby Seamount since September 14 and 15. Since there is no indication of ongoing activity, the Aviation Color Code and Volcano Alert Level are being lowered back to UNASSIGNED, reflecting the lack of nearby monitoring instruments that could detect lower-level events. 

It is possible that further eruptive activity could occur at Ruby. The volcano is monitored by a regional geophysical monitoring network, including a station at Saipan (50 km away) as well as others in Guam, Japan, and an array of underwater pressure sensors at Wake Island. 

Ruby is a submarine volcano that rises to within 230 m of the sea surface near the southern end of the Mariana arc northwest of the island of Saipan. The volcano was first detected in eruption in 1966 by sonar signals. In 1995, submarine explosions were heard, accompanied by a fish kill, sulfurous odors, bubbling water, and the detection of volcanic tremor. 

(12) Volcanic cloud height: none observed
(13) Other volcanic cloud information: none observed
(14) Remarks:
(15) Contacts:

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

(16) Next Notice:
2023-10-03 - Shishaldin, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20231003/1836Z)
(3) Volcano: Shishaldin (VNUM #311360)
(4) Current Color Code: ORANGE
(5) Previous Color Code: RED
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2023/A1463
(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 explosive ash eruption of Shishaldin Volcano that started this morning at 5:50 AKDT (13:50 UTC) has ended. Clear webcam views show steaming at the volcano's summit. The Aviation Color Code is being lowered to ORANGE and the Volcano Alert Level to WATCH. 

Seismic and infrasound activity are diminished but still slightly above background. Volcanic flows on the flanks of the volcano may create lower-level ash emissions. 

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network.  In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

(12) Volcanic cloud height: none observed; low-level ash may be produced from volcanic flows
(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 10 miles (16 km). A 660 ft. (200 m) wide 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 26 confirmed eruptions since 1824. Most eruptions are relatively small, although the April-May 1999 event generated an ash column that reached 45,000 ft. (14 km) above sea level.

(15) Contacts:

Matt Haney, Scientist-in-Charge, USGS mhaney@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI dfee1@alaska.edu (907) 378-5460

(16) Next Notice:
2023-10-03 - Shishaldin, Aviation Color Code: RED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20231003/1731Z)
(3) Volcano: Shishaldin (VNUM #311360)
(4) Current Color Code: RED
(5) Previous Color Code: RED
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2023/A1462
(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 from Shishaldin Volcano continue since starting this morning at 5:50 AKDT (13:50 UTC), but at a lower level of 20,000 to 25,000 ft asl after an initial height of ~40,000 ft asl. Seismicity and infrasound have diminished but are still above background. 

The Aviation Color Code remains at RED and the Volcano Alert Level at WARNING. The National Weather Service has issued a SIGMET for this ash cloud, and a Special Weather Statement has been issued for possible ashfall on Unimak Island and the lower Alaska Peninsula, including False Pass, Cold Bay, and Sand Point. 

Based on previous eruption cycles, significant ash emissions may continue for a few more hours. Pyroclastic and mudflows are likely on the immediate flanks of the volcano.

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network.  In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

(12) Volcanic cloud height: 25,000 ft asl
(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 10 miles (16 km). A 660 ft. (200 m) wide 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 26 confirmed eruptions since 1824. Most eruptions are relatively small, although the April-May 1999 event generated an ash column that reached 45,000 ft. (14 km) above sea level.

(15) Contacts:

Matt Haney, Scientist-in-Charge, USGS mhaney@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI dfee1@alaska.edu (907) 378-5460

(16) Next Notice:
2023-10-03 - Shishaldin, Aviation Color Code: RED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20231003/1412Z)
(3) Volcano: Shishaldin (VNUM #311360)
(4) Current Color Code: RED
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2023/A1461
(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:

An ash cloud from Shishaldin Volcano reaching 40,000 ft (12 km) above sea level was observed in satellite data at 5:20 am AKDT (13:50 UTC). This follows a several-hour increase in observed eruptive activity, and a recent sharp increase in infrasound, seismicity, and lighting detections. In response, the Aviation Color Code is being raised to RED and the Volcano Alert Level is being raised to WARNING. The National Weather Service has issued a SIGMET for this ash cloud. Based on previous eruption cycles, significant ash emissions are likely to continue for several hours. Pyroclastic and mudflows are likely on the immediate flanks of the volcano.

Based on previous eruption cycles, significant ash emissions are likely to continue for several hours. Pyroclastic and mudflows are likely on the immediate flanks of the volcano.

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network.  In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

 

 

 

(12) Volcanic cloud height: Over 40,000 ft (12 km) above sea level
(13) Other volcanic cloud information: Ash plume is drifting south
(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 10 miles (16 km). A 660 ft. (200 m) wide 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 26 confirmed eruptions since 1824. Most eruptions are relatively small, although the April-May 1999 event generated an ash column that reached 45,000 ft. (14 km) above sea level.

(15) Contacts:

Matt Haney, Scientist-in-Charge, USGS mhaney@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI dfee1@alaska.edu (907) 378-5460

(16) Next Notice:
2023-10-03 - Shishaldin, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20231003/0743Z)
(3) Volcano: Shishaldin (VNUM #311360)
(4) Current Color Code: ORANGE
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2023/A1459
(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 at Shishaldin has increased in the last 2 hours with lava fountaining observed. Starting at 9:00 pm AKDT (October 3 05:00 UTC) seismic activity at the volcano began to increase significantly. Around the same time, satellite images showed an increase in surface temperature consistent with lava fountaining, which was confirmed in clear web camera images. This fountaining has produced small hot avalanches of rock and lava down the slope of the volcano, and likely is producing minor ash clouds downwind of the volcano but these have not been large enough to detect in satellite images.

Based on previous eruption cycles, more significant ash emissions are likely to occur, however, the time from initial activity to more significant explosions ranges from hours to over a day.

Recent significant ash events during the current eruption resulted in ash clouds with heights up to 40,000 ft (12 km) above sea level.  These events can occur with little warning. It is also possible that ash emissions may occur at a lower-level, steady state and be sustained for many hours. AVO is monitoring the volcano closely and will issue additional Volcanic Activity Notice’s to provide notice of significant changes in activity as they occur.

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network.  In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

 

 

(12) Volcanic cloud height: Unknown
(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 10 miles (16 km). A 660 ft. (200 m) wide 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 26 confirmed eruptions since 1824. Most eruptions are relatively small, although the April-May 1999 event generated an ash column that reached 45,000 ft. (14 km) above sea level.

(15) Contacts:

Matt Haney, Scientist-in-Charge, USGS mhaney@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI dfee1@alaska.edu (907) 378-5460

(16) Next Notice:
2023-09-25 - Shishaldin, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20230925/2049Z)
(3) Volcano: Shishaldin (VNUM #311360)
(4) Current Color Code: ORANGE
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2023/A1432
(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:

CORRECTION:  The ash cloud from this morning’s eruption detached from the volcano around 07:00 AKDT (15:00 UTC) and is drifting east-southeast at an altitude of 38,000 ft above sea level. 

Activity at Shishaldin Volcano has declined significantly. Seismicity decreased rapidly around 06:00 AKDT (14:00 UTC) and no significant ash emissions from the volcano are being observed in satellite data at this time. In response, AVO is lowering the Aviation Color Code to ORANGE and the Alert Level to WATCH. 

The ash cloud from this morning’s eruption detached from the volcano around 07:00 AKDT (15:00 UTC) and is drifting east-southeast at an altitude of 38,000 ft above sea level.  Ash emissions continued at a lower altitude of about 20,000–25,000 ft above sea level until about 08:20 AKDT (16:20 UTC). Small explosions are currently being detected in infrasound data and likely represent low-level eruptive activity near the vent area.

Trace to minor amounts of ashfall were reported by the communities of False Pass, King Cove, Cold Bay and Sand Point.  Ashfall occurred during rainfall in all four communities. No ashfall is expected from the current small explosions that are being detected in infrasound. Refer to the National Weather Service SIGMET for the drifting ash cloud (https://www.weather.gov/aawu/sigmets) and the Ashfall Advisory and Special Weather Statement for trace to minor amounts of ashfall on communities on the lower Alaska Peninsula and surrounding waters (https://www.weather.gov/afc/).

Based on previous eruption cycles, pyroclastic flows and mudflows are likely on the immediate flanks of the volcano.

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network.  In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

(12) Volcanic cloud height: 9,500 ft above sea level
(13) Other volcanic cloud information: Drifting cloud from the main explosion moving east-southeast of the volcano
(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 10 miles (16 km). A 660 ft. (200 m) wide 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 26 confirmed eruptions since 1824. Most eruptions are relatively small, although the April-May 1999 event generated an ash column that reached 45,000 ft. (14 km) above sea level.

(15) Contacts:

Matt Haney, Scientist-in-Charge, USGS mhaney@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI dfee1@alaska.edu (907) 378-5460

(16) Next Notice:
2023-09-25 - Shishaldin, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20230925/2034Z)
(3) Volcano: Shishaldin (VNUM #311360)
(4) Current Color Code: ORANGE
(5) Previous Color Code: RED
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2023/A1431
(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:

Activity at Shishaldin Volcano has declined significantly. Seismicity decreased rapidly around 06:00 AKDT (14:00 UTC) and no significant ash emissions from the volcano are being observed in satellite data at this time. In response, AVO is lowering the Aviation Color Code to ORANGE and the Alert Level to WATCH. 

The ash cloud from this morning’s eruption detached from the volcano around 07:00 AKDT (15:00 UTC) and is drifting east-southeast at an altitude of 45,000 ft above sea level.  Ash emissions continued at a lower altitude of about 20,000–25,000 ft above sea level until about 08:20 AKDT (16:20 UTC). Small explosions are currently being detected in infrasound data and likely represent low-level eruptive activity near the vent area.

Trace to minor amounts of ashfall were reported by the communities of False Pass, King Cove, Cold Bay and Sand Point.  Ashfall occurred during rainfall in all four communities. No ashfall is expected from the current small explosions that are being detected in infrasound. Refer to the National Weather Service SIGMET for the drifting ash cloud (https://www.weather.gov/aawu/sigmets) and the Ashfall Advisory and Special Weather Statement for trace to minor amounts of ashfall on communities on the lower Alaska Peninsula and surrounding waters (https://www.weather.gov/afc/).

Based on previous eruption cycles, pyroclastic flows and mudflows are likely on the immediate flanks of the volcano.

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network.  In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

(12) Volcanic cloud height: 9,500 ft above sea level
(13) Other volcanic cloud information: Drifting cloud from the main explosion moving east-southeast of the volcano
(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 10 miles (16 km). A 660 ft. (200 m) wide 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 26 confirmed eruptions since 1824. Most eruptions are relatively small, although the April-May 1999 event generated an ash column that reached 45,000 ft. (14 km) above sea level.

(15) Contacts:

Matt Haney, Scientist-in-Charge, USGS mhaney@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI dfee1@alaska.edu (907) 378-5460

(16) Next Notice:
2023-09-25 - Shishaldin, Aviation Color Code: RED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20230925/1509Z)
(3) Volcano: Shishaldin (VNUM #311360)
(4) Current Color Code: RED
(5) Previous Color Code: RED
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2023/A1430
(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:

An ash cloud from Shishaldin Volcano initially reached 45,000 ft (14 km) above sea level starting at 05:42 am AKDT (13:42 UTC). Ash emissions continue but the height is decreasing. Seismic activity dropped sharply along with the start of ash emissions and now is at low levels. The Aviation Color Code remains at RED and the Volcano Alert Level at WARNING. The National Weather Service has issued a SIGMET for this ash cloud, an Ash Advisory has been issued for False Pass, and a Special Weather Statement has been issued for possible trace ash on Cold Bay, King Cove, and Sand Point.

Based on previous eruption cycles, significant ash emissions are likely to continue for several hours. Pyroclastic flows and mudflows are likely on the immediate flanks of the volcano.

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network.  In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

(12) Volcanic cloud height: 45,000 ft. above sea level
(13) Other volcanic cloud information: moving 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 10 miles (16 km). A 660 ft. (200 m) wide 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 26 confirmed eruptions since 1824. Most eruptions are relatively small, although the April-May 1999 event generated an ash column that reached 45,000 ft. (14 km) above sea level.

(15) Contacts:

Matt Haney, Scientist-in-Charge, USGS mhaney@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI dfee1@alaska.edu (907) 378-5460

(16) Next Notice:
2023-09-25 - Shishaldin, Aviation Color Code: RED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20230925/1402Z)
(3) Volcano: Shishaldin (VNUM #311360)
(4) Current Color Code: RED
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2023/A1427
(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:

An ash cloud from Shishaldin Volcano initially reached 45,000 ft (14 km) above sea level starting at 05:42 am AKDT (13:42 UTC). Ash emissions continue but the height is decreasing. Seismic activity dropped sharply along with the start of ash emissions and now is at low levels. The Aviation Color Code remains at RED and the Volcano Alert Level at WARNING. The National Weather Service has issued a SIGMET for this ash cloud, an Ash Advisory has been issued for False Pass, and a Special Weather Statement has been issued for possible trace ash on Cold Bay, King Cove, and Sand Point.

Based on previous eruption cycles, significant ash emissions are likely to continue for several hours. Pyroclastic flows and mudflows are likely on the immediate flanks of the volcano.

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network.  In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

 

 

 

(12) Volcanic cloud height: 45,000 ft. above sea level
(13) Other volcanic cloud information: moving 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 10 miles (16 km). A 660 ft. (200 m) wide 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 26 confirmed eruptions since 1824. Most eruptions are relatively small, although the April-May 1999 event generated an ash column that reached 45,000 ft. (14 km) above sea level.

(15) Contacts:

Matt Haney, Scientist-in-Charge, USGS mhaney@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI dfee1@alaska.edu (907) 378-5460

(16) Next Notice:
2023-09-25 - Shishaldin, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20230925/1325Z)
(3) Volcano: Shishaldin (VNUM #311360)
(4) Current Color Code: ORANGE
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2023/A1428
(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 level of activity at Shishaldin remains high, with increasing seismicity and evidence for lava eruption and volcanic flows. 

Elevated surface temperatures consistent with lava fountaining over the crater rim have been observed during clear conditions overnight. Low-level ash emissions less than 15,000 ft. (4.5 km) above sea level were observed starting at 6 pm AKDT yesterday (02:00 UTC September 25), but these dissipated quickly. Beginning at 12 am AKDT today (08:00 UTC), a series of seismic signals consistent with volcanic flows were recorded on the north side of the volcano. Meteorologic clouds up to 20,000 ft. (6 km) above sea level have obscured view of the volcano since this time, and no ash emissions above this level have been observed.

The current period of heightened seismicity at Shishaldin, which started yesterday morning, has lasted longer than previous events during the 2023 eruption. It remains possible that higher ash emissions will occur along with this increased activity.

Previous recent significant ash events resulted in ash clouds with heights up to 40,000 ft (12 km) above sea level.  These events can occur with little warning. It is also possible that ash emissions may occur at a lower level and be sustained for many hours. AVO is monitoring the volcano closely and will issue additional Volcanic Activity Notices about significant changes in activity as they occur.

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network.  In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

(12) Volcanic cloud height: Not observed currently
(13) Other volcanic cloud information: Any ash emissions remain below 20,000 ft. asl
(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 10 miles (16 km). A 660 ft. (200 m) wide 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 26 confirmed eruptions since 1824. Most eruptions are relatively small, although the April-May 1999 event generated an ash column that reached 45,000 ft. (14 km) above sea level.

(15) Contacts:

Matt Haney, Scientist-in-Charge, USGS mhaney@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI dfee1@alaska.edu (907) 378-5460

(16) Next Notice:
2023-09-25 - Shishaldin, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20230925/0215Z)
(3) Volcano: Shishaldin (VNUM #311360)
(4) Current Color Code: ORANGE
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2023/A1426
(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 level of activity has increased at Shishaldin Volcano. After a prolonged low-level eruption over the past day, a strong increase in seismic tremor over the past hour and continued high temperatures at the volcano observed in satellite data over the past 18 hours suggests that stronger explosive activity is likely imminent. Elevated surface temperatures consistent with lava erupting at the summit are evident in the latest satellite data, but no significant ash emissions have been observed. Based on previous eruption cycles, ash emissions are likely to occur and may increase in the next several hours. 

Recent significant ash events during the current eruption resulted in ash clouds with heights up to 40,000 ft (12 km) above sea level.  These events can occur with little warning. It is also possible that ash emissions may occur at a lower-level, steady state and be sustained for many hours. AVO is monitoring the volcano closely and will issue additional Volcanic Activity Notice’s to provide notice of significant changes in activity as they occur.

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network.  In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

 

 

(12) Volcanic cloud height: None
(13) Other volcanic cloud information: None
(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 10 miles (16 km). A 660 ft. (200 m) wide 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 26 confirmed eruptions since 1824. Most eruptions are relatively small, although the April-May 1999 event generated an ash column that reached 45,000 ft. (14 km) above sea level.

(15) Contacts:

Matt Haney, Scientist-in-Charge, USGS mhaney@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI dfee1@alaska.edu (907) 378-5460

(16) Next Notice:
2023-09-24 - Shishaldin, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20230924/1700Z)
(3) Volcano: Shishaldin (VNUM #311360)
(4) Current Color Code: ORANGE
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2023/A1422
(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:

Geophysical and remote sensing data indicate that low-level eruption at Shishaldin Volcano continues but remains confined to the summit crater. Strongly elevated surface temperatures and some small-amplitude infrasound detections are occuring. Seismic tremor remains high but has started to slowly decline over the past eight hours. No ash emissions or deposits outside the crater have been observed in satellite or web camera imagery. Based on previous eruptive episodes, it remains possible that this activity may culminate in more significant lava fountaining and ash emissions. AVO is monitoring the volcano closely and will issue additional Volcanic Activity Notice’s to provide notice of significant changes in activity as they occur.

Recent significant ash events during the current eruption resulted in ash clouds with heights up to 40,000 ft (12 km) above sea level. These events can occur with little warning. It is also possible that ash emissions may occur at a lower-level, steady state and be sustained for many hours. 

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network. In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

 

 

(12) Volcanic cloud height: None
(13) Other volcanic cloud information: None
(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 10 miles (16 km). A 660 ft. (200 m) wide 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 26 confirmed eruptions since 1824. Most eruptions are relatively small, although the April-May 1999 event generated an ash column that reached 45,000 ft. (14 km) above sea level.

(15) Contacts:

Matt Haney, Scientist-in-Charge, USGS mhaney@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI dfee1@alaska.edu (907) 378-5460

(16) Next Notice:
2023-09-24 - Shishaldin, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20230924/0825Z)
(3) Volcano: Shishaldin (VNUM #311360)
(4) Current Color Code: ORANGE
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2023/A1421
(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:

Seismic tremor remains high at Shishaldin Volcano and nearly continuous small infrasound signals are being detected suggesting that low-level eruptive activity is likely occurring with the summit crater. Based on previous eruptive episodes, this activity may culminate in more significant lava fountaining and ash emissions within hours. However, no strongly elevated temperatures indicative of lava at the surface or ash emissions have accompanied the elevated geophysical data thus far. The volcano is mostly obscured by clouds between 10,000 and 15,000 ft above sea level, which preclude observations of possible low-level activity. AVO is monitoring the volcano closely and will issue additional Volcanic Activity Notice’s to provide notice of significant changes in activity as they occur.

Recent significant ash events during the current eruption resulted in ash clouds with heights up to 40,000 ft (12 km) above sea level. These events can occur with little warning. It is also possible that ash emissions may occur at a lower-level, steady state and be sustained for many hours. 

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network. In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

 

 

(12) Volcanic cloud height: None
(13) Other volcanic cloud information: None
(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 10 miles (16 km). A 660 ft. (200 m) wide 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 26 confirmed eruptions since 1824. Most eruptions are relatively small, although the April-May 1999 event generated an ash column that reached 45,000 ft. (14 km) above sea level.

(15) Contacts:

Matt Haney, Scientist-in-Charge, USGS mhaney@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI dfee1@alaska.edu (907) 378-5460

(16) Next Notice:
2023-09-24 - Shishaldin, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20230924/0211Z)
(3) Volcano: Shishaldin (VNUM #311360)
(4) Current Color Code: ORANGE
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2023/A1420
(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:

Seismic tremor has continued to increase over the day at Shishaldin Volcano and geophysical signals suggest low-level eruptive activity is likely occurring with the summit crater. Based on previous episodes of activity, this activity may culminate in more significant lava fountaining and ash emissions within hours. However, no strongly elevated temperatures indicative of lava at the surface or ash emissions have accompanied the elevated seismicity thus far. The volcano is mostly obscured by clouds between 2,000 and 15,000 ft above sea level, which preclude observations of possible low-level activity. However, regional infrasound sensors have detected some signals from the direction of Shishaldin that suggest minor eruptive activity within the summit crater may been occurring. If geophysical or remote sensing signals intensify or a significant eruption begins, the Alaska Volcano Observatory will issue further notices of volcanic activity. 

Recent significant ash events during the current eruption resulted in ash clouds with heights up to 40,000 ft (12 km) above sea level. These events can occur with little warning. It is also possible that ash emissions may occur at a lower-level, steady state and be sustained for many hours. AVO is monitoring the volcano closely and will issue additional Volcanic Activity Notice’s to provide notice of significant changes in activity as they occur.

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network. In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

 

 

(12) Volcanic cloud height: None
(13) Other volcanic cloud information: None
(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 10 miles (16 km). A 660 ft. (200 m) wide 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 26 confirmed eruptions since 1824. Most eruptions are relatively small, although the April-May 1999 event generated an ash column that reached 45,000 ft. (14 km) above sea level.

(15) Contacts:

Matt Haney, Scientist-in-Charge, USGS mhaney@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI dfee1@alaska.edu (907) 378-5460

(16) Next Notice:
2023-09-23 - Shishaldin, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20230923/2028Z)
(3) Volcano: Shishaldin (VNUM #311360)
(4) Current Color Code: ORANGE
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2023/A1415
(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 level of unrest has increased at Shishaldin Volcano. Seismic tremor has increased significantly over the past 36 hours. No strongly elevated temperatures indicative of lava at the surface or ash emissions have accompanied the elevated seismicity at this time, although the volcano is obscured by clouds. Based on previous episodes of activity, eruptive activity in the form of lava fountaining and ash emissions is possible within hours. If geophysical or remote sensing signals intensify, the Alaska Volcano Observatory will issue further notices of volcanic activity. 

Recent significant ash events during the current eruption resulted in ash clouds with heights up to 40,000 ft (12 km) above sea level. These events can occur with little warning. It is also possible that ash emissions may occur at a lower-level, steady state and be sustained for many hours. AVO is monitoring the volcano closely and will issue additional Volcanic Activity Notice’s to provide notice of significant changes in activity as they occur.

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network. In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

 

 

(12) Volcanic cloud height: None
(13) Other volcanic cloud information: None
(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 10 miles (16 km). A 660 ft. (200 m) wide 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 26 confirmed eruptions since 1824. Most eruptions are relatively small, although the April-May 1999 event generated an ash column that reached 45,000 ft. (14 km) above sea level.

(15) Contacts:

Matt Haney, Scientist-in-Charge, USGS mhaney@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI dfee1@alaska.edu (907) 378-5460

(16) Next Notice:
2023-09-19 - Ruby, Aviation Color Code: YELLOW (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20230919/0306Z)
(3) Volcano: Ruby (VNUM #284202)
(4) Current Color Code: YELLOW
(5) Previous Color Code:
(6) Source: U.S. Geological Survey
(7) Notice Number: 2023/N180
(8) Volcano Location: N 15 deg 37 min E 145 deg 34 min
(9) Area: Northern Mariana Islands
(10) Summit Elevation: -755 ft (-230 m)
(11) Volcanic Activity Summary:

Analysis of seismoacoustic signals and observations of a submarine plume in satellite imagery are consistent with an eruption at Ruby seamount beginning the morning of September 15 ChST. Satellite imagery shows a submarine plume of discolored water by sunrise at ~20:50 UTC on September 14 (06:50 ChST September 15). This plume does not breach the ocean surface. Onset of the eruption prior to the plume detection is not observed in geophysical data. Retrospective analysis of seismoacoustic data from a geophysical monitoring station on Saipan, 50 km to the southeast of the volcano, capture eruption signals beginning at 14:27 ChST on September 15 (04:27 UTC). The activity was also picked up on other regional geophysical monitoring networks in the Pacific. The plume is detached in satellite imagery by the morning of September 16 and no activity has since been observed on geophysical networks. Due to this activity at Ruby, the Aviation Color Code and Volcano Alert Level are being raised to YELLOW/ADVISORY.

It is possible that further eruptive activity could occur at Ruby. The volcano is monitored by a regional geophysical monitoring network, including a station at Saipan (50 km away) as well as others in Guam, Japan, and an underwater pressure sensor at Wake Island. Analysis of the geophsyical data was done in collaboration with the Laboratoire de Geophysique in Tahiti.

Ruby is a submarine volcano that rises to within 230 m of the sea surface near the southern end of the Mariana arc northwest of the island of Saipan. The volcano was first detected in eruption in 1966 by sonar signals. In 1995, submarine explosions were heard, accompanied by a fish kill, sulfurous odors, bubbling water, and the detection of volcanic tremor.

(12) Volcanic cloud height: 0 ft, submarine
(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 (907) 786-7497
http://volcano.wr.usgs.gov/cnmistatus.php

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

(16) Next Notice:
2023-09-17 - Kilauea, Aviation Color Code: YELLOW (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20230917/1902Z)
(3) Volcano: Kilauea (VNUM #332010)
(4) Current Color Code: YELLOW
(5) Previous Color Code: ORANGE
(6) Source: Hawaiian Volcano Observatory
(7) Notice Number: 2023/H317
(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:

The eruption that began at Kīlauea summit on September 10 has ended. Lava supply to the vents on the downdropped block in Kīlauea 's summit caldera ceased yesterday, September 16, based upon visual and geophysical observations. Sulfur dioxide (SO2) 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.  

During the morning of September 16, HVO field crews reported that active lava was no longer flowing onto Halemaʻumaʻu crater floor and was restricted to a ponded area north of the vents on the downdropped block. They observed lava spattering at the vents cease at approximately 11:15 am yesterday, September 16, and webcam views show the ponded lava stagnant by around noon. Overnight webcam views showed incandescence across the eruption area as lava erupted over the past week continues to cool. These observations are supported by geophysical data which shows that eruptive tremor (a signal associated with fluid movement) in the summit region decreased over September 15 and 16 and returned to pre-eruption levels by 5 p.m. HST on September 16. Over that period, mild inflation has been recorded at summit tiltmeters. Sulfur dioxide (SO2) emissions have also decreased to near background levels, and were measured at a rate of 800 tonnes per day yesterday, September 16.

More eruption information on the September 2023 Kīlauea summit eruption is available at: https://www.usgs.gov/volcanoes/kilauea/recent-eruption

There remains the potential for eruptive activity to resume in the near future at or near the summit of Kīlauea with little or no warning.

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

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 volcano alert levels and 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. 

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. 

(15) Contacts:

askHVO@usgs.gov

(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:

2023-09-16 - Shishaldin, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20230916/0844Z)
(3) Volcano: Shishaldin (VNUM #311360)
(4) Current Color Code: ORANGE
(5) Previous Color Code: RED
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2023/A1393
(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:

Activity at Shishaldin Volcano has declined. Seismicity decreased rapidly around 6:30 pm AKDT Sept. 15  (4:30 UTC, Sept. 16) yet remained elevated until 9:00 p.m. AKDT.  During this period of waning seismicity, volcanic lightning continued to be detected, indicating continued ash production.  The last detection of volcanic lighting was at 8:48 p.m. AKDT and seismicity has returned to pre-eruptive levels, indicating that significant ash emissions have ended. Thus, the Aviation Color Code and Volcano Alert Level are being decreased to ORANGE/WATCH.

Trace ash fall was reported in the community of False Pass between 18:00 and 20:30 AKDT (0200 to 0430 UTC). The National Weather Service has issued a SIGMET for the drifting ash cloud, and a Special Weather Statement has been issued for trace ash on False Pass.

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network.  In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

 

 

 

(12) Volcanic cloud height: Unknown
(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 10 miles (16 km). A 660 ft. (200 m) wide 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 26 confirmed eruptions since 1824. Most eruptions are relatively small, although the April-May 1999 event generated an ash column that reached 45,000 ft. (14 km) above sea level.

(15) Contacts:

Matt Haney, Scientist-in-Charge, USGS mhaney@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI dfee1@alaska.edu (907) 378-5460

(16) Next Notice:
2023-09-16 - Shishaldin, Aviation Color Code: RED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20230916/0524Z)
(3) Volcano: Shishaldin (VNUM #311360)
(4) Current Color Code: RED
(5) Previous Color Code: RED
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2023/A1392
(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 explosive eruption at Shishaldin Volcano continues, but has decreased in intensity. An explosive event began at 5:10 p.m. AKDT on September 15, 2023 (01:10 UTC on Sept 16) after a period of rapidly increasing seismicity. The explosive event produced an ash-rich cloud that the National Weather Service estimated reached an altitude of 42,000 ft  (12.8 km) above sea level and was accompanied by volcanic lightning.

This upper level cloud detached from the vent around 18:30 AKDT (0230 UTC) and is drifting towards the east. Seismicity began to decrease dramaticially at about this same time. Beginning around 19:30 AKDT (0330 UTC), lightning resumed indicating continued ash emssions. The meterological cloud deck over the volcano is currently at about 22,500 ft (6.8 km) above sea level and ash emissions are not visible in satellite data. Explosions continue to be detected in infrasound data, at a lower level than during the most energetic phase of this event. Seismicity is lower, it has not reached its pre-event levels and the Aviation Color Code and Volcano Alert Level remain at RED/WARNING.

Trace ash fall was reported in the community of False Pass between 18:00 and 20:30 AKDT (0200 to 0430 UTC). The National Weather Service has issued a SIGMET for the drifting ash cloud, and a Special Weather Statement has been issued for trace ash on False Pass.

Based on previous eruption cycles, significant ash emissions are likely to continue for several hours. Pyroclastic and mudflows are likely on the immediate flanks of the volcano.

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network.  In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

 

 

 

(12) Volcanic cloud height: Less than 22,000 ft.
(13) Other volcanic cloud information: Ash emission likely based on infrasound, seismic and lightning data.
(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 10 miles (16 km). A 660 ft. (200 m) wide 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 26 confirmed eruptions since 1824. Most eruptions are relatively small, although the April-May 1999 event generated an ash column that reached 45,000 ft. (14 km) above sea level.

(15) Contacts:

Matt Haney, Scientist-in-Charge, USGS mhaney@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI dfee1@alaska.edu (907) 378-5460

(16) Next Notice:
2023-09-16 - Shishaldin, Aviation Color Code: RED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20230916/0141Z)
(3) Volcano: Shishaldin (VNUM #311360)
(4) Current Color Code: RED
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2023/A1391
(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:

An explosive eruption from Shishaldin began around 5:10 p.m. AKDT on September 15, 2023 (01:10 UTC on Sept 16) following a several-hour increase in seismicity.  Ash is currently being produced and is drifting to the east below the cloud deck of 27,000 ft above sea level. The Aviation Color Code and Volcano Alert Level is being raised to RED/WARNING.

Recent significant ash events during the current eruption resulted in ash clouds with heights up to 40,000 ft (12 km) above sea level.  These events can occur with little warning. It is also possible that ash emissions may occur at a lower-level, steady state and be sustained for many hours. AVO is monitoring the volcano closely and will issue additional Volcanic Activity Notice’s to provide notice of significant changes in activity as they occur.

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network.  In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

 

 

(12) Volcanic cloud height: Unknown
(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 10 miles (16 km). A 660 ft. (200 m) wide 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 26 confirmed eruptions since 1824. Most eruptions are relatively small, although the April-May 1999 event generated an ash column that reached 45,000 ft. (14 km) above sea level.

(15) Contacts:

Matt Haney, Scientist-in-Charge, USGS mhaney@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI dfee1@alaska.edu (907) 378-5460

(16) Next Notice:
2023-09-15 - Shishaldin, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20230915/2252Z)
(3) Volcano: Shishaldin (VNUM #311360)
(4) Current Color Code: ORANGE
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2023/A1390
(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 level of unrest is increasing at Shishaldin Volcano. Seismic tremor has intensified over the past 6 hours and, during Shishaldin's ongoing eruptive period, this has often been followed by ash-producing explosive activity over the next several hours. 

Recent significant ash events during the current eruption resulted in ash clouds with heights up to 40,000 ft (12 km) above sea level.  These events can occur with little warning. It is also possible that ash emissions may occur at a lower-level, steady state and be sustained for many hours. AVO is monitoring the volcano closely and will issue additional Volcanic Activity Notice’s to provide notice of significant changes in activity as they occur.

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network.  In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

 

 

(12) Volcanic cloud height: Unknown
(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 10 miles (16 km). A 660 ft. (200 m) wide 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 26 confirmed eruptions since 1824. Most eruptions are relatively small, although the April-May 1999 event generated an ash column that reached 45,000 ft. (14 km) above sea level.

(15) Contacts:

Matt Haney, Scientist-in-Charge, USGS mhaney@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI dfee1@alaska.edu (907) 378-5460

(16) Next Notice:
2023-09-14 - Shishaldin, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20230914/1934Z)
(3) Volcano: Shishaldin (VNUM #311360)
(4) Current Color Code: ORANGE
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2023/A1386
(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:

Following the eruptive activity at Shishaldin Volcano overnight, the level of unrest has reduced significantly. Seismicity declined starting about 7:30 AKDT (15:30 UTC) and remains at low levels. No ash emissions were observed during the period of elevated seismicity overnight, but high clouds were present and could have obscured low-level ash emissions.  

AVO is monitoring the volcano closely and will issue additional Volcanic Activity Notice’s to provide notice of significant changes in activity as they occur.

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network.  In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

 

 

(12) Volcanic cloud height: none observed
(13) Other volcanic cloud information: non observed
(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 10 miles (16 km). A 660 ft. (200 m) wide 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 26 confirmed eruptions since 1824. Most eruptions are relatively small, although the April-May 1999 event generated an ash column that reached 45,000 ft. (14 km) above sea level.

(15) Contacts:

Matt Haney, Scientist-in-Charge, USGS mhaney@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI dfee1@alaska.edu (907) 378-5460

(16) Next Notice:
2023-09-14 - Shishaldin, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20230914/0958Z)
(3) Volcano: Shishaldin (VNUM #311360)
(4) Current Color Code: ORANGE
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2023/A1382
(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 level of unrest has slowly increased at Shishaldin Volcano. A steady increase in seismic tremor over the past 7 hours suggests that explosive activity is likely.  Cloud cover is currently obscuring satellite views of the volcano. Web camera views show incandescent lava at the summit. Based on previous eruption cycles, ash emissions are likely to occur over the next several hours. 

Recent significant ash events during the current eruption resulted in ash clouds with heights up to 40,000 ft (12 km) above sea level.  These events can occur with little warning. It is also possible that ash emissions may occur at a lower-level, steady state and be sustained for many hours. AVO is monitoring the volcano closely and will issue additional Volcanic Activity Notice’s to provide notice of significant changes in activity as they occur.

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network.  In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

 

 

(12) Volcanic cloud height: Unknown
(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 10 miles (16 km). A 660 ft. (200 m) wide 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 26 confirmed eruptions since 1824. Most eruptions are relatively small, although the April-May 1999 event generated an ash column that reached 45,000 ft. (14 km) above sea level.

(15) Contacts:

Matt Haney, Scientist-in-Charge, USGS mhaney@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI dfee1@alaska.edu (907) 378-5460

(16) Next Notice:
2023-09-11 - Kilauea, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20230911/1810Z)
(3) Volcano: Kilauea (VNUM #332010)
(4) Current Color Code: ORANGE
(5) Previous Color Code: RED
(6) Source: Hawaiian Volcano Observatory
(7) Notice Number: 2023/H310
(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:

The eruption within Kīlauea's summit caldera that began yesterday afternoon continues, with eruptive activity confined to the downdropped block and Halemaʻumaʻu crater. HVO is lowering Kīlauea’s volcano alert level from WARNING to WATCH because the style of eruption and fissure location have stabilized, the initial extremely high effusion rates have declined, and no infrastructure is threatened.  Associated hazards are confined to the closed area established by Hawaiʻi Volcanoes National Park.

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. The eruption plume, composed largely of sulfur dioxide and minor volcanic particles, continues to rise to the base of the inversion level at about 8,000-10,000 feet (2,400-3,000 meters) above sea level.  The plume concentration has decreased some due to the drop in effusion rate, but still remains high.  Hazards associated with the eruption are limited and are described below. 

Kīlauea’s summit eruption is expected to continue and remain confined to Kīlauea caldera 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 will continue to monitor this activity closely and report any significant changes in future notices.

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

For more information about the meaning of volcano alert levels and 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: 

The eruption at Kīlauea’s summit is occurring within a closed area of Hawai'i Volcanoes National Park. High levels of volcanic gas—primarily water vapor (H2O), carbon dioxide (CO2), and sulfur dioxide (SO2)—are the primary hazard of concern, as this hazard can have far-reaching effects down-wind. As SO2 is continuously released from the summit during the eruption, it will react in the atmosphere to create the visible haze known as vog (volcanic smog) downwind of Kīlauea. 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 and visitors 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 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. 

(15) Contacts:

askHVO@usgs.gov

(16) Next Notice:

Kīlauea updates will  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:

2023-09-11 - Kilauea, Aviation Color Code: RED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20230911/0118Z)
(3) Volcano: Kilauea (VNUM #332010)
(4) Current Color Code: RED
(5) Previous Color Code: ORANGE
(6) Source: Hawaiian Volcano Observatory
(7) Notice Number: 2023/H274
(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 3:15 a.m./p.m. HST on September 10, 2023, the USGS Hawaiian Volcano Observatory observed eruptive activity in Kīlauea summit webcam images and from field reports indicating that an eruption has commenced within Halemaʻumaʻu crater and on the down dropped block to the east in Kīlauea’s summit caldera, within Hawai‘i Volcanoes National Park.  The eruption was preceded by a period of strong seismicity and rapid uplift of the summit

The USGS Hawaiian Volcano Observatory is elevating Kīlauea’s volcano alert level from WATCH to WARNING and its aviation color code from ORANGE to RED as this eruption and associated hazards are evaluated.  

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.

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

For more information about the meaning of volcano alert levels and 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: 

The eruption at Kīlauea’s summit is occurring within a closed area of Hawai'i Volcanoes National Park. High levels of volcanic gas—primarily water vapor (H2O), carbon dioxide (CO2), and sulfur dioxide (SO2)—are the primary hazard of concern, as this hazard can have far-reaching effects down-wind. As SO2 is continuously released from the summit during the eruption, it will react in the atmosphere to create the visible haze known as vog (volcanic smog) downwind of Kīlauea. 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 and visitors 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 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. 

(15) Contacts:

askHVO@usgs.gov

(16) Next Notice:

Kīlauea updates will  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:

2023-09-11 - Kilauea, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20230911/0052Z)
(3) Volcano: Kilauea (VNUM #332010)
(4) Current Color Code: ORANGE
(5) Previous Color Code: YELLOW
(6) Source: Hawaiian Volcano Observatory
(7) Notice Number: 2023/H271
(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 the afternoon of September 10, 2023, indicating movement of magma in the subsurface.

The USGS Hawaiian Volcano Observatory is raising the volcano alert level/aviation color code for Kīlauea from ADVISORY/YELLOW to WATCH/ORANGE due to this activity.

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. Based on patterns of earthquake activity and ground deformation, it is likely that any new eruptive activity will occur in or near Halemaʻumaʻu crater, within the closed area of Hawaiʻi Volcanoes National Park. 

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.

 

 

(12) Volcanic cloud height: N/A
(13) Other volcanic cloud information: N/A
(14) Remarks:

Hazard Analysis: 

Kīlauea summit eruptive activity over the past several years has occurred at the base of Halemaʻumaʻu crater, within the closed area of Hawaiʻi Volcanoes National Park. During Kīlauea summit eruptions, the high level of volcanic gas—primarily water vapor (H2O), carbon dioxide (CO2), and sulfur dioxide (SO2)—being emitted is the primary hazard of concern, as this hazard can have far-reaching effects downwind. Passive volcanic degassing can occur from within Halemaʻumaʻu crater even during periods of no eruptive activity. As SO2 is released from the summit, it reacts in the atmosphere to create the visible haze known as vog (volcanic smog) that has been observed downwind of Kīlauea. Vog creates the potential for airborne health hazards to residents and visitors, damages agricultural crops and other plants, and affects livestock. For more information on gas hazards at the summit of Kīlauea, please see: https://pubs.er.usgs.gov/publication/fs20173017. Vog information can be found at https://vog.ivhhn.org.  

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

Please see the Hawaiʻi Volcanoes National Park website for visitor information: https://www.nps.gov/havo/index.htm. 

(15) Contacts:

askHVO@usgs.gov

(16) Next Notice:

Kīlauea updates will continue to 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:

2023-09-05 - Shishaldin, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20230905/2214Z)
(3) Volcano: Shishaldin (VNUM #311360)
(4) Current Color Code: ORANGE
(5) Previous Color Code: RED
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2023/A1361
(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:

Activity at Shishaldin Volcano has declined. Web camera observations through 1:30 pm AKDT (21:30 UTC) show that significant ash emissions have ended. Seismicity decreased rapidly around 12:30 pm AKDT (20:30 UTC) and remains low. Thus, the Aviation Color Code and Volcano Alert Level are being decreased to ORANGE/WATCH.

The National Weather Service has issued a SIGMET for the ash cloud (https://www.weather.gov/aawu/sigmets), and a Special Weather Statement and a Marine Weather Statement has been issued for possible trace ash fall on Unimak Island and on nearby marine waters, respectively.

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network.  In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

(12) Volcanic cloud height: 20,000 ft - 25,000 ft
(13) Other volcanic cloud information: Estimate based on winds and satellite obs.
(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 10 miles (16 km). A 660 ft. (200 m) wide 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 26 confirmed eruptions since 1824. Most eruptions are relatively small, although the April-May 1999 event generated an ash column that reached 45,000 ft. (14 km) above sea level.

(15) Contacts:

Matt Haney, Scientist-in-Charge, USGS mhaney@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI dfee1@alaska.edu (907) 378-5460

(16) Next Notice:
2023-09-05 - Shishaldin, Aviation Color Code: RED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20230905/2046Z)
(3) Volcano: Shishaldin (VNUM #311360)
(4) Current Color Code: RED
(5) Previous Color Code: RED
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2023/A1360
(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:

Correction to previous VAN/VONA issued at 12:31 PM AKDT. Alert Level remains at WARNING. 

An explosive eruption from Shishaldin began at ~08:30 AKDT (1630 UTC) following a several-hour increase in seismicity and produced an extensive ash cloud that moved towards the south-southeast at an estimated altitude of 32,000 ft (9.7 km) above sea level. Around 19:00 AKDT (1900 UTC) seismic amplitude decreased rapidly, and the altitude of the ash emissions as observed by satellite also decreased to an estimated altitude of ~15,000 ft (4.5 km). At 12:00 pm AKDT (2000 UTC), the lower-altitude ash cloud extended for ~75 miles (125 km) towards the east. The Aviation Color Code and Volcano Alert Level remains at RED/WARNING.

The National Weather Service has issued a SIGMET for the ash cloud (https://www.weather.gov/aawu/sigmets), and a Special Weather Statement and a Marine Weather Statement has been issued for possible trace ash fall on Unimak Island and on nearby marine waters, respectively. 

Based on previous eruption cycles, significant ash emissions are likely to continue for several hours. Pyroclastic and mudflows are likely on the immediate flanks of the volcano.

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network.  In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

(12) Volcanic cloud height: 15,000 ft
(13) Other volcanic cloud information: Estimate based on winds and satellite obs.
(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 10 miles (16 km). A 660 ft. (200 m) wide 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 26 confirmed eruptions since 1824. Most eruptions are relatively small, although the April-May 1999 event generated an ash column that reached 45,000 ft. (14 km) above sea level.

(15) Contacts:

Matt Haney, Scientist-in-Charge, USGS mhaney@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI dfee1@alaska.edu (907) 378-5460

(16) Next Notice:
2023-09-05 - Shishaldin, Aviation Color Code: RED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20230905/2031Z)
(3) Volcano: Shishaldin (VNUM #311360)
(4) Current Color Code: RED
(5) Previous Color Code: RED
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2023/A1358
(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:

An explosive eruption from Shishaldin began at ~08:30 AKDT (1630 UTC) following a several-hour increase in seismicity and produced an extensive ash cloud that moved towards the south-southeast at an estimated altitude of 32,000 ft (9.7 km) above sea level. Around 19:00 AKDT (1900 UTC) seismic amplitude decreased rapidly, and the altitude of the ash emissions as observed by satellite also decreased to an estimated altitude of ~15,000 ft (4.5 km). At 12:00 pm AKDT (2000 UTC), the lower-altitude ash cloud extended for ~75 miles (125 km) towards the east. The Aviation Color Code and Volcano Alert Level remains at RED/WARNING.

The National Weather Service has issued a SIGMET for the ash cloud (https://www.weather.gov/aawu/sigmets), and a Special Weather Statement and a Marine Weather Statement has been issued for possible trace ash fall on Unimak Island and on nearby marine waters, respectively. 

Based on previous eruption cycles, significant ash emissions are likely to continue for several hours. Pyroclastic and mudflows are likely on the immediate flanks of the volcano.

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network.  In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

(12) Volcanic cloud height: 15,000 ft
(13) Other volcanic cloud information: Estimate based on winds and satellite obs.
(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 10 miles (16 km). A 660 ft. (200 m) wide 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 26 confirmed eruptions since 1824. Most eruptions are relatively small, although the April-May 1999 event generated an ash column that reached 45,000 ft. (14 km) above sea level.

(15) Contacts:

Matt Haney, Scientist-in-Charge, USGS mhaney@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI dfee1@alaska.edu (907) 378-5460

(16) Next Notice:
2023-09-05 - Shishaldin, Aviation Color Code: RED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20230905/1701Z)
(3) Volcano: Shishaldin (VNUM #311360)
(4) Current Color Code: RED
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2023/A1356
(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:

An ash cloud from Shishaldin Volcano reaching 25,000 ft (7.3 km) above sea level and rising was reported by a pilot at at 8:42 am AKDT (1642 UTC). Satellite data suggests that the cloud may be as high as 30,000 ft above sea level (9.1 km). This follows a several-hour increase in seismicity. In response, the Aviation Color Code is being raised to RED and the Volcano Alert Level is being raised to WARNING. The cloud is visible in satellite data moving towards the southeast and lightning associated with the ash cloud has been detected. 

Based on previous eruption cycles, significant ash emissions are likely to continue for several hours. Pyroclastic and mudflows are likely on the immediate flanks of the volcano.

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network.  In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

 

 

 

(12) Volcanic cloud height: 30,000 ft
(13) Other volcanic cloud information: PIREP and satellite data
(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 10 miles (16 km). A 660 ft. (200 m) wide 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 26 confirmed eruptions since 1824. Most eruptions are relatively small, although the April-May 1999 event generated an ash column that reached 45,000 ft. (14 km) above sea level.

(15) Contacts:

Matt Haney, Scientist-in-Charge, USGS mhaney@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI dfee1@alaska.edu (907) 378-5460

(16) Next Notice:
2023-08-26 - Shishaldin, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20230826/0831Z)
(3) Volcano: Shishaldin (VNUM #311360)
(4) Current Color Code: ORANGE
(5) Previous Color Code: RED
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2023/A1320
(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:

Satellite observations through 1200 am AKDT (0800 UTC) show that ash emissions have ended. Seismicity decreased rapidly around 5:30 pm AKDT (0130 UTC on 26 August) and remains low. Thus, the Avation Color Code and Volcano Alert Level are being decreased to ORANGE/WATCH. 

The National Weather Service is responsible for tracking the drifting ash cloud and SIGMETs have been issued today and will continue until the cloud disperses. See https://www.weather.gov/aawu/SIGMETs for current information for aviation.

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network.  In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

 

(12) Volcanic cloud height: n/a
(13) Other volcanic cloud information: Satellite data show ash emissions have ended.
(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 10 miles (16 km). A 660 ft. (200 m) wide 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 26 confirmed eruptions since 1824. Most eruptions are relatively small, although the April-May 1999 event generated an ash column that reached 45,000 ft. (14 km) above sea level.

(15) Contacts:

Matt Haney, Scientist-in-Charge, USGS mhaney@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI dfee1@alaska.edu (907) 378-5460

(16) Next Notice:
2023-08-26 - Shishaldin, Aviation Color Code: RED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20230826/0420Z)
(3) Volcano: Shishaldin (VNUM #311360)
(4) Current Color Code: RED
(5) Previous Color Code: RED
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2023/A1319
(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:

Explosive eruptive activity is continuing at Shishaldin Volcano. An ash cloud continues to be observed in satellite data at an altitude of 21,000 ft (6.4 km) above sea level moving towards the northeast. This is a decrease in altitude from earlier today. Seismic tremor decreased rapidly around 5:30 pm AKDT (0130 UTC) and is approaching levels observed prior to the onset of ash emissions.

Based on previous eruption cycles, it is likley that ash emissions are starting to decrease and may end over the next few hours. Pyroclastic and mudflows are likely on the immediate flanks of the volcano. Minor to trace amounts of ash fall are likely to the north of the volcano and in the water immediately offshore. No ash fall is expected in populated areas.

The National Weather Service is responsible for tracking the drifting ash cloud and SIGMETs have been issued throughout the day. See https://www.weather.gov/aawu/SIGMETs for current information for aviation.

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network.  In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

 

(12) Volcanic cloud height: 21,000 ft msl
(13) Other volcanic cloud information: Observed in satellite data moving northeast
(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 10 miles (16 km). A 660 ft. (200 m) wide 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 26 confirmed eruptions since 1824. Most eruptions are relatively small, although the April-May 1999 event generated an ash column that reached 45,000 ft. (14 km) above sea level.

(15) Contacts:

Matt Haney, Scientist-in-Charge, USGS mhaney@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI dfee1@alaska.edu (907) 378-5460

(16) Next Notice:
2023-08-26 - Shishaldin, Aviation Color Code: RED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20230826/0132Z)
(3) Volcano: Shishaldin (VNUM #311360)
(4) Current Color Code: RED
(5) Previous Color Code: RED
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2023/A1318
(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:

Explosive eruptive activity is continuing at Shishaldin Volcano. An ash cloud rising to about 30,000 ft (9 km) above sea level and extending roughly 280 miles (450 km) northeast of the volcano is evident in satellite data. A SIGMET for this ash cloud has been issued. Seismic tremor increased this afternoon and peaked around 4:30 pm Alaska time (00:30 UTC). The tremor has since dropped but remains elevated.

Based on previous eruption cycles, significant ash emissions are likely to continue for the next few hours. Pyroclastic and mudflows are likely on the immediate flanks of the volcano.

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network.  In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

 

(12) Volcanic cloud height: Drifting at about 30,000 ft (9 km) above sea level.
(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 10 miles (16 km). A 660 ft. (200 m) wide 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 26 confirmed eruptions since 1824. Most eruptions are relatively small, although the April-May 1999 event generated an ash column that reached 45,000 ft. (14 km) above sea level.

(15) Contacts:

Matt Haney, Scientist-in-Charge, USGS mhaney@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI dfee1@alaska.edu (907) 378-5460

(16) Next Notice:
2023-08-25 - Shishaldin, Aviation Color Code: RED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20230825/2004Z)
(3) Volcano: Shishaldin (VNUM #311360)
(4) Current Color Code: RED
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2023/A1317
(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:

An ash cloud from Shishaldin Volcano reaching 28,000 ft (8.5 km) has been reported by aircraft in the vicinity of the volcano. This follows a several-hour increase in seismic activity. In response, the Aviation Color Code is being raised to RED and the Volcano Alert Level is being raised to WARNING.

Based on previous eruption cycles, significant ash emissions are likely to continue for several hours. Pyroclastic and mudflows are likely on the immediate flanks of the volcano.

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network.  In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

 

 

 

(12) Volcanic cloud height: 30,000 ft. (9 km) above sea level
(13) Other volcanic cloud information: lower plume driving NE, higher plume E
(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 10 miles (16 km). A 660 ft. (200 m) wide 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 26 confirmed eruptions since 1824. Most eruptions are relatively small, although the April-May 1999 event generated an ash column that reached 45,000 ft. (14 km) above sea level.

(15) Contacts:

Matt Haney, Scientist-in-Charge, USGS mhaney@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI dfee1@alaska.edu (907) 378-5460

(16) Next Notice:
2023-08-25 - Shishaldin, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20230825/1936Z)
(3) Volcano: Shishaldin (VNUM #311360)
(4) Current Color Code: ORANGE
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2023/A1316
(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 level of unrest has increased at Shishaldin Volcano. Seismic tremor began to increase at around 03:00 this morning Alaska time (11:00 UTC) and is escalating. Elevated surface temperatures consistent with lava erupting at the summit are evident in the latest satellite data. Local infrasound data suggests low-level explosions are occurring. Based on previous eruption cycles over the past month, ash emissions are likely over the next few hours. 

There have been seven significant explosive events during the current eruption. These have resulted in ash clouds with heights up to 40,000 ft (12 km) above sea level and pyroclastic deposits near the volcano.  These events can occur with little warning. It is also possible that ash emissions may occur at a lower-level, steady state and be sustained for many hours. AVO is monitoring the volcano closely and will issue additional Volcanic Activity Notice’s to provide updates of significant changes in activity as they occur.

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network. In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

 

 

(12) Volcanic cloud height: Unknown
(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 10 miles (16 km). A 660 ft. (200 m) wide 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 26 confirmed eruptions since 1824. Most eruptions are relatively small, although the April-May 1999 event generated an ash column that reached 45,000 ft. (14 km) above sea level.

(15) Contacts:

Matt Haney, Scientist-in-Charge, USGS mhaney@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI dfee1@alaska.edu (907) 378-5460

(16) Next Notice:
2023-08-25 - Cleveland, Aviation Color Code: GREEN (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20230825/1806Z)
(3) Volcano: Cleveland (VNUM #311240)
(4) Current Color Code: GREEN
(5) Previous Color Code: YELLOW
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2023/A1311
(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 decrease in seismic activity at Mount Cleveland over the past few weeks to background levels has prompted the Alaska Volcano Observatory to downgrade the Aviation Color Code and Volcano Alert Level from YELLOW/ADVISORY to GREEN/NORMAL.

An increase in the number of small earthquakes near Mount Cleveland in mid-July 2023 prompted raising the Aviation Color Code and Volcano Alert Level from UNASSIGNED/UNASSIGNED to YELLOW/ADVISORY on July 19. This activity  continued for the next several weeks but has since declined. Slightly elevated surface temperatures and weak gas emissions from the summit crater continue to be observed occasionally, but this is not unusual for Mount Cleveland.

The last eruptive activity at Mount Cleveland was a short-lived explosion during the evening (local time) of June 1, 2020. Despite the current pause, the eruptive period at Mount Cleveland, dating back to 2001, remains ongoing and future explosions are likely. These have occurred 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.

Mount Cleveland is currently monitored with a five-station real-time seismic network. We now have enough stations at the volcano to locate volcanic earthquakes thanks to a partnership between AVO and the AVERT (Anticipating Volcanic Eruptions in Real-Time) project at Columbia University. Based on past events, explosive eruptions of Cleveland may occur with little or no warning. 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:

Matt Haney, Scientist-in-Charge, USGS mhaney@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI dfee1@alaska.edu (907) 378-5460

(16) Next Notice:
2023-08-17 - Aniakchak, Aviation Color Code: GREEN (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20230817/1659Z)
(3) Volcano: Aniakchak (VNUM #312090)
(4) Current Color Code: GREEN
(5) Previous Color Code: YELLOW
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2023/A1278
(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 and the measurable uplift of the ground surface in the caldera have declined to background levels. Due to these changes, the Alaska Volcano Observatory is lowering the Aviation Color Code to GREEN and the Volcano Alert Level to NORMAL. There have been no signs of unrest in other monitoring data. 

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:

Matt Haney, Scientist-in-Charge, USGS mhaney@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.

2023-08-16 - Shishaldin, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20230816/1916Z)
(3) Volcano: Shishaldin (VNUM #311360)
(4) Current Color Code: ORANGE
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2023/A1272
(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 level of eruptive activity at Shishaldin Volcano has gradually declined since yesterday afternoon. Seismicity has decreased, and significant explosions or ash emissions are no longer detected. Clear web camera views this morning show only minor steaming at the summit. Recent satellite views indicated a persistent thermal anomaly at the summit, indicating the presence of hot eruptive material.

Based on previous eruption cycles, significant ash emissions may occur again and will likely be preceded by gradually increasing seismicity. Pyroclastic and mudflows will probably happen on the immediate flanks of the volcano should another vigorous episode of eruptive activity occur.

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network.  In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

 

(12) Volcanic cloud height: Minor, mostly steam emissions.
(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 10 miles (16 km). A 660 ft. (200 m) wide 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 26 confirmed eruptions since 1824. Most eruptions are relatively small, although the April-May 1999 event generated an ash column that reached 45,000 ft. (14 km) above sea level.

(15) Contacts:

Matt Haney, Scientist-in-Charge, USGS mhaney@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI dfee1@alaska.edu (907) 378-5460

(16) Next Notice:
2023-08-15 - Shishaldin, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20230815/2303Z)
(3) Volcano: Shishaldin (VNUM #311360)
(4) Current Color Code: ORANGE
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2023/A1271
(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:

Explosive eruptive activity is continuing at Shishaldin Volcano. A low-level ash cloud to about 16,000 ft (5 km) above sea level and moving northeast is evident in satellite data and was observed by passing pilots. The National Weather Service has issued a SIGMET for this ash cloud.

Based on previous eruption cycles, significant ash emissions may continue for several hours. Pyroclastic and mudflows are likely on the immediate flanks of the volcano.

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network. In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lightning data, and satellite images to detect eruptions.

 

(12) Volcanic cloud height: drifting below 16,000 ft (5 km) above sea level, see SIGMET. Emissions from the vent are likely occurring at low levels.
(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 10 miles (16 km). A 660 ft. (200 m) wide 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 26 confirmed eruptions since 1824. Most eruptions are relatively small, although the April-May 1999 event generated an ash column that reached 45,000 ft. (14 km) above sea level.

(15) Contacts:

Matt Haney, Scientist-in-Charge, USGS mhaney@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI dfee1@alaska.edu (907) 378-5460

(16) Next Notice:
2023-08-15 - Shishaldin, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20230815/1135Z)
(3) Volcano: Shishaldin (VNUM #311360)
(4) Current Color Code: ORANGE
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2023/A1266
(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:

Explosive eruptive activity is occurring at Shishaldin Volcano. A low-level ash cloud to about 25,000 ft (7.6 km) above sea level and moving northeast is evident in satellite data. This follows a several-hour increase in seismic tremor. Explosion signals have been detected in infrasound data since at least 2:00 AKDT (10:00 UTC) and the National Weather Service has detected lightning in the vicinity of the volcano. A SIGMET for this ash cloud has been issued.

Based on previous eruption cycles, significant ash emissions are likely to continue for the next few hours. Pyroclastic and mudflows are likely on the immediate flanks of the volcano.

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network.  In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

 

(12) Volcanic cloud height: drifting below 25,000 ft (7.6 km) above sea level, see SIGMET. Emissions from the vent are likely occurring at low levels.
(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 10 miles (16 km). A 660 ft. (200 m) wide 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 26 confirmed eruptions since 1824. Most eruptions are relatively small, although the April-May 1999 event generated an ash column that reached 45,000 ft. (14 km) above sea level.

(15) Contacts:

Matt Haney, Scientist-in-Charge, USGS mhaney@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI dfee1@alaska.edu (907) 378-5460

(16) Next Notice:
2023-08-15 - Shishaldin, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20230815/0227Z)
(3) Volcano: Shishaldin (VNUM #311360)
(4) Current Color Code: ORANGE
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2023/A1265
(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 level of unrest has increased at Shishaldin Volcano. A steady increase in seismic tremor has been observed over the past 5 hours. Elevated surface temperatures consistent with lava erupting at the summit are evident in the latest satellite data. Based on previous eruption cycles over the past month, ash emissions are likely to occur and may increase over the next few hours. 

Recent significant ash events during the current eruption resulted in ash clouds with heights up to 40,000 ft (12 km) above sea level.  These events can occur with little warning. It is also possible that ash emissions may occur at a lower-level, steady state and be sustained for many hours. AVO is monitoring the volcano closely and will issue additional Volcanic Activity Notice’s to provide notice of significant changes in activity as they occur.

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network. In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

 

 

(12) Volcanic cloud height: Unknown
(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 10 miles (16 km). A 660 ft. (200 m) wide 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 26 confirmed eruptions since 1824. Most eruptions are relatively small, although the April-May 1999 event generated an ash column that reached 45,000 ft. (14 km) above sea level.

(15) Contacts:

Matt Haney, Scientist-in-Charge, USGS mhaney@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI dfee1@alaska.edu (907) 378-5460

(16) Next Notice:
2023-08-05 - Shishaldin, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20230805/0355Z)
(3) Volcano: Shishaldin (VNUM #311360)
(4) Current Color Code: ORANGE
(5) Previous Color Code: RED
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2023/A1216
(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:

Volcanic activity has significantly declined at Shishaldin Volcano and any remaining ash emissions are likely low level. Seismic tremor began declining from a peak at 2:00 pm AKDT (22:00 UTC) and is and is currently at low levels. The eruption produced a sustained ash plume ash plume during the period of high seismicity which drifted to the northeast.  Currently, meteorological clouds at 30,000 ft (9 km) above sea level have obscured the volcano and any potential ash clouds.  It is possible that low level ash production could be continuing during this period of waning seismicity.  Due to this decrease in intensity of the eruption, the Aviation Color Code is being lowered to ORANGE and the Alert Level is being lowered to WATCH.

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network.  In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

 

 

(12) Volcanic cloud height: Unknown
(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 10 miles (16 km). A 660 ft. (200 m) wide 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 26 confirmed eruptions since 1824. Most eruptions are relatively small, although the April-May 1999 event generated an ash column that reached 45,000 ft. (14 km) above sea level.

(15) Contacts:

Matt Loewen, Acting Scientist-in-Charge, USGS, mloewen@usgs.gov, (907) 786-7497

Ronni Grapenthin, Acting Coordinating Scientist, UAFGI, rgrapenthin@alaska.edu, (907) 378-5460

(16) Next Notice:

Should volcanic activity change significantly, a new notice will be issued.

2023-08-04 - Shishaldin, Aviation Color Code: RED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20230804/2207Z)
(3) Volcano: Shishaldin (VNUM #311360)
(4) Current Color Code: RED
(5) Previous Color Code: RED
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2023/A1215
(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 continues at Shishaldin Volcano, with continuous ash emissions, strongly elevated surface temperatures, and high levels of seismic tremor. A continuous ash plume extends to the east-northeast with two branches visible in satellite imagery and confirmed by passing aircraft. The volcanic cloud extends up to ~112 miles (~180 km) from the volcano, with its top as high as 31,000 ft (9.4 km) above sea level. Additionally, a gas-rich but less ash-laden volcanic plume is also drifting to the southeast. The National Weather Service has issued a SIGMET for these ash clouds, a Marine Weather Statement and a Special Weather Statement for trace ash on marine waters and land areas downwind of Shishaldin Volcano. The color code and alert level remain at RED/WARNING. 

Based on previous eruption cycles, significant ash emissions are likely to continue for several hours. Pyroclastic and mudflows are likely on the immediate flanks of the volcano.

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network.  In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

 

 

 

(12) Volcanic cloud height: 31,000 ft. (9.4 km) above sea level
(13) Other volcanic cloud information: lower plume drifting NE, higher plume E
(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 10 miles (16 km). A 660 ft. (200 m) wide 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 26 confirmed eruptions since 1824. Most eruptions are relatively small, although the April-May 1999 event generated an ash column that reached 45,000 ft. (14 km) above sea level.

(15) Contacts:

Matt Loewen, Acting Scientist-in-Charge, USGS, mloewen@usgs.gov, (907) 786-7497

Ronni Grapenthin, Acting Coordinating Scientist, UAFGI, rgrapenthin@alaska.edu, (907) 378-5460

(16) Next Notice:

Should volcanic activity change significantly, a new notice will be issued.

2023-08-04 - Shishaldin, Aviation Color Code: RED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20230804/1817Z)
(3) Volcano: Shishaldin (VNUM #311360)
(4) Current Color Code: RED
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2023/A1214
(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:

An ash cloud from Shishaldin Volcano reaching 30,000 ft (9 km) above sea level was observed in satellite data at 9:00 am AKDT (17:00 UTC). This follows a several-hour increase in observed eruptive activity. In response, the Aviation Color Code is being raised to RED and the Volcano Alert Level is being raised to WARNING. The National Weather Service has issued a SIGMET for this ash cloud, and a Special Weather Statement has been issued for possible trace ash on marine waters downwind of Shishaldin Volcano.

Based on previous eruption cycles, significant ash emissions are likely to continue for several hours. Pyroclastic and mudflows are likely on the immediate flanks of the volcano.

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network.  In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

 

 

 

(12) Volcanic cloud height: 30,000 ft. (9 km) above sea level
(13) Other volcanic cloud information: lower plume driving NE, higher plume E
(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 10 miles (16 km). A 660 ft. (200 m) wide 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 26 confirmed eruptions since 1824. Most eruptions are relatively small, although the April-May 1999 event generated an ash column that reached 45,000 ft. (14 km) above sea level.

(15) Contacts:

Matt Loewen, Acting Scientist-in-Charge, USGS, mloewen@usgs.gov, (907) 786-7497

Ronni Grapenthin, Acting Coordinating Scientist, UAFGI, rgrapenthin@alaska.edu, (907) 378-5460

(16) Next Notice:
2023-08-04 - Shishaldin, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20230804/1704Z)
(3) Volcano: Shishaldin (VNUM #311360)
(4) Current Color Code: ORANGE
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2023/A1213
(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:

Explosive eruptive activity is occurring at Shishaldin Volcano. A low-level ash cloud up to 25,000 ft (7.6 km) above sea level and extending 37-47 miles (60-75 km) northeast of the volcano is evident in satellite data at 5:20 AM AKDT (13:20 UTC) and reported by passing pilots at 8:36 AM AKDT (16:36 UTC). This follows a 20-hour increase in seismic tremor and an increase in surface temperatures at the volcano seen in satellite data. Explosion signals have been detected in infrasound and seismic data overnight during cloudy altmospheric conditions. Surface temperatures have greatly increased in the past few hours. The National Weather Service has issued a SIGMET for this ash cloud.

Based on previous eruption cycles, significant ash emissions are likely to continue for the next few hours. Pyroclastic and mudflows are likely on the immediate flanks of the volcano.

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network.  In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

 

(12) Volcanic cloud height: 25,000 ft (7.6 km) above sea level
(13) Other volcanic cloud information: Extending up to 75 km northeast
(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 10 miles (16 km). A 660 ft. (200 m) wide 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 26 confirmed eruptions since 1824. Most eruptions are relatively small, although the April-May 1999 event generated an ash column that reached 45,000 ft. (14 km) above sea level.

(15) Contacts:

Matt Loewen, Acting Scientist-in-Charge, USGS, mloewen@usgs.gov, (907) 786-7497

Ronni Grapenthin, Acting Coordinating Scientist, UAFGI, rgrapenthin@alaska.edu, (907) 378-5460

(16) Next Notice:
2023-08-04 - Shishaldin, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20230804/0136Z)
(3) Volcano: Shishaldin (VNUM #311360)
(4) Current Color Code: ORANGE
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2023/A1205
(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 level of unrest has increased at Shishaldin Volcano. A steady increase in seismic tremor has been observed over the past 7 hours. Despite cloud cover obscuring the volcano, elevated surface temperatures consistent with lava erupting at the summit are evident in the latest satellite data. Based on previous eruption cycles, ash emissions are likely to occur and may increase over the next few hours. 

Recent significant ash events during the current eruption resulted in ash clouds with heights up to 40,000 ft (12 km) above sea level.  These events can occur with little warning. It is also possible that ash emissions may occur at a lower-level, steady state and be sustained for many hours. AVO is monitoring the volcano closely and will issue additional Volcanic Activity Notice’s to provide notice of significant changes in activity as they occur.

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network.  In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

 

 

(12) Volcanic cloud height: Unknown
(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 10 miles (16 km). A 660 ft. (200 m) wide 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 26 confirmed eruptions since 1824. Most eruptions are relatively small, although the April-May 1999 event generated an ash column that reached 45,000 ft. (14 km) above sea level.

(15) Contacts:

Matt Loewen, Acting Scientist-in-Charge, USGS, mloewen@usgs.gov, (907) 786-7497

Ronni Grapenthin, Acting Coordinating Scientist, UAFGI, rgrapenthin@alaska.edu, (907) 378-5460

(16) Next Notice:
2023-08-03 - Semisopochnoi, Aviation Color Code: GREEN (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20230803/2342Z)
(3) Volcano: Semisopochnoi (VNUM #311060)
(4) Current Color Code: GREEN
(5) Previous Color Code: YELLOW
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2023/A1198
(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 observed at Semisopochnoi volcano since May 5, 2023, and there are no signs of heighted volcanic unrest. Reflecting these conditions, the Aviation Color Code is being lowered to GREEN and Volcano Alert Level to NORMAL. 

The last evidence of ash emissions from the volcano was observed on May 5 and consisted of a light dusting of ash on the northwest flank of Mount Young. The last detection of possible explosions in monitoring data was April 25, 2023. Since this time, earthquake activity has been at low levels. Steam plumes continue from the north crater of Mount Young. Although steaming was not observed from this vent prior the start of this eruption, it is common for steam plumes to persist at volcanoes for years following an eruption as the volcano slowly cools. 

The current eruption sequence at Semisopochnoi began in September 2018 and has consisted of 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 with occasional periods of continuous ash production. While current observations indicate that this eruption may be over, it is also possible activity could resume, and small ash-producing events could occur with little warning. The Alaska Volcano Observatory will continue to closely monitor Semisopochnoi and report on any changes in activity. 

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: NA
(13) Other volcanic cloud information: none
(14) Remarks:

The remote Semisopochnoi volcano occupies a 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:

Matt Loewen, Acting Scientist-in-Charge, USGS, mloewen@usgs.gov, (907) 786-7497

Ronni Grapenthin, Acting Coordinating Scientist, UAFGI, rgrapenthin@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.

2023-07-26 - Shishaldin, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20230726/2127Z)
(3) Volcano: Shishaldin (VNUM #311360)
(4) Current Color Code: ORANGE
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2023/A1146
(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 eruption of Shishaldin Volcano has gradually declined after increasing overnight. Seismicity has decreased and significant explosions are no longer being detected in infrasound data. Meteorological clouds up to 20,000–25,000 ft (6.1–7.6 km) above sea level began obscuring views of the volcano starting around 11:30 am AKDT (17:30 UTC). It is likely that lingering low-level ash emissions are continuing in the vicinity of the volcano.

Seismic activity and satellite data indicated that eruptive activity began increasing around 10:00 pm AKDT on July 25 (July 26 06:00 UTC). A sustained 15,000 ft (6 km) ash cloud was detected around 5:00 am AKDT (13:00 UTC) and drifted ENE from the volcano. Ash emissions, while diffuse, were visible in satellite data extending about 78 mi (125 km) from the volcano until clouds obscured views starting around 11:30 AKDT (17:30 UTC). The National Weather Service issued a SIGMET for this cloud.

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network. The local monitoring network has been partially impaired over the last few weeks due to telecommunications issues but seismic stations and web cameras south of the volcano were brought back online on July 19. In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

 

(12) Volcanic cloud height: drifting below 15,000 ft (4.6 km) above sea level, see SIGMET. Emissions from the vent are likely occurring at low levels.
(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 10 miles (16 km). A 660 ft. (200 m) wide 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 26 confirmed eruptions since 1824. Most eruptions are relatively small, although the April-May 1999 event generated an ash column that reached 45,000 ft. (14 km) above sea level.

(15) Contacts:

Matt Loewen, Acting Scientist-in-Charge, USGS, cwaythomas@usgs.gov, (907) 786-7497

David Fee, Coordinating Scientist, UAFGI, dfee1@alaska.edu, (907) 378-5460

(16) Next Notice:
2023-07-26 - Shishaldin, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20230726/1151Z)
(3) Volcano: Shishaldin (VNUM #311360)
(4) Current Color Code: ORANGE
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2023/A1145
(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:

Explosive eruptive activity is occurring at Shishaldin Volcano. A low-level ash cloud to about 15,000 ft (6 km) above sea level and moving ENE is evident in satellite data. This follows a several-hour increase in seismic tremor and an increase in temperatures at the volcano seen in satellite data. Explosion signals have been detected in infrasound data since at least 02:00 AKDT (10 UTC). The National Weather Service has issued a SIGMET for this ash cloud, and a Marine Weather Statement has been issued for possible trace ash on marine waters NE of the volcano.

Based on previous eruption cycles, significant ash emissions are likely to continue for the next few hours. Pyroclastic and mudflows are likely on the immediate flanks of the volcano.

The last four significant ash events during the current eruption resulted in ash clouds with heights up to 40,000 ft. (12 km) above sea level, similar to other historical eruptions. These events can occur with little warning. 

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network. The local monitoring network has been partially impaired over the last few weeks due to telecommunications issues but seismic stations and web cameras south of the volcano were brought back online on July 19. In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

 

(12) Volcanic cloud height: 15,000 ft (4.6 km) above sea level
(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 10 miles (16 km). A 660 ft. (200 m) wide 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 26 confirmed eruptions since 1824. Most eruptions are relatively small, although the April-May 1999 event generated an ash column that reached 45,000 ft. (14 km) above sea level.

(15) Contacts:

Chris Waythomas, Acting Scientist-in-Charge, USGS, cwaythomas@usgs.gov, (907) 786-7497

David Fee, Coordinating Scientist, UAFGI, dfee1@alaska.edu, (907) 378-5460

(16) Next Notice:
2023-07-26 - Shishaldin, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20230726/1011Z)
(3) Volcano: Shishaldin (VNUM #311360)
(4) Current Color Code: ORANGE
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2023/A1144
(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 level of unrest has increased at Shishaldin Volcano. A steady increase in seismic tremor over the past 4 hours and an increase in temperatures at the volcano observed in satellite data over the past 2 hours suggests that explosive activity is imminent.  Despite cloud cover obscuring the volcano, elevated surface temperatures consistent with lava erupting at the summit are evident in the latest satellite data. Based on previous eruption cycles, minor ash emissions are likely to occur and may increase over the next few hours. 

The last four significant ash events during the current eruption resulted in ash clouds with heights up to 40,000 ft. (12 km) above sea level, similar to other historical eruptions. These events can occur with little warning. 

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network. The local monitoring network has been partially impaired over the last few weeks due to telecommunications issues but seismic stations and web cameras south of the volcano were brought back online on July 19. In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

 

(12) Volcanic cloud height: Unknown but explosive eruption is imminent.
(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 10 miles (16 km). A 660 ft. (200 m) wide 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 26 confirmed eruptions since 1824. Most eruptions are relatively small, although the April-May 1999 event generated an ash column that reached 45,000 ft. (14 km) above sea level.

(15) Contacts:

Chris Waythomas, Acting Scientist-in-Charge, USGS, cwaythomas@usgs.gov, (907) 786-7497

David Fee, Coordinating Scientist, UAFGI, dfee1@alaska.edu, (907) 378-5460

(16) Next Notice:
2023-07-23 - Shishaldin, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20230723/1218Z)
(3) Volcano: Shishaldin (VNUM #311360)
(4) Current Color Code: ORANGE
(5) Previous Color Code: RED
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2023/A1123
(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:

Volcanic activity has significantly declined at Shishaldin Volcano. Seismic tremor began declining from a peak at 12:30 am AKDT (08:30 UTC) and is and is currently at low levels. Significant ash eruption notably decreased in satellite data around 1:30 am (09:30 UTC). Satellite data continue to indicate elevated surface temperatures at the summit associated with lava erupting at the surface and possible low-level ash emissions below regional cloud tops which are currently at around 20,000 ft. (6 km) above sea level.

A sustained ash plume with a height of 37,000 ft. (11 km) above sea level erupted between 11:20 pm AKDT on July 22 (07:20 UTC on July 23) and 12:30 am on July 23 (08:30 UTC on July 23). Around this time plume height decreased to around 15,000 ft. (4.5 km) above sea level.

A detached plume is currently drifting to the northeast along the Alaska Peninsula. The National Weather Service has issued a SIGMET for this ash cloud, as well as a Marine Weather Statement and an Ashfall Advisory that were issued for areas that might expect ashfall associated with this eruption.

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network. The local monitoring network has been partially impaired over the last few weeks due to telecommunications issues but seismic stations and web cameras south of the volcano were brought back online on July 19. In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

 

(12) Volcanic cloud height: unknown, below 20,000 ft. (6 km) above sea level
(13) Other volcanic cloud information: Main eruption cloud detached and drifting to the northeast, see current NWS SIGMET.
(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 10 miles (16 km). A 660 ft. (200 m) wide 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 26 confirmed eruptions since 1824. Most eruptions are relatively small, although the April-May 1999 event generated an ash column that reached 45,000 ft. (14 km) above sea level.

(15) Contacts:

Chris Waythomas, Acting Scientist-in-Charge, USGS, cwaythomas@usgs.gov, (907) 786-7497

David Fee, Coordinating Scientist, UAFGI, dfee1@alaska.edu, (907) 378-5460

(16) Next Notice:
2023-07-23 - Shishaldin, Aviation Color Code: RED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20230723/0743Z)
(3) Volcano: Shishaldin (VNUM #311360)
(4) Current Color Code: RED
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2023/A1122
(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:

An ash cloud from Shishaldin Volcano reaching 30,000 ft. (9 km) was observed in satellite data and pilot reports at 11:30 pm AKDT (07:30 UTC on July 23). This follows a several-hour increase in observed eruptive activity. In response, the aviation Color Code is being raised to RED and the Volcano Alert Level is being raised to WARNING. The National Weather Service has issued a SIGMET for this ash cloud, and a Special Weather Statement has been issued for possible trace ash on False Pass.

Based on previous eruption cycles, significant ash emissions are likely to continue for an hour or more. Pyroclastic and mudflows are likely on the immediate flanks of the volcano.

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network. The local monitoring network has been partially impaired over the last few weeks due to telecommunications issues but seismic stations and web cameras south of the volcano were brought back online on July 19. In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

(12) Volcanic cloud height: 30,000 ft. (9 km) above sea level
(13) Other volcanic cloud information: Plume is moving northeast
(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 10 miles (16 km). A 660 ft. (200 m) wide 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 26 confirmed eruptions since 1824. Most eruptions are relatively small, although the April-May 1999 event generated an ash column that reached 45,000 ft. (14 km) above sea level.

(15) Contacts:

Chris Waythomas, Acting Scientist-in-Charge, USGS, cwaythomas@usgs.gov, (907) 786-7497

David Fee, Coordinating Scientist, UAFGI, dfee1@alaska.edu, (907) 378-5460

(16) Next Notice:
2023-07-23 - Shishaldin, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20230723/0053Z)
(3) Volcano: Shishaldin (VNUM #311360)
(4) Current Color Code: ORANGE
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2023/A1121
(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 level of unrest has increased at Shishaldin Volcano over the past 6 hours. A steady increase in seismic tremor and intermittent infrasound signals consistent with small explosions are ongoing. Despite cloud cover obscuring the volcano, elevated surface temperatures consistent with lava erupting at the summit are evident in the latest satellite data. Based on previous eruption cycles, minor ash emissions are likely to occur and may increase over the next few hours. Clouds are obscuring web cameras and satellite images, and we have had no clear views of the volcano over the past day. Based on the level of unrest, we infer that any ash emissions occurring are below 20,000 ft. (6 km) above sea level and below the altitude of clouds in the region.

The last three significant ash events during the current eruption resulted in ash clouds up to 40,000 ft. (12 km) above sea level, similar to other historical eruptions. These events can occur with little warning. 

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network. The local monitoring network has been partially impaired over the last few weeks due to telecommunications issues but seismic stations and web cameras south of the volcano were brought back online on July 19. In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

(12) Volcanic cloud height: unknown
(13) Other volcanic cloud information: Meteorological cloud tops 20,000–30,000 ft. (6–9 km) above sea level. Ash emissions possible below this level.
(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 10 miles (16 km). A 660 ft. (200 m) wide 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 26 confirmed eruptions since 1824. Most eruptions are relatively small, although the April-May 1999 event generated an ash column that reached 45,000 ft. (14 km) above sea level.

(15) Contacts:

Chris Waythomas, Acting Scientist-in-Charge, USGS, cwaythomas@usgs.gov, (907) 786-7497

David Fee, Coordinating Scientist, UAFGI, dfee1@alaska.edu, (907) 378-5460

(16) Next Notice:
2023-07-19 - Cleveland, Aviation Color Code: YELLOW (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20230719/2018Z)
(3) Volcano: Cleveland (VNUM #311240)
(4) Current Color Code: YELLOW
(5) Previous Color Code: UNASSIGNED
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2023/A1094
(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 an increase in the number of earthquakes observed near Cleveland volcano over the past week. Numerous earthquakes have been detected and 37 of these were large enough to be located by the local seismic network. Most of the earthquakes from early in the week located in the mid to shallow portions of the Earth’s crust, less than 11 miles (18 km) below the surface, while more recent earthquakes have been located at shallower depths, less than 4 miles (6 km) below the surface. These earthquakes are small (less than magnitude 2), but the frequency of events is unusual for Cleveland. These data along with satellite observations of elevated surface temperatures at the summit crater and continued gas emissions suggest an increased likelihood of a future eruption. In response, the Alaska Volcano Observatory is increasing the Aviation Color Code to YELLOW and the Volcano Alert Level to ADVISORY.

The last eruptive activity at Cleveland volcano was a short-lived explosion during 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 have occurred without warning and typically generate small clouds of volcanic ash that are a hazard in the immediate vicinity of the volcano, though more significant ash emissions are possible.

Cleveland volcano is currently monitored with a five-station real-time seismic network. Based on past events, explosive eruptions of Cleveland may occur with little or no warning. 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:

Kristi Wallace, Acting Scientist-in-Charge, USGS kwallace@usgs.gov (907) 786-7497

Pavel Izbekov, Acting Coordinating Scientist, UAFGI peizbekov@alaska.edu (907) 378-5460

(16) Next Notice:
2023-07-19 - Takawangha, Aviation Color Code: GREEN (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20230719/0028Z)
(3) Volcano: Takawangha (VNUM #311090)
(4) Current Color Code: GREEN
(5) Previous Color Code: YELLOW
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2023/A1093
(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 when over 150 earthquakes per day were located on Tanaga Island to less than 3 earthquakes per day in the last few weeks. Recent satellite images do not indicate any ongoing deformation on the island. No other signs of volcanic unrest have been detected. The Alaska Volcano Observatory is therefore lowering the Aviation Color Code to GREEN and the Volcano Alert Level to NORMAL.

The Alaska Volcano Observatory will continue to closely monitor seismic activity on Tanaga Island.

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:

Kristi Wallace, Acting Scientist-in-Charge, USGS kwallace@usgs.gov (907) 786-7497

Pavel Izbekov, Acting Coordinating Scientist, UAFGI peizbekov@alaska.edu (907) 378-5460

(16) Next Notice:
2023-07-19 - Tanaga, Aviation Color Code: GREEN (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20230719/0028Z)
(3) Volcano: Tanaga (VNUM #311080)
(4) Current Color Code: GREEN
(5) Previous Color Code: YELLOW
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2023/A1092
(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 when over 150 earthquakes per day were located on Tanaga Island to less than 3 earthquakes per day in the last few weeks. Recent satellite images do not indicate any ongoing deformation on the island. No other signs of volcanic unrest have been detected. The Alaska Volcano Observatory is therefore lowering the Aviation Color Code to GREEN and the Volcano Alert Level to NORMAL.

The Alaska Volcano Observatory will continue to closely monitor seismic activity on Tanaga Island.

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:

Kristi Wallace, Acting Scientist-in-Charge, USGS kwallace@usgs.gov (907) 786-7497

Pavel Izbekov, Acting Coordinating Scientist, UAFGI peizbekov@alaska.edu (907) 378-5460

(16) Next Notice:
2023-07-18 - Shishaldin, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20230718/2008Z)
(3) Volcano: Shishaldin (VNUM #311360)
(4) Current Color Code: ORANGE
(5) Previous Color Code: RED
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2023/A1084
(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 eruption of Shishaldin Volcano has gradually declined. Current observations indicate continued but low-level ash emissions below 10,000 ft. (3 km) above sea level and drifting to the south. Reflecting this lower-level activity, the Aviation Color Code is being reduced to ORANGE and the Volcano Alert Level is being lowered to WATCH. 

This morning a significant ash plume was detected starting around 7:00 am AKDT (15:00 UTC) and reaching a height of around 30,000 ft. (7 km) above sea level. Around 9:30 am AKDT (17:30 UTC) satellite data showed the main initial plume had detached but residual, low-level ash emissions continued from the vent. The detached plume is still visible between 60–280 mi (100 and 450 km) away from the volcano. The National Weather Service has issued a SIGMET for this cloud.

Explosive eruptive activity can resume quickly and with little warning. Eruptions from Shishaldin have produced minor and on occasion significant ash clouds in the past. Shishaldin is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network. The local monitoring network is partially impaired, therefore AVO is also using nearby geophysical networks, satellite data and regional infrasound and lighting data to detect activity. AVO will continue to closely monitor unrest at Shishaldin Volcano.

 

(12) Volcanic cloud height: 10,000 ft. above sea level
(13) Other volcanic cloud information: Low level ash cloud drifting south from the summit. Main eruption cloud detached 60–280 mi (100 and 450 km) to the south, see current NWS SIGMET.
(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 26 confirmed eruptions since 1824. 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

Pavel Izbekov, Acting Coordinating Scientist, UAFGI peizbekov@alaska.edu (907) 378-5460

(16) Next Notice:
2023-07-18 - Shishaldin, Aviation Color Code: RED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20230718/1637Z)
(3) Volcano: Shishaldin (VNUM #311360)
(4) Current Color Code: RED
(5) Previous Color Code: RED
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2023/A1083
(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:

An ash cloud with an initial height of around 30,000 ft. (7 km) above sea level from Shishaldin volcano began at 7:00 am AKDT (15:00 UTC) and is drifting SSE. The eruption is continuing and recent pilot observations estimated a 24,000 ft. (6 km) above sea level height. The aviation Color Code remains at RED and the Volcano Alert Level at WARNING. The National Weather Service has issued a SIGMET for this activity.

Eruptive activity began increasing overnight starting around 1 am AKDT (09:00 UTC) with increased lava eruption from or within the summit crater but no significant ash emissions. Activity was detected on regional infrasound arrays, increasing seismic tremor, and elevated surface temperatures in satellite data. Overnight webcam images confirmed glowing from the summit with only minor ash emission.

Eruptions from Shishaldin have produced minor and on occasion significant ash clouds in the past.  These can occur with little warning. Shishaldin is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network. The local monitoring network is partially impaired, therefore AVO is also using nearby geophysical networks, satellite data and regional infrasound and lighting data to detect activity. AVO will continue to closely monitor unrest at Shishaldin Volcano. 

 

(12) Volcanic cloud height: 30,000 ft. above sea level
(13) Other volcanic cloud information: SSE Drifting ash cloud seen in satellite imagery, see current NWS SIGMET
(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 26 confirmed eruptions since 1824. 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

Pavel Izbekov, Acting Coordinating Scientist, UAFGI peizbekov@alaska.edu (907) 378-5460

(16) Next Notice:
2023-07-18 - Shishaldin, Aviation Color Code: RED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20230718/1556Z)
(3) Volcano: Shishaldin (VNUM #311360)
(4) Current Color Code: RED
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2023/A1082
(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 eruption of Shishaldin Volcano has intensified. A rapidly growing ash cloud was observed starting at 7:00 am AKDT (15:00 UTC) and drifting SSE. Cloud height is undertermined at this time and could be more than 20,000 ft. above sea level (6 km). In response, the aviation Color Code is being raised to RED and the Volcano Alert Level is being raised to WARNING. The National Weather Service has issued a SIGMET for this activity.

Eruptive activity began increasing overnight starting around 1 am AKDT (09:00 UTC) with increased lava eruption from or within the summit crater but no significant ash emissions. Activity was detected on regional infrasound arrays, increasing seismic tremor, and elevated surface temperatures in satellite data. Overnight webcam images confirmed glowing from the summit with only minor ash emission.

Eruptions from Shishaldin have produced minor and on occasion significant ash clouds in the past.  These can occur with little warning. Shishaldin is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network. The local monitoring network is partially impaired, therefore AVO is also using nearby geophysical networks, satellite data and regional infrasound and lighting data to detect activity. AVO will continue to closely monitor unrest at Shishaldin Volcano. 

 

(12) Volcanic cloud height: unknown at this time, appear to have rapid growth over 20,000 ft. asl
(13) Other volcanic cloud information: SSE Drifting ash cloud seen in satellite imagery, see current NWS SIGMET
(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 26 confirmed eruptions since 1824. 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

Pavel Izbekov, Acting Coordinating Scientist, UAFGI peizbekov@alaska.edu (907) 378-5460

(16) Next Notice:
2023-07-18 - Ahyi Seamount, Aviation Color Code: UNASSIGNED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20230718/0102Z)
(3) Volcano: Ahyi Seamount (VNUM #284141)
(4) Current Color Code: UNASSIGNED
(5) Previous Color Code: YELLOW
(6) Source: U.S. Geological Survey
(7) Notice Number: 2023/N168
(8) Volcano Location: N 20 deg 25 min E 145 deg 1 min
(9) Area: Northern Mariana Islands
(10) Summit Elevation: -259 ft (-79 m)
(11) Volcanic Activity Summary:

Consistent signs of unrest at Ahyi Seamount have not occurred for over four weeks. Underwater pressure sensors near Wake Island have not detected clear signs of underwater volcanic activity since early June and the last satellite observations of discolored water near the seamount was seen on May 22, 2023. 

Starting mid-October 2022, hydroacoustic sensors at Wake Island, 1,410 miles (2,270 km) east of Ahyi, began recording signals consistent with activity from an undersea volcanic source. In collaboration with the Laboratoire de Geophysique in Tahiti, a combined analysis of the hydroacoustic signals and data from seismic stations located at Guam and Chichijima Island, Japan, confirmed that the source of this activity was at or near Ahyi seamount.  Observations of discolored water above the seamount in satellite data confirmed activity at Ahyi. The activity appears to have paused beginning in early April but briefly resumed in late May.  

Due to the apparent absence of activity over the last month, the aviation color code is being lowered from YELLOW to UNASSIGNED and the alert level is being lowered from ADVISORY to UNASSIGNED. 

 

(12) Volcanic cloud height: No volcanic cloud produced
(13) Other volcanic cloud information: Water discoloration no longer observed above seamount in satellite images
(14) Remarks:

Ahyi seamount is a large conical submarine volcano that rises to within 450 ft (137 m) of the sea surface about 11 miles (18 km) southeast of Farallon de Pajaros (Uracas) Island in the northern Marianas, about 370 miles (600 km) 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 (+/- 9 miles or 15 km) at a location near the southern base of Ahyi.
 

(15) Contacts:

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

(16) Next Notice:

A new VAN will be issued if conditions change significantly or alert levels are modified.

2023-07-16 - Shishaldin, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20230716/1534Z)
(3) Volcano: Shishaldin (VNUM #311360)
(4) Current Color Code: ORANGE
(5) Previous Color Code: RED
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2023/A1067
(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:

Explosive eruptive activity at Shishaldin Volcano has declined. Seismicity has significantly declined and no explosion signals are being detected in infrasound (pressure sensor) data. The drifting ash cloud from last night's activity is still visible in satellite imagery about 350 nautical miles ESE from the volcano. The NWS has a SIGMET for this cloud and estimate it to be under 16,000 ft (4.9 km) above sea level. In response to this decline in explosive activity, the Aviation Color Code is being reduced to ORANGE and the Volcano Alert Level is being raised to WATCH. 

Explosive eruptive activity can resume quickly and with little warning. Eruptions from Shishaldin have produced minor and on occasion significant ash clouds in the past. Shishaldin is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network. The local monitoring network is partially impaired, therefore AVO is also using nearby geophysical networks, satellite data and regional infrasound and lighting data to detect activity. AVO will continue to closely monitor unrest at Shishaldin Volcano. 

 

(12) Volcanic cloud height: none detected at the volcano, drifting ash cloud under 16,000 ft above sea level
(13) Other volcanic cloud information: ESE Drifting ash cloud still seen in satellite imagery, see current NWS SIGMET
(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 26 confirmed eruptions since 1824. 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

Pavel Izbekov, Acting Coordinating Scientist, UAFGI peizbekov@alaska.edu (907) 378-5460

(16) Next Notice:
2023-07-16 - Shishaldin, Aviation Color Code: RED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20230716/0757Z)
(3) Volcano: Shishaldin (VNUM #311360)
(4) Current Color Code: RED
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2023/A1066
(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 explosive eruption of Shishaldin Volcano is continuing. A continuous ash plume now extends over 80 mi (125 km) to the SSE from the volcano with an altitude of about 16,000 ft (4.9 km) above sea level. Seismicity has remained elevated for over 6 hours and frequent explosion signals are being detected at regional infrasound (pressure sensor) networks. Some explosions are sending ash plumes as high as 20,000 ft (6 km) above sea level. Due to the duration of this current activity and the extent of the distributing ash cloud the Aviation Color Code is being raised to RED and the Volcano Alert Level is being raised to WARNING. 

The recent magnitude 7.3 earthquake located 55 mi (89 km) SW of Sand Point is not related to volcanic activity.

Eruptions from Shishaldin have produced minor and on occasion significant ash clouds in the past. These can occur with little warning. Shishaldin is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network. The local monitoring network is partially impaired, therefore AVO is also using nearby geophysical networks, satellite data and regional infrasound and lighting data to detect activity. AVO will continue to closely monitor unrest at Shishaldin Volcano. 

 

(12) Volcanic cloud height: up to 20,000 feet above sea level
(13) Other volcanic cloud information: Drifting more than 80 mi (125 km) to the SSE
(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 26 confirmed eruptions since 1824. 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

Pavel Izbekov, Acting Coordinating Scientist, UAFGI peizbekov@alaska.edu (907) 378-5460

(16) Next Notice:
2023-07-16 - Shishaldin, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20230716/0552Z)
(3) Volcano: Shishaldin (VNUM #311360)
(4) Current Color Code: ORANGE
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2023/A1065
(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 eruption of Shishaldin Volcano has intensified. An ash cloud to 15,000 ft  (4.6 km) above sea level and drifting to the SSE has been observed in satellite data starting at about 9:00 pm AKDT (17:00 UTC). The National Weather Service has issued a SIGMET for this activty.  Seismic tremor amplitudes began to increase starting around 5:00 pm AKDT (1:00 UTC) and are continuing.  The actvity has also been observed on regional infrasound (presure sensor) arrays. 

Eruptions from Shishaldin have produced minor and on occasion significant ash clouds in the past.  These can occur with little warning. Shishaldin is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network. The local monitoring network is partially impaired, therefore AVO is also using nearby geophysical networks, satellite data and regional infrasound and lighting data to detect activity. AVO will continue to closely monitor unrest at Shishaldin Volcano. 

 

(12) Volcanic cloud height: 15,000 feet above sea level
(13) Other volcanic cloud information: Drifting to the SSE
(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 26 confirmed eruptions since 1824. 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

Pavel Izbekov, Acting Coordinating Scientist, UAFGI peizbekov@alaska.edu (907) 378-5460

(16) Next Notice:
2023-07-14 - Shishaldin, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20230714/1934Z)
(3) Volcano: Shishaldin (VNUM #311360)
(4) Current Color Code: ORANGE
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2023/A1050
(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 significant explosion occurred at 1:09 am AKDT (9:09 UTC) this morning and produced an ash cloud that initially reached 30,000 to 40,000 ft (9–12 km) above sea level and drifted south over the Pacific Ocean. A second smaller explosion occurred at 7:10 am AKDT (15:10 UTC) and reached ~15,000 ft (4.5 km) above sea level. The National Weather Service issued a SIGMET for these events and suggested a maximum cloud height of 25,000 ft (7.6 km) above sea level for the drifting ash cloud. Web camera images and pilot reports show continued low-level ash emissions this morning including a small ash cloud near the summit around 10:30 am AKDT (18:30 UTC).  

Eruptions from Shishaldin have produced minor and on occasion significant ash clouds in the past.  These can occur with little warning. Shishaldin is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network. The local monitoring network is partially impaired, therefore AVO is also using nearby geophysical networks, satellite data and regional infrasound and lighting data to detect activity. AVO will continue to closely monitor unrest at Shishaldin Volcano. 

 

(12) Volcanic cloud height: 15,000 feet above sea level
(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 26 confirmed eruptions since 1824. 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

Pavel Izbekov, Acting Coordinating Scientist, UAFGI peizbekov@alaska.edu (907) 378-5460

(16) Next Notice:
2023-07-12 - Shishaldin, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20230712/2013Z)
(3) Volcano: Shishaldin (VNUM #311360)
(4) Current Color Code: ORANGE
(5) Previous Color Code: YELLOW
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2023/A1035
(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:

Strongly elevated surface temperatures continue to be observed at the summit of Shishaldin Volcano in satellite data. Incandescence at the summit was observed in web camera images from last night and sulfur dioxide was detected in satellite data over the past day. In addition, seismic tremor amplitudes have increased over the past day. Together, these observations suggest that lava is likely present within the summit crater of Shishaldin. In response, the Alaska Volcano Observatory is raising the Aviation Color Code to ORANGE and the Alert Level to WATCH.  

Shishaldin is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network. The local monitoring network is partially impaired, therefore AVO is also using nearby geophysical networks, satellite data and regional infrasound and lighting data to detect activity. AVO will continue to closely monitor unrest at Shishaldin Volcano. 

 

(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 26 confirmed eruptions since 1824. 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

David Fee, Coordinating Scientist, UAFGI dfee1@alaska.edu (907) 378-5460

(16) Next Notice:
2023-07-11 - Shishaldin, Aviation Color Code: YELLOW (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20230711/2239Z)
(3) Volcano: Shishaldin (VNUM #311360)
(4) Current Color Code: YELLOW
(5) Previous Color Code: GREEN
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2023/A1034
(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:

Strongly elevated surface temperatures at the summit of Shishaldin Volcano have been observed in satellite data over the past day. Intermittent tremor and low-frequency earthquakes over the past week have gradually become more regular and consistent in the past day. In response, the Alaska Volcano Observatory is raising the Aviation Color Code to YELLOW and the Alert Level to ADVISORY. 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, web cameras, and a telemetered geodetic network. The local monitoring network is partially impaired, therefore AVO is also using nearby geophysical networks, satellite data and regional infrasound and lighting data to detect activity. AVO will continue to closely monitor unrest at Shishaldin Volcano.
 

(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 26 confirmed eruptions since 1824. 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

David Fee, Coordinating Scientist, UAFGI dfee1@alaska.edu (907) 378-5460

(16) Next Notice:
2023-06-30 - Kilauea, Aviation Color Code: YELLOW (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20230630/1835Z)
(3) Volcano: Kilauea (VNUM #332010)
(4) Current Color Code: YELLOW
(5) Previous Color Code: ORANGE
(6) Source: Hawaiian Volcano Observatory
(7) Notice Number: 2023/H245
(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 June 19 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.  

Seismic activity—including eruptive tremor—in the summit region has been low since the eruption ceased. Over that period, gradual inflation has been recorded at summit tiltmeters. Overnight webcam views showed some incandescence from previously erupted lava as the lava proceeds to cool. There remains the potential for eruptive activity to resume in the near future at or near the summit of Kīlauea with little or no warning.

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

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:

askHVO@usgs.gov

(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:

2023-06-08 - Kilauea, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20230608/1837Z)
(3) Volcano: Kilauea (VNUM #332010)
(4) Current Color Code: ORANGE
(5) Previous Color Code: RED
(6) Source: Hawaiian Volcano Observatory
(7) Notice Number: 2023/H221
(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:

 

HVO is lowering Kīlauea’s volcano alert level from WARNING to WATCH because the initial high effusion rates have declined, and no infrastructure is threatened.  Associated hazards are confined to the closed area established by Hawaiʻi Volcanoes National Park.

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. The eruption plume continues to rise to the base of the inversion level at about 8,000-10,000 feet above sea level as it did yesterday.  The plume is largely composed of sulfur dioxide gas and minor volcanic particles, but in lower concentrations due to the drop in effusion rate.  Hazards associated with the eruption are limited and are described below. 

Kīlauea’s summit eruption is expected to continue and remain 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 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/. 

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 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. 

(15) Contacts:

askHVO@usgs.gov

(16) Next Notice:

Kīlauea updates will continue to 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:

2023-06-07 - Kilauea, Aviation Color Code: RED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20230607/1447Z)
(3) Volcano: Kilauea (VNUM #332010)
(4) Current Color Code: RED
(5) Previous Color Code: ORANGE
(6) Source: Hawaiian Volcano Observatory
(7) Notice Number: 2023/H159
(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 4:44 a.m. HST on June 7, 2023, the USGS Hawaiian Volcano Observatory 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.

The USGS Hawaiian Volcano Observatory is elevating Kīlauea’s volcano alert level from WATCH to WARNING and its aviation color code from ORANGE to RED as this eruption and associated hazards are evaluated.  

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.

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

 

 

(12) Volcanic cloud height: Unknown
(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/. 

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 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. 

(15) Contacts:

askHVO@usgs.gov

(16) Next Notice:

Kīlauea updates will continue to 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:

2023-06-07 - Kilauea, Aviation Color Code: ORANGE (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20230607/1314Z)
(3) Volcano: Kilauea (VNUM #332010)
(4) Current Color Code: ORANGE
(5) Previous Color Code: YELLOW
(6) Source: Hawaiian Volcano Observatory
(7) Notice Number: 2023/H146
(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 the evening of June 6, 2023, indicating movement of magma in the subsurface.

The USGS Hawaiian Volcano Observatory is raising the volcano alert level/aviation color code for Kīlauea from ADVISORY/YELLOW to WATCH/ORANGE due to this activity.

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. Based on patterns of earthquake activity and ground deformation, it is likely that any new eruptive activity will occur in Halemaʻumaʻu crater, within the closed area of Hawaiʻi Volcanoes National Park. 

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.

 

 

(12) Volcanic cloud height: N/A
(13) Other volcanic cloud information: N/A
(14) Remarks:

Please see the Hawaiʻi Volcanoes National Park website for visitor information: https://www.nps.gov/havo/index.htm. 

Hazard Analysis: 

Kīlauea summit eruptive activity over the past several years has occurred at the base of Halemaʻumaʻu crater, within the closed area of Hawaiʻi Volcanoes National Park. During Kīlauea summit eruptions, the high level of volcanic gas—primarily water vapor (H2O), carbon dioxide (CO2), and sulfur dioxide (SO2)—being emitted is the primary hazard of concern, as this hazard can have far-reaching effects downwind. Passive volcanic degassing can occur from within Halemaʻumaʻu crater even during periods of no eruptive activity. As SO2 is released from the summit, it reacts in the atmosphere to create the visible haze known as vog (volcanic smog) that has been observed downwind of Kīlauea. Vog creates the potential for airborne health hazards to residents and visitors, damages agricultural crops and other plants, and affects livestock. For more information on gas hazards at the summit of Kīlauea, please see: https://pubs.er.usgs.gov/publication/fs20173017. Vog information can be found at https://vog.ivhhn.org.  

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


 

(15) Contacts:

askHVO@usgs.gov

(16) Next Notice:

Kīlauea updates will continue to 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:

2023-06-06 - Iliamna, Aviation Color Code: GREEN (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20230606/0343Z)
(3) Volcano: Iliamna (VNUM #313020)
(4) Current Color Code: GREEN
(5) Previous Color Code: YELLOW
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2023/A816
(8) Volcano Location: N 60 deg 1 min W 153 deg 5 min
(9) Area: Cook Inlet-South Central
(10) Summit Elevation: 10016 ft (3053 m)
(11) Volcanic Activity Summary:

Previously reported earthquake activity culminated in an ice-rock avalanche slightly before 5:14 pm AKDT this evening (1:14 June 6, 2023 UTC). Although we lack visual confirmation at this time, the seismic signals recorded match historic observations of avalanches associated with Red Glacier on Iliamna Volcano’s eastern flank. Seismicity has since declined to background levels. The Aviation Color Code and Volcano Alert Level is therefore being lowered to GREEN and NORMAL.

(12) Volcanic cloud height: NA
(13) Other volcanic cloud information: Unknown
(14) Remarks:

Iliamna Volcano is located on the western side of lower Cook Inlet in the Lake Clark National Park. Iliamna is a snow-covered stratovolcano which rises 10,020 feet above sea level. Although steam plumes occur on its eastern flanks, there has been no historic volcanic activity at Iliamna. Iliamna is located 225 km (140 miles) southwest of Anchorage and 113 km (70 miles) southwest of Homer.

(15) Contacts:

Aaron Wech, Acting Scientist-in-Charge, USGS awech@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

2023-06-06 - Iliamna, Aviation Color Code: YELLOW (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20230606/0053Z)
(3) Volcano: Iliamna (VNUM #313020)
(4) Current Color Code: YELLOW
(5) Previous Color Code: GREEN
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2023/A815
(8) Volcano Location: N 60 deg 1 min W 153 deg 5 min
(9) Area: Cook Inlet-South Central
(10) Summit Elevation: 10016 ft (3053 m)
(11) Volcanic Activity Summary:

An increase in seismicity has been observed at Iliamna volcano beginning at about 12:00 pm AKDT June 5, 2023 (20:00 UTC). The rate of earthquakes initially occurred in 1 minute intervals and have been becoming more closely spaced. There is a possibility that the earthquakes may be related to magmatic movement or hydrothermal fluids beneath the volcano. However, similar activity has been observed before large mass movements or avalanches at Iliamna volcano, and AVO cannot rule out either possibility at this time.

Due to the seismicity at Iliamna being above background levels the Aviation Color Code and Volcano Alert level for Iliamna are being raised to YELLOW and ADVISORY.

(12) Volcanic cloud height: NA
(13) Other volcanic cloud information: Unknown
(14) Remarks:

Iliamna volcano is located on the western side of lower Cook Inlet in the Lake Clark National Park. Iliamna is a snow-covered stratovolcano which rises 10,020 feet above sea level. Although steam plumes occur on its eastern flanks, there has been no historic volcanic activity at Iliamna. Iliamna is located 225 km (140 miles) southwest of Anchorage and 113 km (70 miles) southwest of Homer.

(15) Contacts:

Aaron Wech, Acting Scientist-in-Charge, USGS awech@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

2023-05-22 - Ahyi Seamount, Aviation Color Code: YELLOW (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20230522/2039Z)
(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: 2023/N124
(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:

Signals consistent with eruptive activity at Ahyi seamount began to be observed in underwater pressure sensors at Wake Island beginning on May 21, 2023, at about 10:10 PM ChST (12:10 PM UTC) and are continuing. A plume of discolored sea water was observed above the area of the previously active vent in a satellite image on May 22, 2023, at 10:43 AM ChST (00:43 UTC). Due to this renewed activity at Ahyi Seamount The Aviation Color Code and Volcano Alert Level are being raised to YELLOW/ADVISORY. 

Starting mid-October 2022, hydroacoustic sensors at Wake Island, 1,410 miles (2,270 km) east of Ahyi, began recording signals consistent with activity from an undersea volcanic source. In collaboration with the Laboratoire de Geophysique in Tahiti, a combined analysis of the hydroacoustic signals and data from seismic stations located at Guam and Chichijima Island, Japan, confirmed that the source of this activity was at or near Ahyi seamount.  Observations of discolored water above the seamount in satellite data confirmed activity at Ahyi. The activity appears to have paused beginning in early April but has now resumed.  

 

(12) Volcanic cloud height: No volcanic cloud produced
(13) Other volcanic cloud information: Unknown
(14) Remarks:

Ahyi seamount is a large conical submarine volcano that rises to within 450 ft (137 m) of the sea surface about 11 miles (18 km) southeast of Farallon de Pajaros (Uracas) Island in the northern Marianas, about 370 miles (600 km) 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 (+/- 9 miles or 15 km) at a location near the southern base of Ahyi.
 

(15) Contacts:

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

(16) Next Notice:

A new VAN will be issued if conditions change significantly or alert levels are modified.

2023-05-17 - Semisopochnoi, Aviation Color Code: YELLOW (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20230517/2125Z)
(3) Volcano: Semisopochnoi (VNUM #311060)
(4) Current Color Code: YELLOW
(5) Previous Color Code: ORANGE
(6) Source: Alaska Volcano Observatory
(7) Notice Number: 2023/A694
(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:

The level of eruptive activity at Semisopochnoi has declined in the past week. The last evidence of ash emissions from the volcano was observed on May 5 and consisted of a light dusting of ash on the northwest flank of Mount Young. The Aviation Color Code and Volcano Alert Level are being lowered to YELLOW/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 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: NA
(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 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.

2023-04-25 - Ahyi Seamount, Aviation Color Code: UNASSIGNED (view)
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20230425/2104Z)
(3) Volcano: Ahyi Seamount (VNUM #284141)
(4) Current Color Code: UNASSIGNED
(5) Previous Color Code: YELLOW
(6) Source: U.S. Geological Survey
(7) Notice Number: 2023/N119
(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 diminished and nothing indicative of submarine volcanic activity has occurred for at least four weeks. Hydroacoustic detection of underwater volcanic activity has been negligible since early April 2023 and satellite observations of discolored water near the seamount were last noted in late March 2023. 

Starting mid-October 2022, 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, a combined analysis of the hydroacoustic signals and data from seismic stations located at Guam and Chichijima Island, Japan, confirmed that the source of this activity was at or near Ahyi seamount. Hydrophone signals indicative of submarine volcanic activity are no longer detected.

Due to the apparent abscence of activity, the aviation color code is being lowered from YELLOW to UNASSIGNED and the alert level is being lowered from ADVISORY to UNASSIGNED. 

 

(12) Volcanic cloud height: No volcanic cloud produced
(13) Other volcanic cloud information: Water discoloration no longer 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
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

(16) Next Notice:

A new VAN will be issued if conditions change significantly or alert levels are modified.

2023-03-21 - Kilauea, Aviation Color Code: YELLOW (view)
(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. 
 
HVO continues to closely monitor Kīlauea for signs of renewed activity. Should volcanic activity change significantly, a new Volcanic Activity Notice will be issued. 

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:

askHVO@usgs.gov

(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:

2023-03-19 - Semisopochnoi, Aviation Color Code: ORANGE (view)
(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.

2023-03-16 - Mauna Loa, Aviation Color Code: GREEN (view)
(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. 
 
Residents and visitors should stay informed and follow County of Hawai‘i and Hawaiʻi Volcanoes National Park guidelines. 

    (15) Contacts:

    askHVO@usgs.gov

    (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:

    2023-03-16 - Tanaga, Aviation Color Code: YELLOW (view)
    (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:
    2023-03-16 - Takawangha, Aviation Color Code: YELLOW (view)
    (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:
    2023-03-10 - Takawangha, Aviation Color Code: ORANGE (view)
    (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:
    2023-03-10 - Tanaga, Aviation Color Code: ORANGE (view)
    (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:
    2023-03-08 - Tanaga, Aviation Color Code: YELLOW (view)
    (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.

    Tanaga Volcano is monitored with a local seismic and infrasound network, regional infrasound and lightning detection networks, and satellite data.

    (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:
    2023-02-23 - Aniakchak, Aviation Color Code: YELLOW (view)
    (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.

    2023-02-22 - Trident, Aviation Color Code: YELLOW (view)
    (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.

    2023-02-22 - Semisopochnoi, Aviation Color Code: YELLOW (view)
    (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.

    2023-01-19 - Pavlof, Aviation Color Code: GREEN (view)
    (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:
    2023-01-06 - Kilauea, Aviation Color Code: ORANGE (view)
    (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/. 

    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 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. 

    (15) Contacts:

    askHVO@usgs.gov
     

    (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:

    2023-01-06 - Kilauea, Aviation Color Code: RED (view)
    (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 USGS Hawaiian Volcano Observatory is elevating Kīlauea’s volcano alert level from WATCH to WARNING and its aviation color code from ORANGE to RED as this eruption and associated hazards are evaluated.  

    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.

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

     

     

    (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/. 

    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 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. 

    (15) Contacts:

    askHVO@usgs.gov
     

    (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:

    2023-01-06 - Kilauea, Aviation Color Code: ORANGE (view)
    (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.

    The USGS 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.

     

     

    (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.

    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. 
     

    (15) Contacts:

    askHVO@usgs.gov
     

    (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:


     

    2023-01-05 - Cleveland, Aviation Color Code: UNASSIGNED (view)
    (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.

    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

    Pavel Izbekov, Acting Coordinating Scientist, UAFGI peizbekov@alaska.edu (907) 322-4085

    (16) Next Notice:
    2022-12-28 - Semisopochnoi, Aviation Color Code: ORANGE (view)
    (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.

    2022-12-17 - Pavlof, Aviation Color Code: YELLOW (view)
    (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:
    2022-12-13 - Mauna Loa, Aviation Color Code: YELLOW (view)
    (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. 
     
    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. 
     
    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 

    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:

      askHVO@usgs.gov
       

      (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:

      2022-12-13 - Kilauea, Aviation Color Code: YELLOW (view)
      (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. 
       
      HVO continues to closely monitor Kīlauea for signs of renewed activity. Should volcanic activity change significantly a new Volcanic Activity Notice will be issued. 

      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:

      askHVO@usgs.gov
       

      (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:


       

      2022-12-04 - Mauna Loa, Aviation Color Code: ORANGE (view)
      (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:

        askHVO@usgs.gov
         

        (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:

        2022-11-28 - Ahyi Seamount, Aviation Color Code: YELLOW (view)
        (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
        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

        (16) Next Notice:

        A new VAN will be issued if conditions change significantly or alert levels are modified.

        2022-11-28 - Mauna Loa, Aviation Color Code: RED (view)
        (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:

            askHVO@usgs.gov
             

            (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

            2022-11-28 - Mauna Loa, Aviation Color Code: RED (view)
            (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:

            askHVO@usgs.gov
             

            (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

            2022-11-23 - Semisopochnoi, Aviation Color Code: YELLOW (view)
            (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.

            2022-11-19 - Takawangha, Aviation Color Code: YELLOW (view)
            (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:
            2022-11-07 - Semisopochnoi, Aviation Color Code: ORANGE (view)
            (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.

            2022-10-19 - Trident, Aviation Color Code: GREEN (view)
            (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.

            2022-09-29 - Semisopochnoi, Aviation Color Code: YELLOW (view)
            (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.

            2022-09-29 - Trident, Aviation Color Code: YELLOW (view)
            (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.

            2022-09-20 - Shishaldin, Aviation Color Code: GREEN (view)
            (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:
            2022-08-27 - Ofu-Olosega, Aviation Color Code: GREEN (view)
            (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/)
            and select Taʻū Island from the volcano list.

            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. 
            Ken Hon, HVO Scientist in Charge, USGS khon@usgs.gov
            Natalia Deligne, American Samoa Lead Responding Scientist, USGS ndeligne@usgs.gov 

            (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.  

            2022-08-21 - Semisopochnoi, Aviation Color Code: ORANGE (view)
            (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

            2022-08-20 - Ofu-Olosega, Aviation Color Code: YELLOW (view)
            (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. 
            Ken Hon, HVO Scientist in Charge, USGS khon@usgs.gov
            Natalia Deligne, American Samoa Lead Responding Scientist, USGS ndeligne@usgs.gov 

            (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.  

            2022-08-20 - Ta'u Island, Aviation Color Code: YELLOW (view)
            (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. 
            Ken Hon, HVO Scientist in Charge, USGS khon@usgs.gov
            Natalia Deligne, American Samoa Lead Responding Scientist, USGS ndeligne@usgs.gov

            (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.   

            2022-07-08 - Semisopochnoi, Aviation Color Code: YELLOW (view)
            (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

            2022-05-11 - Cleveland, Aviation Color Code: YELLOW (view)
            (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:
            2022-04-22 - Davidof, Aviation Color Code: UNASSIGNED (view)
            (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:
            2022-04-22 - Davidof, Aviation Color Code: YELLOW (view)
            (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:
            2022-01-26 - Davidof, Aviation Color Code: YELLOW (view)
            (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:
            2021-12-29 - Davidof, Aviation Color Code: UNASSIGNED (view)
            (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:
            2021-12-10 - Davidof, Aviation Color Code: YELLOW (view)
            (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:
            2021-10-20 - Shishaldin, Aviation Color Code: UNASSIGNED (view)
            (1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
            (2) Issued: (20211020/2309Z)
            (3) Volcano: Shishaldin (VNUM #311360)
            (4) Current Color Code: UNASSIGNED
            (5) Previous Color Code: GREEN
            (6) Source: Alaska Volcano Observatory
            (7) Notice Number: 2021/A949
            (8) Volcano Location: N 54 deg 45 min W 163 deg 58 min
            (9) Area: Aleutians
            (10) Summit Elevation: 9373 ft (2857 m)
            (11) Volcanic Activity Summary: The Shishaldin Volcano monitoring network has several outages affecting local GPS, seismic, and infrasound stations that are likely to persist through the winter months. Due to the impaired local monitoring stations, the Alaska Volcano Observatory is changing the Aviation Color Code and the Volcano Alert Level to UNASSIGNED/UNASSIGNED.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

            Hazard Analysis: 

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

            Hazard Analysis: 

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



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



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


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



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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

            For discussion of Kīlauea hazards, please see:

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

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

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

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

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

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

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

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

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

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

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

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

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

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

            Satellite information, Washington VAAC
            http://www.ssd.noaa.gov/VAAC/washington.html
            (16) Next Notice:
            2021-07-28 - Gareloi, Aviation Color Code: GREEN (view)
            (1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
            (2) Issued: (20210728/1933Z)
            (3) Volcano: Gareloi (VNUM #311070)
            (4) Current Color Code: GREEN
            (5) Previous Color Code: YELLOW
            (6) Source: Alaska Volcano Observatory
            (7) Notice Number: 2021/A569
            (8) Volcano Location: