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USGS Volcano Notice - DOI-USGS-AVO-2023-03-20T12:00:19-08:00

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ALASKA VOLCANO OBSERVATORY DAILY UPDATE
U.S. Geological Survey
Monday, March 20, 2023, 12:51 PM AKDT (Monday, March 20, 2023, 20:51 UTC)


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

Low-level seismicity continued at Semisopochnoi volcano during the past 24 hours. No explosive activity was detected in seismic or infrasound data. Clouds obscured views of the volcano by satellite and web camera.

Small eruptions producing minor ash deposits within the vicinity of the active north crater of Mount Young and ash clouds usually under 3 km (10,000 ft) above sea level have characterized the recent periods of activity. Additional ash-producing events could occur again with little warning. 

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



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

Lava continued to erupt at the summit of Great Sitkin Volcano, producing a thick lava flow within the summit crater. High resolution satellite radar data from today shows continued slow growth of the lava flow. No significant local seismicity was observed during the past 24 hours—events recorded on the seismic network there are principally from the earthquake swarm at Tanaga Island. No activity was detected in satellite and web camera imagery.

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



TANAGA (VNUM #311080)
51°53'2" N 178°8'35" W, Summit Elevation 5925 ft (1806 m)
Current Volcano Alert Level: ADVISORY
Current Aviation Color Code: YELLOW

Earthquake activity beneath Takawangha volcano and nearby Tanaga Volcano, which is about 8 km (5 miles) west of Takawangha volcano on Tanaga Island, continued over the past 24 hours. No activity was observed in satellite data. AVO continues to closely monitor the ongoing seismicity.

Increases in seismic activity have been detected previously at Tanaga Volcano and other similar volcanoes, with no subsequent eruptions. We expect additional shallow seismicity and possibly other signs of unrest, such as gas emissions, elevated surface temperatures, and surface deformation to precede any future eruption, if one were to occur.   

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



TAKAWANGHA (VNUM #311090)
51°52'1" N 178°1'37" W, Summit Elevation 4754 ft (1449 m)
Current Volcano Alert Level: ADVISORY
Current Aviation Color Code: YELLOW

Earthquake activity beneath Takawangha volcano and nearby Tanaga Volcano, which is about 8 km (5 miles) west of Takawangha volcano on Tanaga Island, continued over the past 24 hours. No activity was observed in satellite data. AVO continues to closely monitor the ongoing seismicity.

Increases in seismic activity have been detected previously at Takawangha volcano and other similar volcanoes, with no subsequent eruptions. We expect additional shallow seismicity and possibly other signs of unrest, such as gas emissions, elevated surface temperatures, and surface deformation to precede any future eruption, if one were to occur.   

Takawangha volcano is monitored by local seismic and infrasound sensors, satellite data, and regional infrasound and lightning networks.



ANIAKCHAK (VNUM #312090)
56°54'21" N 158°12'32" W, Summit Elevation 4400 ft (1341 m)
Current Volcano Alert Level: ADVISORY
Current Aviation Color Code: YELLOW

Shallow, mostly small magnitude earthquakes continued at Aniakchak volcano over the past 24 hours. No eruptive activity was observed in satellite data. 

The current period of seismic unrest began in October 2022. 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. 

AVO monitors Aniakchak with a local network, which currently consists of two functional seismometers, as well as satellite remote sensing data and regional infrasound and lightning networks.



TRIDENT (VNUM #312160)
58°14'3" N 155°6'9" W, Summit Elevation 3599 ft (1097 m)
Current Volcano Alert Level: ADVISORY
Current Aviation Color Code: YELLOW

Occasional small, shallow earthquakes continued to occur in the vicinity of Trident Volcano over the past 24 hours. No activity was seen in satellite or web camera imagery.

The current period of seismic unrest began on August 24, 2022. Increases in seismic activity have been detected previously at Trident Volcano and other similar volcanoes, with no subsequent eruptions. We expect additional shallow seismicity and other signs of unrest, such as gas emissions, elevated surface temperatures, and surface deformation to precede any future eruption, if one were to occur. 

AVO monitors Trident Volcano with a local network of seismometers, a webcam, remote sensing data, and regional infrasound and lightning networks.



OTHER ALASKA VOLCANOES

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

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

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

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CONTACT INFORMATION:

Michelle Coombs, Scientist-in-Charge, USGS mcoombs@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.