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USGS Volcano Notice - DOI-USGS-AVO-2023-04-29T11:10:53-08:00

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ALASKA VOLCANO OBSERVATORY DAILY UPDATE
U.S. Geological Survey
Saturday, April 29, 2023, 11:47 AM AKDT (Saturday, April 29, 2023, 19:47 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

Lava likely continues to slowly erupt at the summit of Great Sitkin Volcano, producing a thick lava flow within the summit crater. Nothing significant was seen in cloudy satellite and webcam images, or in seismic data during the past day.

An eruption of lava began at Great Sitkin Volcano in July 2021 and has continued to slowly erupt since, but no explosive events have occurred during this time. An explosive event occurred in May 2021 prior to the current eruption of lava. The volcano is monitored by local seismic and infrasound sensors, satellite data, webcams, and regional infrasound and lightning networks.



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

A few partly clear web camera views of the north cone on Mount Young on Semisopochnoi showed minor steaming but no active ash emissions. Clouds obscured satellite images. A few small local earthquakes were detected over the last day but there was no evidence for explosive activity in geophysics data.

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 recent periods of eruption since 2018. Additional ash-producing events could occur again with little warning. 

Semisopochnoi volcano is monitored by local seismic and infrasound sensors, satellite data, webcams, 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

Earthquake activity beneath Aniakchak volcano continued over the past 24 hours. No eruptive activity was observed in cloudy satellite and web camera views of the volcano.

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 additional surface deformation to precede any future eruption, if one were to occur.

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



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

Elevated earthquake activity beneath Takawangha volcano and nearby Tanaga Volcano continued over the past 24 hours. No eruptive activity was observed in cloudy satellite images.

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 additional surface deformation to precede any future eruption, if one were to occur.   

Takawangha volcano and Tanaga Volcano are monitored with a local seismic and infrasound network, regional infrasound and lightning detection networks, and satellite data. Tanaga Volcano is about 5 miles (8 km) west of Takawangha volcano on Tanaga Island.



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

Elevated earthquake activity beneath Tanaga Volcano and nearby Takawangha volcano continued over the past 24 hours. No eruptive activity was observed in cloudy satellite images.

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 additional surface deformation to precede any future eruption, if one were to occur.   

Tanaga Volcano and Takawangha volcano are monitored with a local seismic and infrasound network, regional infrasound and lightning detection networks, and satellite data. Takawangha volcano is about 5 miles (8 km) east of Tanaga Volcano on Tanaga Island.



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

Earthquake activity continued in the vicinity of Trident Volcano over the last 24 hours at a rate above background levels. No volcanic activity was observed in cloudy satellite and web camera data.

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.