USGS Volcano Notice - DOI-USGS-AVO-2024-09-13T18:55:01+00:00

ALASKA VOLCANO OBSERVATORY WEEKLY UPDATE
U.S. Geological Survey
Friday, September 13, 2024, 12:00 PM AKDT (Friday, September 13, 2024, 20:00 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

No major change occurred this week at Great Sitkin Volcano. The ongoing eruption continues to slowly fill the summit crater with lava. A September 10 satellite radar image shows that the current eruption is feeding an active lobe of lava in the eastern part of the summit crater. AVO's seismic network has detected rockfalls from the advancing northern part of this lobe throughout the week. The current eruption is also causing frequent, small volcanic earthquakes. When the weather was clear, satellite images showed elevated temperatures from the active lava flow surface.

The current lava eruption at Great Sitkin Volcano began in July 2021. AVO has mainly used satellite radar images that can view the volcano through cloud cover to track the eruption. A single explosive event occurred in May 2021, and no other explosions have been detected since.  

Great Sitkin Volcano is a basaltic andesite volcano that occupies most of the northern half of Great Sitkin Island, a member of the Andreanof Islands group in the central Aleutian Islands. It is located 26 miles (43 km) east of the community of Adak. The volcano is a composite structure consisting of an older dissected volcano and a younger parasitic cone with a ~1 mile (1.5 km)-diameter summit crater. A steep-sided lava dome, emplaced during the 1974 eruption, occupies the center of the crater. That eruption produced at least one ash cloud that likely exceeded an altitude of 25,000 ft (7.6 km) above sea level. A poorly documented eruption occurred in 1945, also producing a lava dome that was partially destroyed in the 1974 eruption. Within the past 280 years a large explosive eruption produced pyroclastic flows that partially filled the Glacier Creek valley on the southwest flank.

CONTACT INFORMATION:

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

David Fee, Coordinating Scientist, UAF 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.