USGS Volcano Notice - DOI-USGS-AVO-2026-03-13T17:47:16+00:00

ALASKA VOLCANO OBSERVATORY WEEKLY UPDATE
U.S. Geological Survey
Friday, March 13, 2026, 11:06 AM AKDT (Friday, March 13, 2026, 19:06 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 continues to slowly erupt within the summit crater at Great Sitkin Volcano. Minor lava dome growth to the southwest and rockfalls down the south side of the dome were observed in rare clear satellite views. Minor steaming and elevated surface temperatures from the warm active lava dome were also observed when conditions allowed. Seismic activity remains low, with the detection of occasional small volcanic earthquakes and seismic signals from small rockfalls within the crater.  

The current lava eruption began in July 2021 and has filled most of the summit crater and advanced into the valleys below. There have been no explosions at Great Sitkin Volcano since an event in May 2021. The volcano is monitored using local seismic and infrasound sensors, satellite data, and web cameras, and regional infrasound and lightning networks.  

Great Sitkin Volcano is a basaltic andesite volcano that occupies most of the northern half of Great Sitkin Island, a member of the Andreanof Islands group in the central Aleutian Islands. It is located 26 miles (42 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 (1.6 km)-diameter summit crater. A steep-sided lava dome, emplaced in the crater during an eruption in 1974, has been mostly buried by the ongoing eruption. The 1974 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 also occurred in 1945, 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.

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

Signs of volcanic unrest at Shishaldin Volcano continue. Seismic and infrasound activity remain elevated, with numerous small earthquakes, frequent infrasound signals, and volcanic tremor recorded throughout the week. Daytime web camera views consistently showed minor to vigorous steaming, and sulfur dioxide gas emissions were detected in satellite data on March 6, 8 and 13.  

Strong northerly winds resuspended loose volcanic ash and dust off the ground surface and carried it to the south on March 11.  This phenomenon is not the result of the recent volcanic unrest and occurs during times of high winds and dry snow-free conditions at Shishaldin and other volcanic areas of Alaska. 

Shishaldin Volcano, located near the center of Unimak Island in the eastern Aleutian Islands, is a conical stratovolcano with a base diameter of approximately 10 miles (16 km). It is one of the most active volcanoes in the Aleutian volcanic arc, with at least 54 episodes of unrest, including over 28 confirmed eruptions since 1824. Most eruptions are relatively small, although activity during the 1999 and 2023 eruptions generated ash columns that reached up to 46,000 ft (16 km) above sea level.

CONTACT INFORMATION:

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

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

Contact AVO: https://avo.alaska.edu/contact

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.