USGS Volcano Notice - DOI-USGS-AVO-2025-12-23T20:46:09+00:00

ALASKA VOLCANO OBSERVATORY DAILY UPDATE
U.S. Geological Survey
Tuesday, December 23, 2025, 11:49 AM AKST (Tuesday, December 23, 2025, 20:49 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 erupt slowly within the summit crater of Great Sitkin Volcano. Nothing unusual was observed in partly cloudy satellite and webcam views. Seismicity was mostly quiet over the past day.

The current lava eruption began in July 2021 and since then has filled most of the summit crater and advanced into 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.

To view monitoring data and other information about Great Sitkin: https://avo.alaska.edu/volcano/great-sitkin

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

Shishaldin Volcano continues to experience unrest with occasional small earthquakes detected throughout the day yesterday. Nothing unusual was observed in mostly clear satellite and webcam views. Lenticular clouds over the summit prevented any view of potential weak steaming.

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.

To view monitoring data and other information about Shishaldin: https://avo.alaska.edu/volcano/shishaldin

CONTACT INFORMATION:

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

Jessica Larsen, Acting Coordinating Scientist, UAF jflarsen@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.