ALASKA VOLCANO OBSERVATORY DAILY UPDATE
U.S. Geological Survey
Sunday, December 3, 2023, 11:25 AM AKST (Sunday, December 3, 2023, 20:25 UTC)
Activity continues at Shishaldin Volcano. Seismic activity remains elevated with small, low-frequency earthquakes observed frequently over the past day. Small explosions were also observed in infrasound data when the wind noise is low. Partly cloudy satellite and webcam imagery showed weakly elevated surface temperatures and a persistent steam and gas plume from the summit and collapse scarps on the volcano's upper flanks. No ash emissions observed.
Thirteen significant explosive events have occurred at Shishaldin since July 12 through October 3, 2023. These events have been preceded by increases in seismicity in the hours to days before they occur. It is unknown how long this period of ongoing activity will last. However, previous eruptions of Shishaldin Volcano have lasted weeks to months with repeated cycles of eruptive activity like those seen since July.
Local seismic and infrasound sensors, web cameras, and a geodetic network 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.
Slow eruption of lava in the summit crater of Great Sitkin Volcano continues. Seismic activity was low over the past day. Clouds obscured views of the active lava flow in satellite and web camera imagery.
The current lava flow began erupting in July 2021. No explosive events have occurred since a single event in May 2021.
Local seismic and infrasound sensors, web cameras, regional infrasound and lightning networks, and satellite data are used to monitor the volcano.
Earthquake activity near Trident and neighboring volcanoes was quiet over the past day. No activity was observed in mostly cloudy satellite imagery.
The current period of seismic unrest began in August 2022. Increases in seismic activity have been detected previously at Trident Volcano and other similar volcanoes and did not result in eruptions. We expect additional shallow seismicity and other signs of unrest, such as gas emissions, elevated surface temperatures, and ground movement, to precede any future eruption if one were to occur.
Trident Volcano is monitored by local seismic sensors, web cameras, regional infrasound and lightning networks, and satellite data.
Matt Haney, Scientist-in-Charge, USGS mhaney@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.
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