ALASKA VOLCANO OBSERVATORY DAILY UPDATE
U.S. Geological Survey
Saturday, November 18, 2023, 10:18 AM AKST (Saturday, November 18, 2023, 19:18 UTC)
Unrest continues at Shishaldin Volcano. Seismic activity remains elevated with ongoing seismic tremor and small, low-frequency earthquakes. Robust steam emissions could be seen both is satellite images as well as web camera views over the past day.
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 quiet over the past day. No unusual activity was observed in mostly cloudy satellite and web camera views over the past day.
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.
Seismic activity was low over the past day with a few small earthquakes detected. No activity was observed in cloudy satellite images.
Bogoslof volcano is monitored using a single local seismic station, distant seismic and infrasound instruments, satellite data and lightning networks. At least nine historical eruptions have been documented at Bogoslof volcano. The most recent occurred from December 2016 to August 2017 and produced seventy main explosive events that generated volcanic ash clouds that rose as high as 42,500 ft (13 km) above sea level, and that greatly modified the topography of Bogoslof Island.
Small earthquakes continue to occur near Trident and neighboring volcanoes. No current volcanic activity was observed in mostly cloudy webcam or satellite images.
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 Loewen, Acting Scientist-in-Charge, USGS firstname.lastname@example.org (907) 786-7497
David Fee, Coordinating Scientist, UAFGI email@example.com (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.