USGS Volcano Notice - DOI-USGS-AVO-2023-11-28T08:40:52-09:00

Slow eruption of lava in the summit crater of Great Sitkin Volcano continues. Seismic activity was quiet over the past day. No activity was observed in mostly cloudy satellite and web camera views.

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.

Unrest continues at Shishaldin Volcano over the past day. Seismic activity remains elevated with small, low-frequency earthquakes and small explosions observed in seismic and local infrasound data. No activity was observed in partly cloudy satellite views. Steaming from the summit was observed in some clear webcam images, with schmutzy snow visible on the north side of the volcano.

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.

Earthquake activity near Trident and neighboring volcanoes was low over the past day. Weakly elevated surface temperatures were observed in satellite imagery. Web camera views were obscured by snow. 

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.