USGS Volcano Notice - DOI-USGS-AVO-2023-10-19T09:41:36-08:00

Volcanic unrest continues at Shishaldin Volcano. Seismic activity remains elevated and consists of seismic tremor and small, low-frequency earthquakes. Sulfur dioxide gas emissions were seen again in satellite data yesterday. Elevated surface temperatures were evident in satellite images throughout the past day; however, thermal output is not consistent with new lava at the surface. Webcam views showed light steaming in the summit area when not obscured by clouds. These current observations are all consistent with magma degassing at fairly shallow levels beneath the volcano. 

Twelve significant explosive events have occurred at Shishaldin since July 12, 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 likely continues. Earthquake activity remained low over the past day, with only a few small quakes detected. Satellite and web-camera views were obscured by clouds. 

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.

There was a slight increase in earthquake activity near Trident and neighboring Katmai area volcanoes over the past 24 hours. This includes a M2.4 quake near Mount Mageik, about 15 km (9 miles) southwest of Trident.  No volcanic activity was observed in mostly clear webcam or satellite images over the past 24 hours. 

The current period of seismic unrest began on August 24, 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.