USGS Volcano Notice - DOI-USGS-AVO-2023-12-06T11:11:31-09:00

Low-level activity continues at Shishaldin Volcano. Seismic activity remains elevated with small, low-frequency earthquakes observed frequently over the past day. Infrasound signals consistent with low-level explosions from Shishaldin were observed on the Okmok network on Umnal Island. Clear webcam and satellite views from the past day showed no unusual activity. 

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.

A few small earthquakes were detected under Trident and neighboring volcanoes over the past day. No volcanic activity was observed in cloudy satellite imagery. High winds yesterday afternoon in the Katmai region near Trident caused ash from the 1912 Katmai-Novarupta eruption to be resuspended and carried toward south Kodiak Island. The NWS issued a SIGMET and AVO issued an Information Statement about this non-volcanic resuspension event. 

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.