USGS Volcano Notice - DOI-USGS-AVO-2023-08-30T10:30:26-08:00

Low-level explosive activity is probably occurring within the summit crater of Shishaldin Volcano, based on seismic data and elevated surface temperatures visible in satellite images over the past day. No other activity has been observed.

Shishaldin has now had eight periods of elevated eruptive activity resulting in significant ash emissions and mass flows of volcanic debris on the volcano's flanks. These periods of elevated eruptive activity have been preceded by increases in seismicity in the hours before they occur. Collapse of accumulated lava near the summit crater can occur without warning and generate hot mass flows on the upper flanks and small volcanic ash clouds. The ongoing eruptive period started on July 12, and it is unknown how long this eruptive episode will last. However, previous eruptions of Shishaldin Volcano have lasted weeks to months with repeated cycles of activity like those seen over the last month.

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 likely continues within the summit crater of Great Sitkin Volcano. Occasional earthquakes continue. Satellite and webcam views were obscured by clouds over the past day.

The current lava flow at Great Sitkin Volcano 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 near Trident Volcano remained slightly elevated over the past day. Satellite and web camera images were obscured by clouds.

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.   AVO issued an Information Statement on July 25 providing a more detailed update on the volcanic unrest at Trident Volcano and the broader Katmai volcanic cluster (https://www.avo.alaska.edu/news.php?id=1595).

Trident Volcano is monitored by local seismic sensors, web cameras, regional infrasound and lightning networks, and satellite data.