USGS Volcano Notice - DOI-USGS-AVO-2023-10-02T12:35:27-08:00

Low-level volcanic activity continues at Shishaldin Volcano. Seismicity continues at low levels and no explosions have been detected in infrasound data over the past day.  Weakly elevated surface temperatures were observed in satellite data reflecting cooling deposits from the last explosive event a week ago.

There have been eleven periods of elevated eruptive activity that resulted in significant ash emissions, edifice collapses events of the summit cone, and mass flows of volcanic debris on the volcano's flanks since the onset of the current eruption. These periods of elevated eruptive activity have been preceded by increases in seismicity in the hours to days before they occur. Additional collapse of accumulated lava near the summit crater can occur without warning and generates hot mass flows on the upper flanks and small volcanic ash clouds that dissipate quickly. The ongoing eruption started on July 12, and it is unknown how long this episode will last. However, previous eruptions of Shishaldin Volcano have lasted weeks to months with repeated cycles of 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 likely continues. Seismicity remains low with a few earthquakes detected over the past day. Cloudy conditions obscured satellite and web camera images.

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 was low with a few local earthquakes detected over the past day. No volcanic activity was noted in clear satellite or web camera images, although resuspended ash from the 1912 eruption of Katmai is visible in the region.

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.