USGS Volcano Notice - DOI-USGS-AVO-2023-08-15T12:35:22-08:00

Seismic activity at Aniakchak volcano remained low over the past day.  No activity was observed in clear to cloudy satellite and web camera views.

The current period of seismic unrest began in October 2022. Increases in seismic activity have been detected previously at other similar volcanoes, with no subsequent eruptions. We expect additional shallow seismicity and other signs of unrest, such as gas emissions, elevated surface temperatures, and additional surface deformation to precede any future eruption if one were to occur.

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

A vigorous eruption of Shishaldin Volcano occurred at about 02:00 AKDT (10:00 UTC). An ash cloud, visible in satellite data, extended northeast of the volcano about 100 km. The ash cloud may have reached as high as 36,000 feet above sea level as it drifted northeast over the Bering Sea. A sulfur dioxide cloud associated with the eruption may still be present over the southern Bering Sea. Strong volcanic tremor and explosions characterized the eruption as detected in seismic and infrasound data. Several incidents of volcanic lightning were detected as well. Seismicity was significantly elevated during the eruption but has since declined to levels indicative of ongoing low-level eruptive activity, and recent pilot reports indicate ash emissions are continuing up to 16,000 feet above sea level. Elevated surface temperatures were observed in satellite images, but clouds obscured the volcano, and nothing was visible in web camera views.

Shishaldin has had seven periods of elevated eruptive activity (including this event), resulting in significant ash emissions. 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 similar to those seen over the last month.

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a geodetic network. In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

Seismicity was low at Cleveland volcano over the past day. No activity was observed in cloudy satellite and web camera views.

Episodes of lava effusion and explosions can occur without advance warning. Explosions from Mount Cleveland are normally short-duration and only present a hazard to aviation in the immediate vicinity of the volcano. Larger explosions that present a more widespread hazard to aviation are possible but are less likely and occur less frequently.

Cleveland volcano is currently monitored by a local seismic network, infrasound sensors, and web cameras. In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite observations to detect eruptions. Based on past events, explosive eruptions of Cleveland may occur with little or no warning. Rapid detection of an ash-producing eruption may be possible using a combination of seismic, infrasound, web camera, lightning, and satellite data.

Slow eruption of lava continues within the summit crater of Great Sitkin Volcano. Earthquake activity remains slightly elevated over the past day.  No significant activity was observed in cloudy webcam and satellite views of the volcano.

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.

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

Seismic activity near Trident Volcano remained slightly elevated over the past day. No activity was observed in clear to cloudy satellite images and web camera views.

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.