USGS Volcano Notice - DOI-USGS-AVO-2023-08-02T12:37:29-08:00

Low-level eruptive activity continues within the summit region of Shishaldin Volcano with low-level ash emissions. Elevated surface temperatures have been observed over the past several days, consistent with cooling lava, but over the last 24 hours these temperatures have increased.  Seismicity continues to be low, however a few episodes of volcanic tremor were observed, consistent with low-level ash production.  Volcanic ash was observed below 10,000 ft a.s.l. up to 50 nautical miles north of Shishaldin Volcano.

Shishaldin has had five periods of elevated eruptive activity resulting in significant ash emission during the current eruption which started on July 12.  It is unknown how long this eruption will last, but previous eruptions of Shishaldin Volcano have lasted weeks to months with repeated cycles of activity similar to those seen in the last two weeks.

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered 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.

Slow eruption of lava continues at Great Sitkin Volcano, where it is producing a thick lava flow within the summit crater. The eastern lobe of this flow continues to advance.  Earthquake activity remains slightly elevated over the past day.  Clouds obscured views of the volcano by satellite and web camera.

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 at Cleveland volcano has waned over the past day with no earthquakes detected. Cloudy conditions obscured satellite views over the past day, but occasional clear web camera views showed weak steaming from the summit.

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 with a five-station real-time seismic network and three nearby web cameras. 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.

Seismic activity near Trident Volcano remained elevated including numerous deep low-frequency earthquakes and tremor over the past day. These types of earthquakes often indicate the movement of magma or magmatic fluids beneath the ground. No activity was observed in partly cloudy satellite 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.

Seismicity remains slightly elevated at Aniakchak volcano with a few earthquakes detected over the past day. No activity was observed in partly 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.

Seismicity at Semisopochnoi Island is low with no earthquakes detected over the past day. Clouds obscured views of the volcano by satellite.  Minor steam emissions were observed in occasional clear web camera views.

Small eruptions producing minor ash deposits within the vicinity of the active north crater of Mount Young and ash clouds usually under 10,000 ft. (3 km) above sea level have characterized recent periods of eruption since 2018. The last evidence of ash emission from the volcano was on May 5, 2023, and consisted of a minor dusting of ash on the northwest flank of the north crater of Mount Young. Additional ash-producing events could occur again with little or no warning. 

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