USGS Volcano Notice - DOI-USGS-AVO-2023-07-02T10:53:57-08:00

Slow eruption of lava continues at Great Sitkin Volcano, where it is producing a thick lava flow within the summit crater. Elevated surface temperatures and a steam plume were observed in partly cloudy satellite views, whereas webcam views were mostly obscured by clouds over the past day. Moderate resolution satellite radar imagery showed continued movement of the lava flow to the east within the summit crater. Low-level seismic activity is also occuring with small earthquakes detected.

An eruption of lava began at Great Sitkin Volcano in July 2021 and has continued to slowly erupt since, but no explosive events have occurred. An explosive event occurred in May 2021, before the current eruption of lava. The volcano is monitored by local seismic and infrasound sensors, satellite data, webcams, and regional infrasound and lightning networks.

Seismic activity was low at Aniakchak volcano over the past day. No noteworthy activity was observed in cloudy satellite and webcam 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.

AVO currently monitors Aniakchak with satellite remote sensing data, regional infrasound and lightning networks and several regional seismometers. The local seismic network has been struggling with power issues during the past week. 

No evidence of explosive activity was observed in geophysical or remote sensing data over the past day. A weak steam plume was observed from the north crater of Mount Young in partly cloudy webcam imagery. Otherwise nothing significant was seen in partly cloudy to clear satellite images of the volcano. Seismicity remains elevated.

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. Additional ash-producing events could occur again with little warning. 

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

Earthquakes continued to occur beneath Tanaga Island over the past day. No activity was observed in partly cloudy satellite images and web camera views.

Increases in seismic activity have been detected previously at Takawangha volcano and other similar volcanoes, with no subsequent eruptions. We expect additional shallow seismicity and possibly 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.   

Takawangha volcano and Tanaga Volcano are monitored with a local seismic and infrasound network, regional infrasound and lightning detection networks, and satellite data. Tanaga Volcano is about 5 miles (8 km) west of Takawangha volcano on Tanaga Island.

Earthquakes continued to occur beneath Tanaga Island over the past day. No activity was observed in partly cloudy satellite images and web camera views.

Increases in seismic activity have been detected previously at Tanaga Volcano and other similar volcanoes, with no subsequent eruptions. We expect additional shallow seismicity and possibly 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.   

Tanaga Volcano and Takawangha volcano are monitored with a local seismic and infrasound network, regional infrasound and lightning detection networks, and satellite data. Takawangha volcano is about 5 miles (8 km) east of Tanaga Volcano on Tanaga Island.

Small earthquakes near Trident Volcano continued to occur at a moderate rate over the past day. No noteworthy activity was observed in partly 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, with no subsequent eruptions. We expect additional shallow seismicity and other signs of unrest, such as gas emissions, elevated surface temperatures, and surface deformation, to precede any future eruption if one were to occur. 

AVO monitors Trident Volcano with a local network of seismometers, a webcam, remote sensing data, and regional infrasound and lightning networks.