ALASKA VOLCANO OBSERVATORY DAILY UPDATE
U.S. Geological Survey
Tuesday, December 20, 2022, 11:06 AM AKST (Tuesday, December 20, 2022, 20:06 UTC)
No eruptive explosions or lava flow activity was detected in seismic, infrasound, satellite, or web camera data over the last day. Seismicity remains above background with a few episodes of weak seismic tremor.
Small explosions associated with the current eruption could happen at any time and may be accompanied by small ash plumes within the immediate vicinity of the volcano. The level of unrest at Pavlof Volcano can change quickly and the progression to more significant eruptive activity can occur with little or no warning.
Pavlof Volcano is monitored by local seismic and infrasound sensors, satellite data, web cameras, and regional infrasound and lightning networks.
Lava most likely continued to erupt in the summit crater of Great Sitkin Volcano over the last day. No significant activity was observed in seismic data or in clear satellite or web camera views.
Great Sitkin Volcano is monitored by local seismic and infrasound sensors, satellite data, web cameras, and regional infrasound and lightning networks.
No activity was observed over the past day. Clouds obscured satellite and web camera views and no significant seismic activity was detected.
Small eruptions producing minor ash deposits within the vicinity of the active north crater of Mount Cerberus and ash clouds usually under 10,000 ft (3 km) above sea level have characterized the recent activity. Small explosions and associated ash emissions could resume and may be difficult to detect during periods of high winds and/or when thick cloud cover obscures the volcano. Ash emissions over the past several years of activity have typically reached altitudes of less than 10,000 ft (3 km) above mean sea level.
Semisopochnoi volcano is monitored by local seismic and infrasound sensors, satellite data, web cameras, and regional infrasound and lightning networks.
Clouds obscured satellite and web camera views of the summit over the past day. No earthquake activity was detected on local monitoring stations.
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.
When the seismic network is operational, Mount Cleveland is monitored by only three local seismic stations, which restricts AVO's ability to precisely locate earthquakes and detect precursory unrest that may lead to an explosive eruption. Rapid detection of an ash-producing eruption may be possible using a combination of seismic, infrasound, lightning, and satellite data.
The ongoing earthquake swarm near Takawangha volcano is continuing over the last 24 hours. The earthquakes are generally shallow, having preliminary depths of about 2 to 7 miles (3 to 11 km) below sea level. This activity may be due to the movement of magma beneath the volcano. No other signs of unrest were observed in partly clear satellite views.
OTHER ALASKA VOLCANOES
Information on all Alaska volcanoes is available at: http://www.avo.alaska.edu.
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Michelle Coombs, Scientist-in-Charge, USGS, email@example.com, (907) 786-7497
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