ALASKA VOLCANO OBSERVATORY DAILY UPDATE
U.S. Geological Survey
Thursday, October 20, 2022, 10:50 AM AKDT (Thursday, October 20, 2022, 18:50 UTC)
Low-level eruptive activity continues from a vent on the east flank of Pavlof Volcano, just below the summit. Seismic tremor and several small explosions were detected over the past day. During these explosions, incandescence near the summit could be seen in web camera views. Elevated surface temperatures were observed in satellite views over the past day.
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 continues to erupt in the summit crater of Great Sitkin Volcano. No unusual activity observed in satellite and web camera views over the past day. No significant seismicity was detected over the past day.
The terrain is steep near the terminus of the current eruption's lava flows, and blocks of lava could detach without warning and form small rock avalanches in these valleys. These avalanches may liberate ash and gas and could travel several hundred meters beyond the lava flows; they would be hazardous to anyone in those areas.
Great Sitkin Volcano is monitored by local seismic and infrasound sensors, satellite data, web cameras, and regional infrasound and lightning networks.
Low-level eruption at Semisopochnoi volcano is currently paused. No explosions or significant seismic activity were detected over the past day. Clouds obscured most satellite and web camera views over the past day.
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.
No significant seismic activity was observed over the past 24 hours. Cloudy conditions obscured satellite views over the past day.
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 two 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 swarm of earthquakes that began on August 24, 2022, beneath Trident Volcano has subsided and seismic tremor has not been observed since September 30, 2022. Occasional local earthquakes continue to be detected at background levels. Due to this decrease in activity and the absence of other signs of unrest, AVO lowered the Aviation Color Code to GREEN and the Volcano Alert level to NORMAL on Wednesday, October 19, 2022.
Should activity increase, AVO will issue further notices. AVO monitors Trident Volcano with a local network of seismometers, a webcam, remote sensing data, and regional infrasound and lightning networks.
OTHER ALASKA VOLCANOES
Information on all Alaska volcanoes is available at: http://www.avo.alaska.edu.
For definitions of Aviation Color Codes and Volcano Alert Levels, see: http://www.avo.alaska.edu/color_codes.php
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Michelle Coombs, Scientist-in-Charge, USGS, firstname.lastname@example.org, (907) 786-7497
David Fee, Coordinating Scientist, UAFGI, email@example.com, (907) 378-5460
The Alaska Volcano Observatory is a cooperative program of the U.S. Geological Survey, the University of Alaska Fairbanks Geophysical Institute, and the Alaska Division of Geological and Geophysical Surveys.