ALASKA VOLCANO OBSERVATORY DAILY UPDATE
U.S. Geological Survey
Tuesday, November 29, 2022, 12:21 PM AKST (Tuesday, November 29, 2022, 21:21 UTC)
Eruptive activity continues from a vent on the east flank of Pavlof Volcano, just below the summit. A seismic signal from a flowage event was observed yesterday evening at 17:48 AKST (2:48 UTC). Webcam images from this morning confirm a flowage deposit extending down the east flank. The flowage event resulted in a cloud of gases and possible ash up to 15,000 - 20,000 ft that was observed in webcam and satellite images. The cloud dissipated within tens of minutes.
Seismic tremor was recorded throughout the past 24 hours but no explosions were detected. Moderately elevated surface temperatures were observed in satellite data overnight.
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. Moderately elevated surface temperatures were observed in satellite data over the past day. Seismicity remains low.
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 from Semisopochnoi in clear webcam images from the past day. Clouds obscured satellite observations of the volcano. No significant seismicity was observed at the volcano over the past 24 hours.
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.
Moderately elevated surface temperatures were observed in satellite data over the past 24 hours. No significant seismic activity was observed 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 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 but has been decreasing over the past day. 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 eruptive activity has been detected in satellite views or other monitoring data.
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, firstname.lastname@example.org, (907) 786-7497
Pavel Izbekov, Acting Coordinating Scientist, UAFGI email@example.com (907) 322-4085
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