ALASKA VOLCANO OBSERVATORY DAILY UPDATE
U.S. Geological Survey
Wednesday, October 12, 2022, 1:10 PM AKDT (Wednesday, October 12, 2022, 21:10 UTC)
Low-level eruptive activity continues from a vent on the east flank, just below the summit of Pavlof Volcano. Clear webcam images captured very small ash emissions and lava in the immediate vicinity of the vent. Seismic tremor and multiple small explosions was detected 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.
Low-level eruption of lava continues at Great Sitkin Volcano. Seismicity remained at low levels with a few small local earthquakes detected over the past day. No activity was observed in cloudy satellite and web camera data.
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. A few small earthquakes but no explosions were detected over the past day. Clear webcam images showed typical steam emissions from North Cerberus crater.
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.
Connection to data from local seismic stations at Cleveland was restored yesterday. No significant seismic activity was observed, and satellite data were obscured by clouds.
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.
No significant earthquakes or surface activity was observed in the last day.
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.
OTHER ALASKA VOLCANOES
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Michelle Coombs, Scientist-in-Charge, USGS, email@example.com, (907) 786-7497
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