ALASKA VOLCANO OBSERVATORY DAILY UPDATE
U.S. Geological Survey
Saturday, July 23, 2022, 10:48 AM AKDT (Saturday, July 23, 2022, 18:48 UTC)
Pavlof Volcano continues to erupt from the vent on the volcano’s east flank just below the summit. Elevated surface temperatures were observed in satellite views of the volcano over the past day, and seismic tremor and multiple small explosions were detected in local seismic and infrasound data, as well as on regional stations. Slightly larger explosion signals were detected mid-day yesterday and correlated with a low-level ash cloud that reached to about 8,600 ft above sea level and was reported by passing aircraft.
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 can change quickly and the progression to more significant eruptive activity can occur with little or no warning.
Pavlof is monitored by local seismic and infrasound sensors, satellite data, web cameras, and remote infrasound and lightning networks.
Low-level eruption of lava continues at Great Sitkin. Seismicity remains low with occasional local earthquakes over the past day. Satellite and webcam views of the volcano were blocked by clouds. It is possible that new explosive activity could occur with little or no warning.
Great Sitkin is monitored by local seismic and infrasound sensors, satellite data, web cameras, and remote infrasound and lightning networks.
Low-level unrest continues. Seismicity remains low with occasional local earthquakes, although no explosions were detected in the past day. Clouds blocked satellite views of the volcano, but steam emissions were seen in a webcam images.
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 may continue and could be difficult to detect, especially when thick cloud cover obscures the volcano.
Semisopochnoi is monitored by local seismic and infrasound sensors, satellite data, web cameras, and remote infrasound and lightning networks.
Unrest continues at Cleveland. No significant activity was detected on local or regional seismic and infrasound networks. Satellite views of the volcano were obscured by clouds.
Episodes of lava effusion and explosions can occur without advance warning. Explosions from 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 operational, Cleveland volcano 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.
OTHER ALASKA VOLCANOES
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Michelle Coombs, Scientist-in-Charge, USGS firstname.lastname@example.org (907) 786-7497
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