USGS Volcano Notice - DOI-USGS-AVO-2022-05-16T14:59:16-08:00

Satellite data and web camera views show slow growth of lava flows from the summit crater consistent with continued lava effusion. No significant seismic activity was detected over the last day. 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.

Elevated surface temperatures were observed in satellite images over the last day consistent with a continued low-level eruption and effusion of short lava flows on the upper flank. Seismic tremor continues but no explosions or ash emissions were detected.

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 eruptive activity continues. Seismicity remains elevated with intermittent tremor and earthquakes.  Several explosions were detected in seismic and infrasound data over the last day. Clear satellite and web camera images showed low-level ash emissions.

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.

Satellite data over the last day detected a continuous sulfur dioxide plume extending 500 km from the volcano. No significant seismic or infrasound activity was detected.

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.