Alaska Volcano Observatory

Lava continues to erupt within the summit crater at Great Sitkin Volcano. Satellite and webcam observations have been mostly blocked by clouds, but satellite observations from November 12 show continued growth of the lava dome with an advancement over the past week of about 5 meters generally toward the south. Seismicity has been low, and occasional small earthquakes and signals related to rockfall activity continue to be detected in seismic data.

The current lava eruption began in July 2021 and has filled most of the summit crater and advanced into valleys below. There have been no explosions at Great Sitkin Volcano since an event in May 2021. The volcano is monitored using local seismic and infrasound sensors, satellite data and web cameras, and regional infrasound and lightning networks. 

Signs of volcanic unrest at Shishaldin continued this week. Low-level seismicity is ongoing, with frequent small earthquakes occurring daily. Infrasound signals were detected on most days when wind noise did not obscure them. The infrasound signals are likely caused by gas bubbles bursting through magma deep within the conduit. Satellite data show no evidence of elevated temperatures in the summit crater, indicating no lava at or near the surface. Satellite observations of SO2 over the past week had a high noise level, but suggest continued SO2 emissions. Most clear web camera views of the volcano over the past week showed steam emissions at the summit.

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network. In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to monitor the volcano.