Alaska Volcano Observatory

Activity at Great Sitkin Volcano continued over the past week, characterized by the slow eruption of lava in the summit crater. Satellite radar data through March 6 shows ongoing slow growth of the lava flow. Intermittent, small volcanic earthquakes continue to occur. The volcano has been obscured by clouds in satellite and web camera views all week. 

Since the May 2021 explosion, there have been no other explosions at Great Sitkin Volcano. The lava eruption that began in July 2021 is ongoing. It has filled most of the summit crater and advanced into valleys below. The volcano is monitored using local seismic and infrasound sensors, satellite data and web cameras, and regional infrasound and lightning networks.

Volcanic unrest continues at Mount Spurr volcano and is characterized by ongoing earthquake activity, surface deformation, and volcanic gas emissions. Seismicity remains elevated and increased slightly compared to last week. Over the past week, 145 earthquakes were located, most in the summit region and fewer near Crater Peak. No unusual activity was observed in satellite or webcam data, although minor steam emissions from the summit of the volcano were sometimes seen from nearby communities during periods of clear weather. Overflights on March 7 and 11 to measure volcanic gases found elevated levels of SO₂ and CO₂ being emitted from the summit of Mount Spurr and CO₂ being emitted from Crater Peak. Reactivated gas vents were also observed within the crater at Crater Peak. AVO released an Information Statement earlier this week that discusses these observations and more. The Mount Spurr monitoring network is functioning well, although the web camera at station CKT remains obscured by snow and ice. 

AVO continues to closely monitor activity at Mount Spurr for signals indicating the volcano is moving closer to an eruption using local seismic, infrasound, and GNSS stations, web cameras, regional infrasound, lightning networks, and satellite data. Based on previous eruptions, additional changes in earthquakes, ground deformation, the summit lake, and fumaroles would be expected if magma moves closer to the surface. Therefore, if an eruption occurred, it would be preceded by additional signals that would allow advance warning.