Alaska Volcano Observatory

Activity at Great Sitkin volcano has remained unchanged over the past week, with lava continuing to erupt at a slow rate in the summit crater. Intermittent, small volcanic earthquakes continue at a low rate. Steam emissions, warm temperatures and snow-free areas were observed at the summit in satellite imagery. Minor steam emissions were also observed in webcam views.
  
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 Alaska Volcano Observatory (AVO) monitors Great Sitkin using seismic, infrasound, and satellite data.

 

Unrest persists at Mount Spurr with small, shallow earthquakes beneath the summit continuing over the past week. An AVO crew conducted an overflight of Mount Spurr on Wednesday, December 18. Gas measurements yielded similar results to those obtained on a flight on June 23, 2024, and remain consistent with typical background values. A lake that formed in the summit crater during the summer has grown indicating continued heat flow through the summit cone causing minor ice and snow melt. No other activity was observed in satellite or webcam images throughout the week.  
  
AVO is closely monitoring Mount Spurr for signs of increased unrest using local seismic, infrasound, web camera, and GNSS stations, along with regional infrasound and lightning networks and satellite data. We would expect changes in earthquakes, ground deformation, summit lake, and fumaroles if magma began to move closer to the surface. Thus, if an eruption were to occur, it would be preceded by additional signals that would allow advance warning.