USGS Volcano Notice - DOI-USGS-AVO-2025-07-29T19:36:26+00:00

Lava continues to erupt in the summit crater of Great Sitkin Volcano. Low-level seismicity continues with occasional small earthquakes and rockfall signals. Webcam and satellite views showed minor steaming from the active lava flow, which has steep unstable margins that generate small rockfalls.

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.

Low-level unrest continues at Mount Spurr. Seismic activity was low over the past day. Typical weak steaming from the summit crater fumaroles (steam and gas vents) was observed in clear web camera views over the past day. Carbon dioxide gas emissions from Crater Peak continue to be detected by a gas monitoring instrument on the crater rim.

Fluctuations in unrest are common at volcanoes and eruptive activity remains possible, but unlikely. Should unrest escalate towards an eruption, we expect to observe increases in seismic activity, gas emissions, surface deformation, and surface heating.

The volcano is monitored using local seismic, infrasound, web camera, and GNSS (GPS) stations along with regional infrasound, lightning networks, and satellite data.