Alaska Volcano Observatory

Lava continues to slowly erupt within the summit crater at Great Sitkin Volcano. Satellite data on January 13 confirmed that the lava dome is slowly inflating towards the southeast, with minor rockfalls occurring along this growing edge. All week clouds obscured images of the volcano. Seismic activity remains low, with only occasional small earthquakes and rockfalls detected.

The current eruption of lava 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.

A notable increase in the rate of long-period earthquakes started on January 14 at 12:45 am AKST (09:45 UTC). This activity prompted an increase of the Aviation Color Code and Volcano Alert Level to YELLOW/ADVISORY. Clear satellite and webcam images the following days did not show any evidence for surface changes or activity. The earthquake activity has also decreased to background levels over the last two days.

Increases in this type of earthquake activity in the past have preceded eruptions, but also have ended without an eruption occurring. Eruptions at Pavlof Volcano have also occurred with little or no precursor activity.

The Alaska Volcano Observatory will continue to closely monitor Pavlof Volcano data to confirm if the period of elevated activity has ended. The volcano is monitored by local seismic and infrasound sensors, satellite data, web cameras, and regional infrasound and lightning networks. 

Signs of volcanic unrest at Shishaldin Volcano continued this week. Web camera images, when clear, showed a plume of gas rising from the summit crater. Low-level seismic activity has persisted, with small earthquakes occurring frequently. Infrasound signals, likely caused by gas bubbles bursting deep within the volcanic vent, were also detected throughout the week when the conditions were not too windy. At this time, there is no evidence of lava at the surface.

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