ALASKA VOLCANO OBSERVATORY DAILY UPDATE
U.S. Geological Survey
Sunday, September 3, 2023, 11:33 AM AKDT (Sunday, September 3, 2023, 19:33 UTC)
Low-level explosive activity is likely occurring within the summit crater of Shishaldin Volcano. Wind has increased and is masking the local infrasound data that yesterday showed signals of small repetitive explosions. Seismic activity continues and elevated surface temperatures in the summit crater were observed in several satellite images through thin clouds. Web camera images show the summit cloaked in clouds this morning.
Shishaldin has now had eight periods of elevated eruptive activity resulting in significant ash emissions and mass flows of volcanic debris on the volcano's flanks. These periods of elevated eruptive activity have been preceded by increases in seismicity in the hours before they occur. Collapse of accumulated lava near the summit crater can occur without warning and generate hot mass flows on the upper flanks and small volcanic ash clouds. The ongoing eruptive period started on July 12, and it is unknown how long this eruptive episode will last. However, previous eruptions of Shishaldin Volcano have lasted weeks to months with repeated cycles of activity like those seen over the last month.
Local seismic and infrasound sensors, web cameras, and a geodetic network monitor Shishaldin Volcano. In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.
Slow eruption of lava in the summit crater continues. Seismicity is low with only one earthquake detected over the past day. Satellite and web camera observations were mostly obscured by clouds.
The current lava flow at Great Sitkin Volcano began erupting in July 2021. No explosive events have occurred since a single event in May 2021.
Local seismic and infrasound sensors, web cameras, regional infrasound and lightning networks, and satellite data are used to monitor the volcano.
Seismic activity near Trident Volcano increased over the past day with numerous small earthquakes detected. Short-term increases in seismicity are common during periods of unrest at volcanoes and at this point does not represent a significant change. Satellite observations were obscured by clouds and no activity was seen in web camera images during periods of clear viewing conditions.
The current period of seismic unrest began on August 24, 2022. Increases in seismic activity have been detected previously at Trident Volcano and other similar volcanoes and did not result in eruptions. We expect additional shallow seismicity and other signs of unrest, such as gas emissions, elevated surface temperatures, and ground movement, to precede any future eruption if one were to occur. AVO issued an Information Statement on July 25 providing a more detailed update on the volcanic unrest at Trident Volcano and the broader Katmai volcanic cluster (https://www.avo.alaska.edu/news.php?id=1595).
Trident Volcano is monitored by local seismic sensors, web cameras, regional infrasound and lightning networks, and satellite data.
Matt Haney, Scientist-in-Charge, USGS firstname.lastname@example.org (907) 786-7497
David Fee, Coordinating Scientist, UAFGI email@example.com (907) 378-5460
The Alaska Volcano Observatory is a cooperative program of the U.S. Geological Survey, the University of Alaska Fairbanks Geophysical Institute, and the Alaska Division of Geological and Geophysical Surveys.
This website is supported by the U.S. Geological Survey under Cooperative Agreement Grant G22AC00137
Mention of trade names or commercial products does not constitute their endorsement by the U.S. Geological Survey.