Increased seismic activity, Alert Level raised for Bogoslof volcano, Alaska

Increased seismic activity has been recorded at Bogoslof volcano in Alaska since October 21, 2023, leading authorities to raise the alert level.

In the span from October 21 to October 24, 2023, more than 90 earthquakes were detected around Bogoslof Volcano, the Alaska Volcano Observatory said in the Volcanic Activity Notice issued at 22:55 UTC on October 24, 2023. This heightened activity has led to the Aviation Color Code and Volcano Alert Level being raised to Yellow/Advisory.

Seismic increases like these often come before eruptions, although not all volcanoes with similar patterns erupt. Despite the flurry of seismic activity, satellite data has shown no other signs of unrest in the past several days.

Monitoring of Bogoslof Volcano is conducted through a single local seismic station, distant seismic and infrasound instruments, satellite data, and lightning detection.

Historically, the volcano has erupted nine times. Its most recent eruption series spanned from December 2016 to August 2017 (VEI 3), involving 70 main explosive events. These eruptions generated volcanic ash clouds reaching up to 13 km (42 500 feet) above sea level and significantly altered the topography of Bogoslof Island.

The volcano is situated approximately 98 km (61 miles) northwest of Unalaska/Dutch Harbor, 123 km (76 miles) northeast of Nikolski, and 149 km (93 miles) northeast of Akutan. It falls within the jurisdiction of the U.S. Fish and Wildlife Service Alaska Maritime National Wildlife Refuge and serves as a habitat for marine mammals and seabirds.

References:

¹ AVO/USGS Volcanic Activity Notice for Bogoslof volcano – USGS/AVO – October 24, 2023

Featured image: Bogoslof volcano on October 1, 2023. Credit: Copernicus EU/Sentinel-2, EO Browser, The Watchers

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