Blowing its top: an explanation of Bogoslof Volcano's eruptions, latest on Thursday

 Photo courtesy Alaska Volcano Observatory/U.S. Geological Survey
Photo courtesy Alaska Volcano Observatory/U.S. Geological Survey (KTUU)
Published: Jan. 5, 2017 at 3:12 PM AKST
Email This Link
Share on Pinterest
Share on LinkedIn

In mid-December, the alerts started. The Alaska Volcano Observatory sent out an activity notice Dec. 20, after several pilots reported seeing an ash cloud near Bogoslof Volcano in the Aleutian chain. Since then, it's erupted at least a dozen times, most recently prompting a "Red" aviation alert Thursday.

AVO writes that it detected an "escalation in seismicity" around 1:24 p.m. Thursday, along with lightning strikes.

Bogoslof is a submarine stratovolcano, according to AVO. And while it measures about 5,000 ft. from the Bering Sea floor, only a few hundred feet extends above sea level, according to geophysicist Dave Schneider. Bogoslof has been erupting since the late 1700s.

"These last anywhere form weeks to months at a time, and this kind of explosive activity is very common for Bogoslof," Schneider said. "You see on the map that it's greatly re-shaped the island."

The change in landscape, remote location and sensitive habitat make it difficult to have equipment on the island. It is also part of the Alaska Maritime Wildlife refuge, and an important place for seals and birds. Instead, AVO uses seismic sensors on nearby volcanoes, along with pressure sensors throughout Alaska to monitor Bogoslof's activity.

"As of today, the volcano remains restless," Schneider said. "We really can't say if the eruption is over at this point, but we are watching it closely."