The three Aleutian volcanoes that have been erupting simultaneously in recent months could be joined by a fourth. Davidof Volcano in the Western Aleutians has remained inactive for thousands of years. But a series of earthquakes measured around the dormant volcano has some researchers wondering if Davidof is waking up.
The remnant of an ancient caldera, Davidof rises over 1,000 feet out of the Bering Sea. It’s located in the Rat Islands in the far Western Aleutians, nearly 200 miles west of Adak — so far west that it’s in the Eastern Hemisphere.
The volcano hasn’t been active at least since the time Russian explorers started keeping records in 1760. Researchers say it has likely remained dormant for much longer than that, perhaps as long as 10,000 years.
But a swarm of earthquakes shook the area beginning Dec. 7, and that has researchers keeping a close watch.
Matthew Haney is a geophysicist with the Alaska Volcano Observatory in Anchorage. He said that even though Davidof is not considered historically active, “the process of subduction that leads to volcanoes along the Aleutian Arc hasn’t stopped,” and “the possibility remains for there to be activity.”
He says the earthquakes increased in magnitude over the week, which could suggest the earthquakes weren’t caused by tectonic shifts, but rather by magma flowing beneath the volcano.
“With tectonic earthquakes, typically the first one is the largest one, and then there’s a bunch of aftershocks afterwards. So I think this one caught our attention last week because the largest earthquake was not the first one,” Haney said. “So that is something that catches our attention that’s more like a volcanic earthquake sequence.”
Davidof is too remote to threaten any communities, but Haney says it could pose a hazard to airline traffic. AVO raised the warning level at Davidof to yellow last Friday due to that possibility.
Haney says that in 2008, a similar string of earthquakes hit an area east of Adak around Kasatochi Volcano.
“A similar question arose: are these earthquakes that we’re measuring tectonic or volcanic? And in that case, the earthquake activity intensified and the volcano ultimately erupted in 2008 in a large eruption,” Haney said.
The earthquakes around Davidof continued through the weekend, but they don’t seem to be intensifying.
Still, Haney says, AVO’s team will be keeping a close watch from their vantage point 1,200 miles away.