Earthquakes recorded near Alaska volcano dormant 800 years

ANCHORAGE, Alaska — Lots of of small earthquakes have been reported close to a volcano in southeast Alaska believed to have been dormant for no less than 800 years.

The reason for the quakes below Mount Edgecumbe, a volcano close to Sitka that resembles Mount Fuji in Japan, usually are not recognized. Nonetheless, they will not be a sign of volcanic exercise, stated Dave Schneider, a analysis geophysicist with the U.S. Geological Survey on the Alaska Volcano Observatory in Anchorage.

Mount Edgecumbe is a 3,200-foot (976-meter) stratovolcano positioned on Kruzof Island, about 15 miles (24 kilometers) west of Sitka. The volcano is a component of a bigger underwater volcanic subject of lava domes and craters.

The quakes are considerably uncommon since temblors within the space are often tectonic, not volcanic, he stated.

“These aren’t essentially associated to volcanic exercise, they might be a tectonic in nature or a mixture of tectonics and the volcano,” he stated. “We actually can’t inform the distinction at this level.”

Proper now, there is no such thing as a want for an enormous quantity of concern, Schneider stated.

“Volcanoes do have swarms of earthquakes that don’t result in eruption,” he stated.

The earthquakes, most of which had been too small to be noticed on a number of seismic stations, continued Wednesday though the frequency has declined.

“I don’t suppose anyone was even conscious that these occurred,” stated Zach Mayville who answered the cellphone at Home of Liquor in Sitka.

He stated there’s been no injury from the quakes.

“We didn’t really feel something,” Mayville stated. “We’ve heard nothing from anyone, so we’re all good.”

The volcano observatory did a retrospective evaluation of earthquake information close to Mount Edgecumbe, which confirmed a small variety of earthquakes began occurring in 2020.

There’s been about 40 quakes that had been positioned within the space within the final two years, about one or two a month, far lower than what’s been recorded this week.

“You’d anticipate many, many earthquakes to be noticed previous to any eruptive exercise if it had been to happen,” Schneider stated. “Earthquake exercise is our greatest indicator of what’s occurring there, and that’s one thing that we’ll be watching intently.”

Alaska has about 90 volcanoes which have been lively within the final 10,000 years, he stated. Most are distant and never often close to a inhabitants heart like Sitka, which has about 8,500 residents.

There’s no written document of Mount Edgecumbe erupting, however he stated there may be Tlingit oral historical past about small eruptions about 800 years in the past.

The final Mount Edgecumbe eruption preserved within the geologic document was about 4,500 years in the past.

There’s additionally proof of a big eruption 13,000 to 14,500 years in the past the place as much as 3 ft (1 meter) of ash was deposited on what’s now Sitka, whereas 98 ft (30 meters) fell on Kruzof Island.