In this photo provided by the Alaska Volcano Observatory/U.S. Geological Survey is the Tanaga Volcano near Adak, Alaska, on May 23, 2021. A swarm of earthquakes occurring over the past few weeks has intensified at a remote Alaska volcano dormant for over a century, a possible indication of an impending eruption. The Alaska Volcano Observatory raised the alert level to advisory status for Tanaga Volcano late Tuesday, March 7, 2023, after the quakes became very vigorous. (Matt Loewen/Alaska Volcano Observatory/U.S. Geological Survey via AP)

In this photo provided by the Alaska Volcano Observatory/U.S. Geological Survey is the Tanaga Volcano near Adak, Alaska, on May 23, 2021. A swarm of earthquakes occurring over the past few weeks has intensified at a remote Alaska volcano dormant for over a century, a possible indication of an impending eruption. The Alaska Volcano Observatory raised the alert level to advisory status for Tanaga Volcano late Tuesday, March 7, 2023, after the quakes became very vigorous. (Matt Loewen/Alaska Volcano Observatory/U.S. Geological Survey via AP)

Swarm of quakes at Alaska volcano could mean eruption coming

The Alaska Volcano Observatory raised the alert level to advisory status for Tanaga Volcano late Tuesday

By Mark Thiessen

Associated Press

ANCHORAGE — A swarm of earthquakes occurring over the past few weeks has intensified at a remote Alaska volcano dormant for over a century, a possible indication of an impending eruption.

The Alaska Volcano Observatory raised the alert level to advisory status for Tanaga Volcano late Tuesday after the quakes became very vigorous.

“We started seeing a whole lot of earthquakes occurring, one after the other, several per minute,” said John Power, a research geophysicist with the U.S. Geological Survey stationed in Anchorage at the Alaska Volcano Observatory.

ADVERTISEMENT
0 seconds of 0 secondsVolume 0%
Press shift question mark to access a list of keyboard shortcuts
00:00
00:00
00:00
 

There have been hundreds of small earthquakes, none larger than magnitude 2.75, but they are concentrated beneath the summit of the volcano, he said.

“That indicates that we’re seeing significant unrest at the volcano,” Power said.

“Whether or not this will lead to an eruption is something we can’t say at this point in time,” he said. “But we are concerned about it enough that we have gone and elevated the warning level.”

While the increase causes concern, he said many times earthquake activity will drop off with no eruption.

“It’s anybody’s guess as to where this particular round of earthquake activity may end up,” he said.

The volcano is on an uninhabited island in the western Aleutians, about 1,250 miles southwest of Anchorage. There are no communities or structures there, but Adak, a city of about 170 residents on another island, is about 65 miles away and could see ashfall.

If the volcano were to erupt, the biggest threat would be to aircraft. The Aleutians are below the routes that jets fly between North America and Asia. Volcanic ash is angular and sharp and can cause an airplane engine to shut down. Previous eruptions had both ash clouds and viscous lava that moves very slowly away from the mountain, much like what happened at Mount St. Helens in Washington state in 1980.

“It’s very different than what you would see, for example, in Hawaii, Kilauea or Mauna Loa, where you see these beautiful red rivers of lava flowing down the side of the volcano,” Power said.

Tanaga is actually part of a three-volcano complex on the island. It’s the tallest of the three at 5,925 feet. It sits in the middle, with Sajaka, a 4,443-foot volcano to its west. Sajaka had an older cone that collapsed into the North Pacific Ocean with a new cone that has emerged.

To the east of Tanaga is Takawangha, a 4,754-foot volcano that is mostly ice-covered except for four craters, the Alaska Volcano Observatory says.

The last known eruption for Tanaga was in 1914. It erupted twice in the late 1700s and again in 1829.

The observatory in a release said there are no known eruptions of Takawangha or Sajaka. However, field work has indicated that eruptions may have occurred from those volcanos and were attributed to Tanaga.

More in News

University of Alaska President Pat Pitney speaks during a meeting of the UA Board of Regents at Kenai Peninsula College in Soldotna, Alaska, on Feb. 22, 2025. (Jake Dye/Peninsula Clarion)
Pitney: UA, KPC seeing momentum, attendance growth

The university president described KPC as “a leader of the pack” in enrollment growth at the university

University of Alaska Board of Regents Chair Ralph Seekins speaks during a meeting at Kenai Peninsula College in Soldotna, Alaska, on Feb. 22, 2025. (Jake Dye/Peninsula Clarion)
‘Where does this end?’: University of Alaska to strip diversity and inclusivity language from programs, policies

The board was clear during the meeting that they were responding to pressure from the federal government.

U.S. Rep. Nick Begich holds a telephone town hall on Monday, Feb. 17, 2025. (Screenshot from the Facebook page of U.S. Rep. Nick Begich)
Murkowski, Begich host telephone town halls to address constituent concerns

Both events were inaccessible to some, who grew frustrated at technical problems

Rep. Will Stapp, R-Fairbanks, speaks on the House floor on Thursday, May 2, 2024. (Photo by James Brooks/Alaska Beacon)
Education funding bill unexpectedly advances again, nears House floor vote amid affordability concerns

HB 69 clears Finance Committee at first hearing as minority says discussions there are not worthwhile.

The front of the Kenai Police Department as seen on Dec. 10, 2019. (Photo by Brian Mazurek/Peninsula Clarion)
Kenai accepts federal grant for police vests

The funds entirely cover the purchase of three ballistic vests this fiscal year.

Soldotna High School student Ethan Anding asks a question during a Kenai Peninsula Borough School District budget development meeting at Kenai Central High School in Kenai, Alaska, on Wednesday, Feb. 19, 2025. (Jake Dye/Peninsula Clarion)
District discusses $17M deficit at community meeting

More than 100 people gathered in the KCHS auditorium.

Alaska State Troopers logo.
Man found dead near Kasilof roadway on Tuesday

He was found off Pollard Loop Road near Reindeer Lane in the Kasilof area.

Fire Marshal Jeremy Hamilton gives a tour to students during Job Shadow Day at Kenai Fire Department in Kenai, Alaska, on Wednesday, Feb. 19, 2025. (Roddy Craig/Peninsula Clarion)
Kenai students try on careers for Job Shadow Day

Roughly 100 students from Kenai Central High School scattered to more than 30 businesses to get a feel for the workforce.

A 2015 Ford Explorer that was stolen from the Kenai Chamber of Commerce before crashing into a tree near Wells Fargo Bank is loaded onto a tow truck in Kenai, Alaska, on Tuesday, Feb. 18, 2025. (Jake Dye/Peninsula Clarion)
Car stolen, crashed in Kenai

The car was reportedly taken from the Kenai Chamber of Commerce and Visitor Center.

Most Read