This May photo shows Mount Edgecumbe on a relatively clear day. New research has shed new light on magma activity underneath the “historically active” volcano. (Michael S. Lockett / Juneau Empire)

This May photo shows Mount Edgecumbe on a relatively clear day. New research has shed new light on magma activity underneath the “historically active” volcano. (Michael S. Lockett / Juneau Empire)

New research finds magma rising under Mount Edgecumbe

No signs of imminent eruption

Though magma underneath Mount Edgecumbe is on the rise, University of Alaska Fairbanks associate professor of geodesy Ronni Grapenthin said concerns of an eruption are not.

“Mount Edgecumbe isn’t showing signs of an imminent eruption,” Grapenthin said in an email. “The deformation has been constant for more than 3 years now and the magma is pooling at 10 km (about 6.2 miles) depth, that’s still pretty deep. Prior to any eruptive activity we would expect to observe precursors. We now have instruments on the volcano, so we’d be able to detect small earthquakes, or changes in deformation, or we might detect volcanic gases.”

According to an article released by University of Alaska Fairbanks’ Geophysical Institute earlier this month, magma beneath the long-dormant volcano in Southeast Alaska has been steadily moving upward through the Earth’s crust, which was observed by the Alaska Volcano Observatory by using a new method that relies on computer modeling based on satellite imagery and cloud data. The observatory said this new approach could lead to earlier detection of volcanic unrest in Alaska.

Mount Edgecumbe is 15 miles west of Sitka, which has a population of about 8,500 residents, and is located on Kruzof Island on the west side of Sitka Sound. According to the article, it is part of the Mount Edgecumbe Volcanic Field that inhabits the domes and crater of adjacent Crater Ridge.

Grapenthin, who served as the research paper’s lead author, said that while it is not uncommon for volcanoes to deform, the activity at Mount Edgecumbe is unusual because reactivation of dormant volcanic systems is rarely observed.

Most active volcanoes have cycles of activity that are years to decades long,” Grapenthin said. “That doesn’t mean they erupt that often, but they generate earthquakes, deform, emit gases, or have geothermal systems. For Edgecumbe, we know thanks to Tlingit history handed down by Herman Kitka that the last activity was about 800-900 years ago. This was low level eruptive activity rather than a big 1980 Mount St Helens-like explosions if we compare the descriptions to volcanic activity we observe — perhaps something like fire fountaining. While we know a lot about Edgecumbe from past eruptions, we ‘re now learning more about the active volcanic system now.”

[Alaska Science Forum: A porcupine’s winter in slow motion]

In collaboration with the Alaska Volcano Observatory, the Alaska Satellite Facility helped to process data in the cloud, which was said to be a first for the volcano team. Grapenthin said that cloud computing uses remote servers to store data and provide computing services so a researcher can avoid having to download and process data, which typically can take weeks or months.

“We’re using workflows that the Alaska Satellite Facility has developed that allow us to analyze and model the satellite radar data in the cloud — cloud computing,” Grapenthin said. “This means that we don’t have to download 7 years of satellite data and set up workflows on a local server. Instead of taking weeks to months to achieve high quality results, it now takes just a few days. That’s important in hazard settings like volcano monitoring. We need to be able to understand what is going on and be able to make informed decisions and communicate them to the public as soon as possible. Edgecumbe was an excellent example — there were earthquakes, but no instruments on the ground because the volcano was considered inactive. The nearest seismometer was 25 kilometers (about 15.5 miles) away, part of the network to monitor tectonic earthquakes, which are bigger than those at volcanoes. So remote sensing data was the best tool, and within days we were able to make a statement that the observed earthquake activity is part of continuous magma movement that has happened over the last three years. We learned a lot about the current activity of that volcano very quickly.”

Alaska Volcano Observatory’s coordinating scientist at the Geophysical Institute David Fee said they’re applying the new approach to other volcanoes across Alaska, including Trident Volcano, about 30 miles north of Katmai Bay, which according to the article is showing signs of elevated unrest.

“We are now applying these techniques to help monitor other volcanoes across Alaska. This is particularly useful for volcanoes where we have limited ground-based instrumentation, “ Fee said in an email. “I can say that we have sufficient ground-based seismic monitoring at 33 volcanoes in Alaska to consider them ‘monitored.’ This is out of a total of 53 historically active volcanoes in the state. Therefore a little over half of our historically active volcanoes have ground-based monitoring.”

At Mount Edgecumbe, the observatory’s research indicated that magma is rising to about 6 miles from a depth of about 12 miles and has caused earthquakes and significant surface deformation.

The research team began surveying the area after several earthquakes were observed at Mount Edgecumbe on April 11, according to the article. Using satellite radar data, researchers were able to analyze the previous 7 and a half years of ground deformation. Four days after beginning their research, the observatory team determined that an intrusion of new magma in the area was the cause for the sudden cluster of earthquakes. Grapenthin said the earthquakes have since subsided.

“There was a swarm of activity for a few days, releasing stresses in the crust that had built up as the magma below lifts up the ground,” Grapenthin said. “This was the second such swarm. In early 2020 there was a similar one that started with a larger earthquake and then subsided over a few weeks. Before that, we couldn’t find any larger earthquakes going back to 1990.”

Grapenthin said that while an eruption is not imminent, currently there is no evidence of the magma rise slowing down.

“It’s difficult to project into the future, because we’d need to know better what the ground surrounding the magma is made of: is the magma any lighter than the surrounding material, then it might want to rise further — similar to how lava lamps work, if not, it may just stay where it is,” Grapenthin said. “If it would rise further, it’s pooling beneath some stronger rocks — is it strong or weak, that means what stresses can it withstand before the magma would break through – and how far would it rise then? Any further rise would create seismicity and a change in surface uplift, which we can now track. We would expect to see clear signs of change in activity.”

• Contact reporter Jonson Kuhn at

More in News

Jasmine Chavez, a crew member aboard the Quantum of the Seas cruise ship, waves to her family during a cell phone conversation after disembarking from the ship at Marine Park on May 10. (Mark Sabbatini / Juneau Empire file photo)
Ships in port for the week of July 6

Here’s what to expect this week.

Residents of Strasbaugh Apartments on Gastineau Avenue and others in the neighborhood wait outside a sealed-off area Sunday morning after a landslide triggered by heavy rain hit the building. (Mark Sabbatini / Juneau Empire)
Landslide triggered by heavy rain damages apartment building on Gastineau Avenue

Officials close street as multiple mudslides reported; up to 4” more rain forecast by Monday night.

Shelley McNurney (right) and Tami Hesseltine examine a muticolor storage shelf in the gym of the former Floyd Dryden Middle School on Saturday, where surplus items from the school were being sold to residents and given away to nonprofit entities. (Mark Sabbatini / Juneau Empire)
No more pencils, no more bookshelves: Floyd Dryden works to clear out surplus items large and small

Furniture, microscopes, pianos among gymful of items being given away or sold by shut-down school.

Former President Donald Trump is surrounded by Secret Service agents at a campaign rally in Butler, Pa, on Saturday. Trump was rushed off stage at rally after sounds like shots; the former president was escorted into his motorcade at his rally in Butler, Pa., a rural town about an hour north of Pittsburgh. (Doug Mills/The New York Times)
Trump rally shooting investigated as assassination attempt; gunman identified

One rally attendee and the shooter dead, two other spectators critically injured.

Looking like a gray turtle, an automated mower cuts grass in front of Thunder Mountain Middle School with boxes stacked in a classroom window beyond. (Laurie Craig / Juneau Empire)
Random adventures of robo-mowers…now performing again this summer at Juneau’s schools

Four pillow-sized bots resembling turtles with tiny razor-sharp blades provide class for the grass.

Disney Williams (right) orders coffee from Lorelai Bingham from the Flying Squirrel coffee stand at Juneau International Airport on Thursday. (Mark Sabbatini / Juneau Empire)
New coffee stand at airport stirs up heated dispute about having proper authorization to operate

Fans of Flying Squirrel Espresso praise location, hours; officials say FAA violations could be costly.

Nano Brooks and Emily Mesch file for candidacy on Friday at the City and Borough of Juneau Municipal Clerk’s office in City Hall. (Jasz Garrett / Juneau Empire)
City and Borough of Juneau regular municipal election candidate filing period opens

So far, most vie for Assembly District 2 seat — mayor, Board of Education, and District 1 also open.

Killah Priest performs at the Juneau Arts and Culture Center in December 2019. (Photo courtesy of Lance Mitchell)
Killah Priest sets new record with Alaskan artists on ‘Killah Borealis’

Wu-Tang Clan rapper seeks to lift Alaskan voices and culture in his return performance to Juneau

Most Read