Scientists: Receding glaciers could lead to volcanic eruptions

April 21, 2010

Chris Waythomas, a vulcanologist with the USGS, says Alaska's volcanoes have a thinner sheet of ice than those in Iceland. (Eric Sowl/KTUU-DT)

by Rhonda McBride
Tuesday, April 20, 2010

ANCHORAGE, Alaska -- The debate over the connection between climate change and volcanic activity is not new.

But the latest eruption of Eyjafjallajökull Volcano in Iceland has some scientists taking a closer look.

"One of the things that captivates your attention when you go to a place like Iceland are its magnificent glaciers. They sit on volcanoes, so it's a natural connection to think about how glaciers and volcanoes interact," said Chris Waythomas, a vulcanologist with the U.S. Geological Survey.

Carolina Pagli, a researcher at the University of Leeds in the United Kingdom, speculates on her website that when ice fields on top of a volcano melt, pressure on the earth's crust shifts, which makes it easier for magma to rise to the surface.

Pagli says Alaskan volcanoes are vulnerable to climate change, especially in the Aleutians.

"It may explain activity at some volcanoes, but probably isn't going to explain it at every one," said Waythomas, who had heard Pagli's theory before the most recent eruption.

Alaska does have many volcanoes with ice on them: Mount Redoubt and Mount Spurr are just two, but Alaska researchers believe that their layers of ice are much thinner than in Iceland.

"Even if you lost all of it, it really wouldn't have much of an effect on the magma chambers," Waythomas said.

Still, it's a theory he says shouldn't be completely discounted.

Most of Alaska's volcanoes have not been studied as much as those in Iceland.

"A lot of the work that's necessary to understand these things hasn't been done yet. A lot of these things in the Aleutians have not been studied in great detail," Waythomas said.

There has been one study at Pavlof Volcano on the Alaska Peninsula to look at the connection between climate and volcanic eruptions.

The study was conducted by Steve McNutt, a researcher at the University of Alaska Fairbanks.

"Pavlov is the most frequently active volcano in North America outside of Hawaii. It commonly erupts in the fall. Now that's a time when there are big storms out of the North Pacific," Waythomas explained.

The theory is that a combination of high tides and storms puts pressure on the earth's crust and provokes volcanic activity.

But other than that, there's little evidence to suggest that global warming is heating up Alaska's volcanoes.

"It's certainly an interesting and plausible theory, but I think at this point, it's still just a theory," Waythomas said.

Researchers at Leeds University say the rate of ice melt and magma production in Iceland has steadily increased over the last century.

Scientists in Alaska are concerned about increased hazards during volcanic eruptions, because as ice fields melt there is more erosion, which could make mud flows a more serious problem during an eruption.

Lake Chakachamna, which is held by a glacier on its west side, could be a problem. Scientists worry that if the glacier thins and retreats, there's nothing to hold the lake back.

Contact Rhonda McBride at rmcbride@ktuu.com

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