Posted by: magmatist | February 24, 2011

More on the Vancouver Sun article

Turns out you can’t read the Vancouver Sun’s misleading article about Baker without a subscription. I have added the text to the end of the previous post, as well as at the bottom of this temporary post.

I communicated with Mark Jellinek, the UBC professor who’s work is the focus of the report. He says he’s the victim of journalistic ‘artistic license’ and has been ‘dealing with it all day’. His paper in Science does not mention Mount Baker, by the way.

DT

Here’s the article.

24 Feb 2011 The Vancouver Sun

BY MARGARET MUNRO

Mount Baker eruption overdue: expert

Researchers are confident they can predict time of next burst

Cloaked in snow and visible across the U. S. border from Vancouver, Mount Baker looks like a gentle giant.

But volcanologist Mark Jellinek, at the University of British Columbia, says Mount Baker, located in Washington state, is probably overdue for an eruption — an explosion he and his colleagues hope to predict well in advance based on the how much “ wagging” goes on inside the volcano as magma rises up from the deep.

According to their research, to be published Thursday in the journal Nature, volcanoes shake and vibrate in distinct and predictable ways when they are going to blow because giant columns of magma “ wag” back and forth inside them.

“ It’s basically like a dog wagging its tail,” says Jellinek, except that the magma columns are up to a kilometre high.

They are so powerful they shake mountains and when they blow they can hurl hot ash up to 40 kilometres into the atmosphere, with sometimes devastating impact as the ash spreads across surrounding areas. ( Vancouver is far enough from Mount Baker it will be spared the worst effect, though Jellinek says he expects the city could be covered in a thick layer of fine ash. “ It would make a huge mess,” he says.)

It has long been known that volcanoes vibrate at pretty much the same frequency before they explode, whether they are in B. C., Alaska, the Caribbean or the Philippines. But until now no one has been able to explain why volcanoes that are so different in size and character behave in the same way.

“ Magma wagging” is the most plausible explanation yet, and may help forecast deadly eruptions, say Jellinek and David Bercovici from Yale University and co-author of the new study.

Their model of the “ magma wagging” explains why tremors in nearly all explosive volcanoes stay in a narrow band of frequencies that can be felt but are so high humans can’t hear them. Just before and during eruptions, the frequency climbs to a higher pitch, and the range spreads out.

It provides “ a fundamental mechanism for tremor that is generic to nearly all volcanically explosive systems,” the researchers report.

As Bercovici put it, the shaking is both a warning “ and a vital clue about what is going on in the belly of the beast.”

There can be weeks to months of warning before volcanoes erupt but some come to life quickly. “ The most recent eruption in the Aleutians in Alaska had five hours notice,” says Jellinek. “ But in general we do better than that.”

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