Scientists: 'Supervolcano' possibly brewing under Mount St. Helens

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by By NWCN.com and PAT DOORIS / KGW

NWCN.com

Posted on May 14, 2010 at 10:00 AM

Updated Friday, May 14 at 10:00 AM

Video: Mount St. Helens a 'supervolcano' ?

MOUNT ST. HELENS, Wash. - Mount St. Helens could blow its top again - and the eruption could be bigger and more powerful than its 1980 eruption, say New Zealand scientists. But local scientists aren't quite convinced.

In a new article published in , a team of scientists from GNS Science, an earth and nuclear science institute in Wellington, New Zealand, say they have found evidence a "supervolcano" may be sitting under the mountain. Mount St. Helens has been steaming and spewing ash since its eruption on May 18, 1980.

The New Zealand scientists were able to use conductivity studies that suggest a huge pool of partially molten rock or water under the mountain and what appears to be a column leading deep from under Mount St. Helens to that pool. That molten rock pool is so big, it stretches from Mount St. Helens to Mount Rainier to Mount Adams.

A portion of the article reads:

If the structure beneath the three volcanoes is indeed a vast bubble of partially molten rock, it would be comparable in size to the biggest magma chambers ever discovered, such as the one below Yellowstone National Park.

The New Zealand scientists aren't saying for sure it is a supervolcano, but if it is, it could fuel an enormous eruption in the future.

Every few hundred thousand years, such chambers can erupt as so-called supervolcanoes - the Yellowstone one did so about 640,000 years ago. These enormous eruptions can spew enough sunlight-blocking ash into the atmosphere to cool the climate by several degrees Celsius.

"A really big, big eruption is possible if it is one of those big systems like Yellowstone," Graham Hill, who led the New Zealand study. "I don't think it will be tomorrow, but I couldn't try to predict when it would happen."

Local scientists, however, are a bit more skeptical.

"The conductivity is related to the volcanism. That is certainly true," said Gary Egbert, PhD, a magnetotellurics specialist with Oregon State University and not a member of the New Zealand team, "Whether finding high conductivity in this area is evidence that there's really something unusual here is the thing that is more questionable."

Egbert said part of the conductivity is probably just water.

A spokesperson for the US Geological Survey, which monitors Mount St. Helens, says the supervolcano theory is quite a stretch.

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