New Type of Volcanic Hazard Discovered

New Type of Volcanic Hazard Discovered

By Sara Goudarzi
LiveScience Staff Writer
14 March 2006


Scientists have uncovered a new type of worrisome volcanic eruption after studying images of an odd-shaped ash plume that came unexpectedly crashing down.

Typically, the gentlest part of a volcanic eruption is the gradual falling of ash. But the plummeting plume of an eruption in South America four years ago appeared to cause damage to oil pipelines on the ground that experts would not have expected.

"The usual volcanic plume consists of a stalk capped with an umbrella, and resembles the mushroom of an atom bomb blast," said Susan Kieffer a geology professor at the University of Illinois at Urbana-Champaign. "But the umbrella on this plume was wavy, like the shell of a scallop."

When the Reventador volcano erupted in 2002 near Quito, Ecuador, the flood of ash from the explosion traveled down to valleys several miles away. Moving close to the ground, the outflow heated the air, which rose, carrying the ash up with it.

..snip..

"The initial ash fall died in the formation of the plume, but only to come back with much more punch than before," Kieffer told LiveScience. "Our analysis suggests that the Reventador umbrella collapsed rapidly, forming new and especially dangerous ash flows."...>

http://www.livescience.com/forcesofnature/060314_volcano_ash.html

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I love volcanos... From a large distance.

Fascinating post, Dover.

I understand from the article that umbrella plumes aren't uncommon in themselves. What was different about this one is that the plume didn't spread much. It wasn't super hot and it contained moisture. These factors caused it to fall rapidly.

I'm surprised this kind of plume isn't common. I wonder why it isn't.

of the cooler ash with moisture. When they can determine that, we'll probably know why it's not as common, as well as the odds of occurrence and optimal conditions for this to happen.

I can't wait to see how it shakes out! :hi:

I'd really like to find out.

What you wrote makes sense. They'll need to find out what conditions led to the formation of the moist ash plume.

Volcanoes have interested me for as long as I can remember. It may have started when I was a child living in Japan. Once, while picking blueberries in Mt. Asama's lava field, I watched it erupt. I never forgot it.