Sunday, June 14, 2009

Alaska: Volcano could erupt again!

Since Mt. Redoubt's last explosion in April, it has quietly continued to ooze lava from its vent, creating a massive hardened dome that could blow at any moment and unleash another ashfall on south central Alaska.The volcano's dome, about the size of nine football fields, has formed a precarious plug over its steaming vent, scientists say. That's kept ash from spewing into the atmosphere and has perhaps led many to believe the volcano's rumblings are over.

But if the dome cracks or collapses, as scientists say it likely will, ash could once again blast into the atmosphere and ground airplanes during Alaska's summer tourist season.

A second worry is that a cracked dome, accompanied by another explosion, would allow hot gas and rock to blast down the mountainside, which would melt snow and ice and once again flood the Drift River valley, as it did in late March.

Scientists estimate the amount of lava comprising the hardened dome is so massive it could fill 11 Louisiana Superdomes. It is roughly as thick as a 65-story building.

Alaska lava is not like Hawaii lava or probably what most people picture as lava, said geologist Allison Payne of the Alaska Volcano Observatory. It's not as fluid. It's thick and sticky, she said.

Gravity or the building of pressure beneath the dome could make it collapse, scientists say.

The lava has been building up for two months. The last time the volcano erupted in 1989 and 1990, a similar dome lasted 36 days before it collapsed and unclogged the vent. "Based on Redoubt's past activity, this is pretty unstable," Payne said.

This eruption has shown similar patterns to the one almost two decades ago, which is why scientists eagerly anticipate more rumblings, Payne said.

But when it could blow is anyone's guess. "It could happen in 10 minutes or a month or not at all," she said.

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