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Monitoring earthquakes underneath the 10,200-foot Redoubt Volcano about 100 miles southwest of Anchorage, scientists from the Alaska Volcano Observatory warned that an eruption was imminent, sending experienced Alaskans shopping for protection against a dusty shower of volcanic ash that could descend on south-central Alaska.
"Every time this happens we do get a run on dust masks and goggles," said Phil Robinson, manager of an Alaska Industrial Hardware store in Anchorage. "That's the two main things for eye and respiratory protection."
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The observatory, a joint program between the U.S. Geological Survey, the University of Alaska Geophysical Institute and the state Division of Geological and Geophysical Surveys, was formed in response to the 1986 eruption of Mount Augustine.
It has a variety of tools to predict eruptions. As magma moves beneath a volcano before an eruption, it often generates earthquakes, swells the surface of a mountain and increases the gases emitted. The observatory samples gases, measures earthquake activity with seismometers and watches for deformities in the landscape.
On Nov. 5, geologists noted changed emissions and minor melting near the Redoubt summit and raised the threat level from green to yellow. It jumped to orange — the stage just before eruption — on Sunday in response to a sharp increase in earthquake activity below the volcano.
Alaska's volcanoes are not like Hawaii's. "Most of them don't put out the red river of lava," said the observatory's John Power.
Instead, they typically explode and shoot ash 30,000 to 50,000 feet high — more than nine miles — into the jet stream.
"It's a very abrasive kind of rock fragment," Power said. "It's not the kind of ash that you find at the base of your wood stove."
The particulate has jagged edges and has been used as an industrial abrasive. "They use this to polish all kinds of metals," he said.
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