Monday, May 9, 2005; Page A07
By Rick WeissWashington Post Staff Writer
Monday, May 9, 2005; Page A07
An additional 21 volcanoes -- including some in California, Washington and Oregon and the Yellowstone caldera in Wyoming -- pose lesser threats but also deserve better monitoring, the report says, in part because of their proximity to population centers and because many are capped in snowfields that, upon melting, would cause deadly debris flows called lahars.
The new analysis (at http://pubs.usgs.gov/of/2005/1164/ ) could not have been written 25 years ago, when an exploding St. Helens triggered Earth's largest landslide in recorded history. But scientists have since learned much about eruption prediction -- in part by studying the 23 smaller eruptions at St. Helens through 1986 and the current one, which started in October.
One lesson is that a volcano can come very close to erupting without seismic warnings, yet seismic activity can also go on for years without it meaning an eruption is imminent. Thus it pays to deploy many kinds of instruments.
"There's no such thing as an 'eruptometer,' " said Guffanti of USGS's volcano hazards program. "You want these different things that all together can say, 'Oh my god, we're having an eruption!' "
Automated monitors are also crucial because many dangerous volcanoes are out of view and inaccessible for much of the winter.
"We want to be proactive and not have to drop down on a parachute and play catch up," Guffanti said.
For about $15 million, the most hazardous volcanoes could be wired up into a National Volcano Early Warning System, consisting of sensors that feed into the nation's five volcano observatories, according to the USGS.
The system could also help prevent unnecessary and costly evacuations when frightening activity can be found to pose no imminent risk, as turned out to be the case with the 1996 rumblings beneath Akutan in the Aleutian Islands.
"That magma came up so close to the surface of the earth it actually formed ground cracks," Guffanti said. But the agency correctly assured residents that they were safe.
The aviation industry is a prime supporter of a warning system. Tens of thousands of people flying between North America and Asia pass over volcanoes in the Aleutians and Marianas every day. Yet when Anatahan erupted in the Marianas in 2003, five hours went by before airlines were notified.
"It only takes five minutes for that ash to get up to 20,000 feet," said Terry McVenes, a pilot and executive air safety chairman for the Air Line Pilots Association.
Ash particles are hard as metal and have caused hundreds of millions of dollars in damage to aircraft. They abrade windshields so badly, they leave pilots blinded. Their static charges can wipe out navigation systems. Worse, they melt inside hot engines, sticking to fan blades and clogging cooling vents, causing engine shutdowns.
"You can easily drop 10 to 15,000 feet getting everything restarted," McVenes said.
"There's an investment that was made in the science after Mount St. Helens erupted in 1980," Ewert said -- an investment that allowed scientists to issue warnings in advance of last year's eruption and alert air traffic controllers within five minutes of the first ash release.
"Volcanoes always give you some warning," Ewert said. But somebody, he said, has to be listening.
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