Small to moderate eruption likely at Mount St. Helens

Wash. volcano expected to blow in next few days

September 30, 2004|By Tomas Alex Tizon | Tomas Alex Tizon,LOS ANGELES TIMES

SEATTLE - Mount St. Helens, the volatile mountain that blew its top in spectacular fashion 24 years ago, has been grumbling again, and scientists said yesterday that a small to moderate eruption was possible in the next few days.

Such an event could spew rock and ash thousands of feet in the air, but the fallout likely would not go beyond the volcano's crater or flanks. At worst, scientists say, some debris could travel three miles - nowhere near the closest towns of Cougar and Toutle.

Seismologists monitoring the volcano, which is about 120 miles south of here, yesterday raised the alert level to "volcano advisory" - level 2 on a 3-step scale - after a series of small earthquakes indicated the mountain was, in the words of local seismologist Seth Moran, "ramping up."

Moran said a hardened dome of lava inside the crater also appeared to be growing, which meant that gases or molten rock could be building just below the surface. The lava dome, now about 900 feet tall, grew inside the crater in the years after the May 18, 1980, eruption that killed 57 people and razed 150 square miles of forest.

The eruption blew off the top 1,300 feet of the mountain and caused one of the largest recorded landslides in history. Ash from the explosion eventually circled the globe.

That type of eruption "is not in the cards this time," said Steve Malone, a seismologist at the University of Washington. But, Malone and the other scientists added, predicting volcanic eruptions is not an exact science; it's possible the eruption could be bigger than expected, or it may not happen at all.

"We're not guaranteeing an eruption," said Cynthia Gardner, a research geologist for the Cascades Volcano Observatory in Vancouver, Wash. The observatory is operated by the U.S. Geological Survey.

The U.S. Forest Service has closed hiking trails near the crater and above the 4,800-foot level of the mountain, which measures 8,364 feet. The Weyerhaeuser Corp., which owns 435,000 acres surrounding the mountain, closed off areas within a 12-mile radius of the volcano.

Since 1980, Mount St. Helens has experienced three minor - and largely ignored - explosions. A larger one occurred in 1986. Scientists say the volcano's current build-up resembles the one in 1986.

The Los Angeles Times is a Tribune Publishing newspaper.

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