Volcano may puff away for weeks, even years

By Hal Bernton and Ian Ith
Seattle Times staff reporters

BRUCE ELY / THE OREGONIAN Mount St. Helens exhales another cloud of steam and ash yesterday, its third explosion in less than a week. This aerial photo was taken over Mount St. Helens National Monument.

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But the most likely scenarios don't include a major blow-up that would endanger people or homes, they stressed.

The latest explosion began yesterday at 9:03 a.m., with a few white puffs from the crater morphing into larger, darker clouds that rose some 13,000 feet. The clouds drifted to the northeast, and the ash that dropped from them looked from a distance like rain falling from a thunderhead.

A light dusting of ash was reported in Randle and Packwood in eastern Lewis County, 40 miles or so from the volcano. State emergency-management officials said there was no reason for concern, and that the ash didn't affect daily life in the small timber towns.

"It's a light coating, enough so when you drive it blows up off the highway," said Jeanette Blankenship at the Woodland Motel, 10 miles east of Randle. "But this is nothing like 1980."

Aviation wasn't significantly affected by the emissions yesterday. But the Federal Aviation Administration expanded a no-fly zone that had been limited to the area directly above the volcano. It now includes the area within a five-mile radius of the mountain.

	TROY WAYRYNEN / THE COLUMBIAN Mount St. Helens during yesterday's explosion, as seen looking north with Mount Rainier in the background.

That was primarily to make sure the skies are clear around the volcano in case emergency flights need to get in, said Julie Stewart of the U.S. Department of Agriculture, which manages the land around St. Helens. Media and scientific flights still are permitted, she said.

Yesterday's explosion helped in a rapid resculpting of the inner crater, which as of yesterday had three new vent holes. A section of the crater floor about the size of a hundred football fields has lifted up by an estimated 150 feet.

The deformed area has a new nickname: "The Loaf."

Yesterday's explosion, which lasted about an hour, unfolded right on cue for the encampment of journalists now spread across the parking lot at this viewpoint across Highway 504. Many turned immediately to U.S. Geological Survey scientist Jon Major for analysis.

Major found the initial plume "pretty lazy. It's not building up too rapidly."

The eruption did manage at least temporarily to reduce pressure in the crater. Seismic activity dropped off for a few hours before starting to build again. Yesterday afternoon, scientists said the tremors remained steady but did not have the intensity of the mild earthquakes of late last week.

Instead of ranking about magnitude 3, as they did then, the quakes yesterday were coming in at about 2, a tenfold decrease.

Yesterday's closures at Mount St. Helens • Johnston Ridge Observatory • Ape Cave, near Cougar, south of the mountain • Mount Margaret backcountry north of Spirit Lake • Climbing above 4,800 feet • Sections of the Loowit and Truman trails and the Willow trail on the north side of the volcano • Forest Road 81 between Kalama Horse Camp and Cougar Snow Park • Trailheads north of forest roads 81 and 83 Highway 504 is closed at the Coldwater Ridge Visitor Center intersection to the Johnston Ridge Observatory. Coldwater Ridge Visitor Center is open.

The volcano is likely to put on a lot more such shows in the future. Scientists note that the mountain went through six years of activity between 1980 and 1986.

"People are going to have to get used to seeing vulcanism," said Jake Lowenstern, a U.S. Geological Survey vulcanologist.

Though it was much punier than the May 18, 1980, blast that killed 57 people, yesterday's explosion was the largest and longest since the mountain began to stir last month. Scientists say yesterday's release resulted from water vaporized by heat from magma deep underground, which may reach temperatures of more than 1,000 degrees Celsius.

U.S. Geological Survey scientists say there is an 80 percent chance the fresh magma eventually will work its way to the surface.

They are unsure whether the gas it contains eventually will trigger a substantial eruption or simply ooze out more quietly. They also are unsure of the magma's depth or quantity. But the increasing deformities of "The Loaf," which includes parts of a crater glacier and the edge of a 920-foot-high lava dome, indicate that the pool of magma is expanding and exerting considerable pressure.

Yesterday, however, scientists said the "most likely scenario" is for the volcano to continue in a long, steady pattern of small-scale ash and steam emissions as the magma works up to the surface and then simply gushes out in pools onto the crater floor.

At a briefing in Vancouver, Wash., geologists appeared slightly exasperated by continued assertions that a "main event," as one reporter called it, is just around the corner.

"There's not necessarily going to be a 'big one,' " Lowenstern said. "People have to get that out of their minds."

The scientists' priority for now is tracking the scope of the crater "uplift."

As of yesterday, three Global Positioning System (GPS) monitoring instruments had been placed in the crater. The deployment was a tricky maneuver: A helicopter hovered low above the crater, then lowered the delicate equipment on a cable.

The GPS equipment will become even more important if cloud cover prevents visual observation of the uplift, the scientists said.

Yesterday afternoon, the early-autumn sunshine faded, but the mountain was still visible, its shoulders streaked with fresh gray ash. Dust swirled in the crater. But rain clouds appeared to be drifting up the Toutle River Valley.

That would be bad news for news people who have been fortunate to have mostly clear views of the volcano.

A pair of artists from Southern California said they were ready to put up with some rain. Yesterday, as soon as they had set up canvases to paint the mountain, they instantly became darlings of the news people, who were looking for something to shoot between the volcano clouds.

One of the artists was a shaggy-haired man who calls himself "O." He paints with gallon buckets of acrylic paint that he splashes on a 4- by-5-foot canvas with the aid of paintbrushes lashed to walking sticks. Since arriving late Saturday, he had finished more than a dozen paintings of the mountain and promised more.

"This is a birthing process, the birth of the Earth, and that's my highest truth," he said.

Hal Bernton: 206-464-2581 or hbernton@seattletimes.com; Ian Ith: 206-464-2109 or iith@seattletimes.com

Copyright © 2004 The Seattle Times Company

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