No End Seems to Be in Sight

Until a cap is formed, Mount St. Helens may continue rumbling

When Mount St. Helens finally blew its top after almost two months of rumbling and sputtering, the show was spectacular enough that it hardly required an encore for a century or so. But last week the seemingly inexhaustible volcano gave another lively performance. A second major eruption shook the mountain over the Memorial Day weekend, and steam and ash belched forth in fitful bursts throughout the week. More ominously, seismologists detected tremors originating from deep within the volcano's molten rock core, another sign of restlessness.

To add to the jitters of beleaguered residents, two moderate earthquakes suddenly jolted Mount Margaret, a peak only 13 km (eight miles) northeast of Mount St. Helens. Though scientists emphasized that these seismic disturbances were not hints of an impending eruption, the tremors only added to what might be called a case of tectonic fever on the West Coast. Hundreds of small earthquakes shook the Sierra Nevada in central California, causing landslides and some injuries. At least 100 of the quakes measured above 4.0 on the Richter scale and three reached 6.0 or higher, levels at which there would have been more widespread destruction in populated areas.

None of this earth activity appeared directly related to Mount St. Helens. And, indeed, by midweek Tim Hait, the U.S. Geological Survey's chief spokesman at the scene, was describing Mount St. Helens as "in a relaxed state of mind." But none of the U.S.G.S. scientists would say how long the calm would last. After Mount St. Helens rose from its slumber in 1831, it erupted 14 times in the next 25 years. Says Hait: "This time it could go on for five years, ten years or 20 years. That's a heck of an answer but there's no way of telling."

The latest round of activity caught scientists by surprise. Though volcanologists have been able to predict almost to the hour when the volcanoes of the Hawaiian Islands will erupt, Mount St. Helens presents a more difficult problem for would-be prognosticators. The molten rock, or magma, underneath the Washington volcano is a thicker, silica-rich material (unlike the less viscous molten basalt of the Hawaiian chain); more pressure must build up before the hot gases trapped within it are released. Thus the mountain erupts infrequently and violently.

No one can tell for sure how soon the mountain will clear itself of these pent-up gases, but U.S.G.S. scientists were saying last week that they would not be surprised if Mount St. Helens continued venting steam, ash and pumice intermittently for another ten or 15 years. The reason, the scientists explained, is that it could take that long for the volcano to complete the internal rebuilding process that will seal it off again.

According to their scenario, some of the molten rock from the subterranean cauldron of magma under the mountain will slowly be forced upward, like toothpaste being squeezed out of a tube. It will push through the vents in the "plug" of debris within the volcano's throat and emerge as lava. When it is finally exposed to the air, the lava will harden rapidly; it will probably not have enough volume or velocity to overflow the volcano's rim. Instead, as it solidifies, it will likely form a dome or cap over the vents. Eventually the dome should become massive enough to plug up the volcano like a cork in a bottle. But the corking process may be interrupted by repeated explosions, as pressure builds up underneath and ruptures the newly formed dome. Admits U.S.G.S. Volcanologist Charles Zablocki: "We are going to school on this one.

The mountain was also providing painful lessons for those who live near it. The prevailing westerly winds suddenly reversed themselves and dropped ash over a huge area from Tacoma, Wash., to Eugene, Ore. including many communities that had so far largely escaped the sooty downpour. Along the coast, thousands of Memorial Day tourists were stranded by the poor visibility and impossible road conditions. In Portland which likes to call itself the "most livable city," the International Airport was forced to suspend operations, while a Pacific Coast League baseball game was "ashed out." Residents donned surgical and industrial face masks, if they could find any, and there was arun on pantyhose to protect auto carburetors. When a light drizzle began turning the ash into a pasty goo, even street sweepers and water hoses seemed to be of little help. In Washington's agricultural Cowlitz County, the ash found its way into electrical transformers, causing short circuits and blackouts. In nearby Toledo, Wash., farmers feared that continued power outages would disrupt milking and leave chick en coops unheated during cold nights.

The mountain has already left 22 dead and 55 missing, including Harry Truman, the feisty octogenarian who remained behind at his lodge near Spirit Lake, in the volcano's shadow. It was also taking a psychological toll. The renewed ashfall, along with the danger of fresh flooding and mudslides, forced an exodus of residents from the nearby towns of Cougar, Ariel and Amboy to makeshift refugee camps. It was their second evacuation, and the volcano's continuing assaults were beginning to fray tempers. Said Otis Bouchard, a gas station operator in Castlerock: "I'll tell you one thing. I'm getting damn tired of this mountain." Tom Nelson, a supervisor at a devastated timber camp, echoed that frustration with an understandable, if implausible suggestion: "Why don't they just take a couple of jets and bomb the mountain?"

With the latest eruption, the estimated loss to crops, timber and property rose to nearly $1.5 billion. The cost of the cleanup is staggering. Mud dumped into the Cowlitz and Columbia rivers must be dredged out. Roads and bridges will have to be rebuilt and sewage and drain systems unplugged. In Washington State alone, 370,000 people have been left temporarily jobless. Perhaps one-tenth may be out of work for a year. A still incalculable long-term effect may be a rash of respiratory and lung ailments from continued inhalation of the ash.

But statistics alone do not give a full sense of the volcano's fury. Bob Carpenter, a Portland auto mechanic, described the destruction that he saw as he rode by train across the muddy, logjammed Toutle River: "It was eerie, unreal, almost like looking at a graveyard in a London fog, with steam rising among the sheared trees and debris and only the sound of the train on the track." Susan Hobart, a reporter for Portland's Oregonian, added: "The living are not welcome here. The ground rejects you, trying to suck you into foot-deep mud. Chill winds knife into your spine. Ash floats in the air, killing your sense of smell. Every instinct, every emotion warns you to go away. I felt like we were trespassing, like we didn't have nature's permission to visit its ashen graves.''

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