Snowy Volcanic Peaks Could Blow Covers Like Mt. St. Helens : Cascades: Lassen, Shasta and Mammoth are among the main candidates. Eruption in 1987 helped provide clues to origins of life.

By TIM KLASS

May 14, 1995 12 AM PT

ASSOCIATED PRESS

Some mountains rise above the rest, snowcapped sentinels of a seemingly timeless majesty. From Northern California to southwestern British Columbia, looming over lush forests to the west and arid lands to the east, they are landmarks by which to take one’s bearings.

To American Indians, volcanoes embodied supernaturally powerful spirits against which no mortal could prevail.

On Aug. 16, 1987, when New Age believers around the world celebrated a planetary alignment in a “harmonic convergence,” the biggest gathering--more than 5,000 people--was at Mt. Shasta.

When Mt. Rainier appears like a scoop of ice cream floating over the south end of Lake Washington, people in Seattle typically say, “The mountain is out,” meaning the sky is clear and all’s right with the world.

Someday, that paragon of reassurance will explode.

Rainier, Shasta and other major peaks in the Cascade Range are volcanoes. Even after centuries in repose, they can produce blowouts that rank at the top of nature’s most terrifying spectacles.

“Volcanoes that don’t erupt frequently can be the most dangerous,” said Daniel Dzurisin, scientist in charge of the U.S. Geological Survey Cascades Volcano Observatory in Vancouver, Wash. “They don’t erupt very often, but when they do, they erupt violently.”

It was 15 years ago that Mt. St. Helens, the youngest and most active volcano in the Cascades, provided a 24-megaton reminder of those hellfire forces and their power to reshape our world.

That eruption left 57 people dead, devastated 230 square miles, and blanketed areas more than 300 miles to the east with volcanic ash.

Since then, the USGS has developed a computerized volcano-monitoring system and worldwide crisis-response team. Within the Mt. St. Helens National Volcanic Monument, an obliterated forest ecosystem is being reborn and hot springs may yield clues to the origins of life.

The big bang’s biggest legacy, however, is better understanding of volcanoes as part of the history, culture, economy and development of the American West.

“Certainly the eruption of St. Helens raised people’s consciousness several-fold,” Dzurisin said.

Even with clouds filling the crater, as is typical about two-thirds of the time, visitors on a recent windy, rainy day were moved by the devastation around the Coldwater Ridge Visitor Center.

“You don’t think about the possibility that geographical features can disappear,” said John D. Reagh, 47, a Lake Stevens, Wash., lawyer who brought his family. “For mountains to lose their tops and lakes to be buried, that’s something.”

Almost all the volcanoes between Alaska and Mexico lie along the Cascades, from the Garibaldi volcanic belt in British Columbia to Lassen Peak in California, and between Mono Lake and Bishop in eastern California, especially around Mammoth Lakes.

Their mineral-rich volcanic ash is found in soil as far east as Nebraska. Their eruptions, landslides and mudflows have turned barren, uninhabitable canyons and gorges into fertile farmlands and town sites.

About 25 volcanoes, all extinct, lie beneath the streets, homes, parks, businesses and factories of Portland, Ore., and its suburbs.

In prehistoric times, Native Americans hundreds of miles away traded food and furs for arrowheads and knives made of obsidian from Newberry Caldera in central Oregon. For eight months in 1872-73, 160 Modoc Indians held off more than 1,000 U.S. Cavalry troops in the basaltic maze that is now Lava Beds National Monument in far northern California.

Runoff from volcanic snowfields and glaciers maintains stream flows for drinking water, irrigation, fish and wildlife. The 26 glaciers on Rainier, highest peak in the Cascades at 14,410 feet, contain as much water as the reservoir behind Grand Coulee Dam.

Mt. Bachelor in Oregon and Mammoth Mountain in California are destination ski resorts. Millions of people a year visit national parks at Rainier; Crater Lake, which formed in the shell left by a cataclysmic eruption of Mt. Mazama about 7,500 years ago in southern Oregon, and Lassen, the last to erupt in the 48 contiguous states before St. Helens.

Lassen’s activity in 1914-21 peaked on May 22, 1915, when an explosion sent a mushroom-shaped ash cloud 5 to 7 miles above the 10,457-foot summit. Four miles away, trees 6 feet in diameter were snapped off at the stump and hurled hundreds of feet. A hundred miles to the east, ashfall was so thick that trains had to slow down.

A lesser eruption of Glass Mountain, part of the Medicine Lake volcano northeast of Shasta, occurred in 1910.

St. Helens erupted periodically from 1800 to 1857. Also active in the late 18th and 19th centuries were Rainier, Shasta, Mt. Hood in northern Oregon, Mt. Baker in northern Washington state and Glacier Peak in central Washington.

“The eruptions they had in the 19th Century were really very small,” said Robert L. Christiansen, Dzurisin’s predecessor at the observatory.

A peak so lovely that it was known as the Mt. Fuji of America, St. Helens was silent for 123 years until March 27, 1980, when a steam burst after a series of small earthquakes opened a new crater near the summit.

More than 10,000 tremors were recorded at the 9,677-foot mountain in the next 7 1/2 weeks as the north flank bulged with an upwelling of magma, or molten rock. Outbursts of rock and dust darkened once-pristine glaciers.

At 8:32 a.m. on May 18, 1980, loosened by a 5.1-magnitude quake, the upper north flank collapsed, allowing gas-laden magma to explode outward and upward like uncorked champagne.

From a monitoring post 5 1/2 miles to the north, USGS scientist David A. Johnston radioed, “Vancouver, Vancouver. This is it!”

Those were his last words.

Nearly three-fourths of a cubic mile of rock, mud, ice, snow and water surged northward across the Spirit Lake basin, over the ridge where Johnston was perched and then westward 17 miles down the north fork of the Toutle River--the largest landslide witnessed by humans in recorded history.

Moving as fast as 600 m.p.h., the lateral blast leveled 150,000 acres of forest. As far as 19 miles away, 150-year-old fir trees were shattered and the billowing dust and gas registered 572 degrees.

That afternoon, a 12-foot wall of mud, debris and water from melted glaciers tore down the Toutle. So much silt reached the Columbia River that the shipping channel to Portland was closed.

An ash cloud rose to 16 miles and circled the globe. Traces of the gritty dust were found as far as northwestern Minnesota.

In place of the once-symmetrical peak sat a gaping, horseshoe-shaped crater rimmed by jagged walls that rose to 8,365 feet.

Johnston and 56 others died, along with 5,000 deer, 1,500 elk, 200 bears and millions of fish, birds and other creatures. Property losses included hundreds of miles of roads, 27 bridges, 17 miles of railroad, 221 homes and 4.7 billion board feet of timber--enough to build 300,000 two-bedroom houses.

Contrary to statements by then-President Jimmy Carter and the late Washington Gov. Dixy Lee Ray, evidence in a later court case showed none of those who died--mostly weekend campers and Weyerhaeuser Co. contract workers--were in a restricted zone illegally.

St. Helens erupted six more times that year, spreading ash from Aberdeen on the Washington coast to Portland and The Dalles, Ore. Over the next six years, a blocky, oblong lava dome grew to about 920 feet--1 1/2 times as high as the Seattle Space Needle but still a couple hundred feet below the crater rim--and about 2,840 by 885 feet at the base. Since 1986, activity has been limited to a few steam bursts.

Today, anglers fish for rainbow trout in Coldwater Lake, formed by the landslide and eruption, and 550 or more elk range along the north fork of the Toutle.

In Pumice Plain below the crater, virtually devoid of life in mid-1980, at least 30 plant species have returned. Farther out in the blast zone, some naturally seeded trees are 3 to 4 feet high.

“There’s a tremendous amount of trial and error going on,” said monument scientist Peter Frenzen. “Millions and millions of seeds are coming in--blown in, walked in, various ways--and only a few are going to sprout and take root.”

In hot springs formed after the eruption, University of Washington oceanographer John A. Baross and other scientists found primitive cells called archaeobacteria in 190-degree water.

The same type of organism was found previously in long-established hot springs in the ocean and, on land, in Iceland and at Yellowstone National Park. The discovery at St. Helens supports the theory that archaeobacteria, believed to date back as far as 4 billion years, may live below the Earth’s crust.

“It is clear that these high-temperature archaea are the most ancient organisms extant on Earth today,” Baross said.

Scientists theorize that some archaeobacteria mutated to survive in cooler water, eventually evolving into more advanced cells.

Recent research “very strongly indicates that most of the higher organisms, including humans, evolved from a thermophyte,” or high-temperature archaeobacteria, Baross said.

To Frenzen, the blast zone offers a glimpse at more recent periods, the aftermaths of previous eruptions in the Pacific Northwest, and each stage of recovery teaches new lessons on the evolution of the region’s ecosystem.

In about a century the area will have the appearance of a young forest, and it will take another century for a mature forest to emerge, he estimated.

Of course, that’s without further volcanic outbursts.

St. Helens far exceeded what Lassen did 65 years earlier, but U.S. volcanoes have exploded with greater force in recent geological history and at least half a dozen--including St. Helens--could do so again.

“The eruption was, in global terms, comparatively small,” wrote Catherine J. Hickson, head of the Cordilleran Division of the Geological Survey of Canada in Vancouver, British Columbia.

A 20- by 15-mile caldera at Mammoth Lakes was formed about 700,000 years ago by the eruption of 140 cubic miles of magma--560 times as much as from St. Helens. Ash covered a 580-square-mile area from central California to southwest Nevada and can be found in soil as far away as central Nebraska.

Dzurisin and Christiansen, now based at the USGS regional office in Menlo Park, Calif., rate St. Helens and Mammoth Lakes as the most likely to go ballistic within the foreseeable future.

St. Helens “is likely to erupt again within a few decades or a century at the most,” Christiansen said.

Other Cascade volcanoes at the top of the eruption watch list, barely a notch below St. Helens, are Rainier, Hood, Lassen, Shasta and Baker.

“We consider the hazard potential of Rainier to be the greatest simply because of its setting,” Christiansen said.

Research into the likelihood of future eruptions and potential hazards in the United States is the primary mission of the 65 people at the Vancouver observatory, established when St. Helens became active in 1980.

They install and maintain monitoring devices, study eruption deposits and produce hazard maps showing specific risks at various locations.

Using software developed in Menlo Park, Calif., observatory scientists can quickly assemble and install state-of-the-art systems using personal computers to analyze data from devices that automatically report earthquakes, mudflows and deformation anywhere an eruption may be brewing.

The computers can be programmed to sound an alarm, even call a scientist’s pager, at any preset level or pattern of activity.

Under the Volcano Disaster Assistance Program, funded half by the State Department and half by USGS, teams have been dispatched to install these portable observatories in Colombia, Ecuador, Guatemala, New Guinea, the Philippines and Mexico.

Once equipment is installed, it stays, said Andrew B. Lockhart, one of five scientists in the program.

“If we go there, it’s because they have a problem, and they’re going to continue to have a problem, so what good is it going to do to take this stuff and then bring it back?” he said. “We tell them, ‘Here you are. This is yours. Do good science and let us know anything you learn.’ ”

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Peaks and Perils

A brief rundown on some of the biggest peaks and volcanic areas from south to north, with elevations in feet, and eruption likelihood:

1 -- Most likely in the near future;

2 -- Likely, but may be a longer wait;

3 -- Less likely and possibly extinct;

4 -- Probably extinct.

Mono Lake, Inyo Craters, Mammoth Mountain

Elevation: Mammoth Mountain, 11,053 feet

Eruption likelihood: 1+

Last activity: Apparently 1751-1830 at Mono Lake, 1400-1500 at Inyo Craters

Location: Eastern California, east of Yosemite National Park; Lee Vining to Mammoth Lakes; 140 miles south of Reno, Nev.

Lassen Peak

Elevation: 10,457 feet

Eruption likelihood: 1

Last activity: 1914-1921

Location: Northern California, 50 miles east of Redding

Mt. Shasta

Elevation: 14,162 feet

Eruption likelihood: 1

Last activity: Probably 1786

Location: Northern California, east of Weed and Mt. Shasta City

Crater Lake

Elevation: Mt. Scott (high point on the rim) 8,938 feet, lake level, 6,176 feet

Eruption likelihood: 2-

Last activity: About 4100 BC.

Location: Southern Oregon, 60 miles north of Klamath Falls and 75 miles northeast of Medford

Mt. Jefferson, Three Sisters, Paulina Peak

Elevations: Mt. Jefferson, 10,497 feet; North Sister, 10,085 feet; Middle Sister, 10,047 feet; South Sister, 10,358 feet; Paulina Peak (high point in Newberry Caldera), 7,985 feet

Eruption likelihoods: Three Sisters, 2; Newberry, 2; Jefferson, 3-

Last activity: About AD 650 (Belknap Crater).

Location: Central Oregon, 75 miles east of Eugene, Corvallis or Salem, and 45 miles northwest to 30 miles south of Bend

Mt. Hood

Elevation: 11,245 feet

Eruption likelihood: 1

Last activity: 1760-1790, possibly 1859-65

Location: Northern Oregon, 55 miles east of Portland

Mt. Adams

Elevation: 12,276 feet

Eruption likelihood: 3+

Last activity: 1500 BC, possibly earlier