Vulkaanuitbarsting Mount St.Helens

Bron: CNN

Scientists watching unusual events near volcano



Series of earthquakes could signal eruption of Mount St. Helens

VANCOUVER, Washington (CNN) -- A series of unusual earthquakes near Mount St. Helens in recent days has scientists warning that something more serious could be imminent.

The "hazardous event" the U.S. Geological Survey warns is possible could be an explosion caused by steam building up inside the volcano, or it could be more serious -- involving molten rock and deadly gas.

The quakes are occurring less than a mile below the surface of an 876-foot-tall lava dome within Mount St. Helens' crater. Some of them are of a type that indicates the presence of pressurized fluids or magma, the USGS and the University of Washington Pacific Northwest Seismograph Network in Seattle said Monday in a joint statement.

"We're still thinking it's not likely to be anything real big," said Tom Pierson, a USGS research scientist at the Cascades Volcano Observatory in Vancouver. "We're not real worried. [The seismic activity is] very interesting to us because it's unusual."

A group of very small, shallow earthquakes, called a "swarm" by seismologists, began Thursday morning and peaked about midday Friday, Pierson said, then slowly declined through Sunday morning. Those quakes were all less than magnitude 1.0.

But since then, more than 10 earthquakes with a magnitude between 2.0 and 2.8 have been recorded, according to the notice issued Monday.

"They're all pretty small magnitude," Pierson said. "Maybe that largest one, you might feel if you were pretty close by."

Still, that's the most earthquakes recorded in a 24-hour period since October 1986, when Mount St. Helens had a minor eruption that added to the lava dome that began forming after the catastrophic eruption of May 18, 1980. That eruption blew out the side of the mountain, killing 57 people and deforesting 230 square miles.

Yet scientists cannot rule out the possibility of a more serious eruption, he said. An aircraft will soon fly over the lava dome to test for the presence of carbon dioxide and sulfur dioxide, signs that magma might be building up.

Similar earthquake swarms were recorded in 1998 and 2001, but no explosion occurred in either year, Pierson said.

The U.S. Forest Service, which manages the park on Mount St. Helens, has closed areas around the crater and the volcano's outer flanks to hikers.

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Info & Geschiedenis
Mount St. Helens is een grote nog actieve vulkaan. Een compositevukaan, ook wel stratovulkaan genoemd. Deze vulkanen zijn typisch stijl aan de zijden, een soort symmetrische kegels. Ook Mount Hood een andere vulkaan dicht bij Portland is een compositievulkaan. Mount Hood is een actieve vulkaan, evenals Mount St. Helens, welke elk moment kan uitbarsten tussen nu en zeshonderd jaar. Als deze vulkaan uitbarst zal heel Portland bedolven worden onder lava en hete as. Ook Mount Rainier vlak naast Mount St. Helens en Mount Fuji in Japan zijn compositievulkanen.

Compositievulkanen hebben over het algemeen een krater. Mount St. Helens had een krater welke werd dichtgemaakt door aardverschuivingen en een Magma staaf die de krater bij wijze van spreken uitdeukte. Mount St. Helens is ook een zogenaamde Subduction-zone vulkaan. Zulke vulkanen zijn explosief omdat het magma te stijf is om makkelijk weg te vloeien. Zo'n vulkaan komt tot ontploffing net als je je hand op een koolzuurhoudend drankje doet, schud en dan snel loslaat.

Louwala-Clough is de indiaanse naam voor Mount St. Helens, wat rokende berg betekent. Volgens een legende was de berg eens een mooie meid, "Loowit" genaamd. Toen twee zonen van de grote geest "Sahale" verliefd op haar werden, kon ze niet kiezen tussen de twee. De twee moedigen, Wyeast and Klickitat vochten om haar, dorpen en bossen begravend in het gevecht. Sahale was razend. Hij gooide de drie geliefden uiteen en een machtige berg rees waar een ieder viel. Omdat Loowit mooi was, was haar berg (Mount St. Helens) ook mooi, symmetrisch steen van verblindend wit. Wyeast (Mount Hood) heft zijn hoofd in trots, maar Klickitat (Mount Adams) huilt omdat hij de mooie meid, omhuld met sneeuw wil zien, daarom buigt hij zijn hoofd terwijl hij in de verte naar St. Helens staart.

Zondag 18 mei 1980.
Wat weer een zonnige rustige dag had moeten worden, veranderd in een catastrofale ramp.

Mount St. Helens in de staat Washington behoort tot de bergketen The Cascades genaamd. Deze strekt zich uit vanaf grens met Canada in de staat Washington tot 1125 km verder in Californie, waar ze aansluiten op de Sierra Nevada bergketen.
In deze bergketen komen vele vulkanen voor welke zo'n 90 miljoen jaar geleden gevormd werden. Een van die vulkanen is Mount St Helens. Mount. St. Helens ligt ongeveer tussen Portland (Oregon) en Seattle (Washington).

Op 18 mei 1980 barstte de 2949 m. hoge Mount St. Helens vulkaan plotseling uit met een kracht van meer dan 500 atoombommen van het formaat waarmee Hirosjima en Nagasagi in augustus 1945 werden verwoest. Deze kracht in ongeveer te vergelijken met 400 miljoen ton TNT (springstof). De bovenste 398 meter werd van de top weggeblazen en liet een spoor van vernielingen achter Steden in de omgeving waren dagen lang bedekt met een dikke laag as. De aswolk steeg meer dat 25 km omhoog de strak blauwe lucht in. Deze aswolk heeft het weer rond de vulkaan zeer beïnvloedt.

Nna 10 jaar is de verwoesting nog steeds waarneembaar, maar toch is de natuur zich al aan het herstellen. Dat is het mooie van de natuur. Ondanks dat er een verwoestende kracht van die zelfde natuur iets vernield achterlaat, weet het toch na jaren weer op te krabbelen. Er leven weer dieren, er begint weer flora te verschijnen. In 1982 is het park een Nationaal Monument geworden. Er zijn namelijk mensen tijdens de uitbarsting vermist geraakt en nooit gevonden.

Een documentaire met een enorme impact, al is het beeld waarschijnlijk lang zo indrukwekkend niet als de werkelijke berg. Deze kun je natuurlijk ook bezoeken. Op discovery channel is lange tijd de Documentaire gedraaid en het filmpje van de daadwerkelijk explosie van de berg is dan ook indrukwekkend.

Foto van de berg VOOR de eruptie:


Foto van de berg NA de eruptie


Meer informatie over Mount St.Helens op ---> http://www.fs.fed.us/gpnf/mshnvm/
en ook een interessante Nederlandse link ---> http://www.verenigdestatenvanamerika.com/reisverhalen/wj01.html

quote:

Op dinsdag 28 september 2004 13:37 schreef -CRASH- het volgende:
M.ST.Helens was zeker indrukwekkend
maar vergleken met Krakatoa... een "kleintje"

On the 26th August 1883,
Krakatoa, off Java, exploded, destroying the island.
The explosion was heard in Australia, 4,800 km away,
while the dust cloud circled the Earth,
causing the Moon to turn 'blue' in Britain.

[afbeelding]

Klopt inderdaad... dat was een nog veel zwaardere explosie/uitbarsting
maar toen was er nog niet echt nieuwsberichten over de wereld, zoals TV etc...
1980 wat dat betreft staat meer in het geheugen gegrift.

Update van Dinsdag

Quakes Still Rippling Across Mount St. Helens
Tuesday, September 28, 2004

SEATTLE — Small earthquakes rattled Mount St. Helens at the rate of one or two a minute Monday, and seismologists were working to determine the significance of some of the most intense seismic activity in nearly 20 years.

Early tests of gas samples collected above the volcano by helicopter Monday did not show unusually high levels of carbon dioxide or sulfur.

"This tells us that we are probably not yet seeing magma moving up in the system," said Jeff Wynn, chief scientist with the U.S. Geological Survey (search) in Vancouver, Wash. He noted additional tests are necessary to better define whether there's magma moving under the mountain's crater.

Scientists are trying to figure out what is going on beneath the 925-foot-high dome of hardened lava within the mountain's gaping crater. They want to know whether the quakes are the result of water seeping into the mountain or magma.

In either case, they'll continue to watch the volcano — which erupted to devastating effect in 1980 — from the Cascade Volcano Observatory (search) in Vancouver, about 50 miles away. Additional flights are also planned but not yet scheduled, Wynn said.

A helicopter carried scientists and instruments over the crater Monday to assess the gases and ground deformation that would indicate pressure building below the dome.

Waarschuwing voor uitbarsting Mount St.Helens

Uitgegeven: 30 september 2004 07:18

SEATTLE - Amerikaanse wetenschappers hebben woensdag gewaarschuwd voor de mogelijke uitbarsting van de vulkaan Mount St.Helens in de Amerikaanse staat Washington.

De "kleine tot middelgrote" eruptie zal mogelijk binnen enkele dagen plaatshebben, aldus de geologen. De laatste grote uitbarsting van de vulkaan was in 1980. Toen kwamen 57 mensen om het leven.

Mount St.Helens

VANCOUVER, Washington (CNN) -- The U.S. Geological Survey issued a volcanic advisory Wednesday for Mount St. Helens with officials warning of a heightened possibility of a small to moderate eruption.

There was no immediate timetable for when an eruption could occur.

Geologists at the Cascades Volcano Observatory said the area could remain under the volcanic advisory for days or even weeks.

"We think there is a heightened possibility that we could see an explosion," said Cynthia Gardner, acting scientist in charge at the observatory. "We are expecting that either nothing could happen or perhaps we could have an explosive event."

She said if a small to moderate eruption occurred, rocks could be hurled up to 3 miles from the volcanic dome and ash could spew up to 10,000 feet in the air and be carried about 10 miles downwind.

"The concern there is an ash and aviation hazard," she said, noting that volcanic ash can clog a plane's engine and cause other problems.

The U.S. Forest Service has closed access into the crater and access to areas above 4,800 feet around Mount St. Helens. Trails on the north side of the crater have been closed.

The advisory that was issued is the third of four levels -- with the fourth being eruption.

Hier trouwens een link naar een webcam.. http://www.fs.fed.us/gpnf/volcanocams/msh/

SEATTLE — The flurry of earthquakes at Mount St. Helens (search) intensified further Thursday, and one scientist put the chance of a small eruption happening in the next few days at 70 percent.

Jeff Wynn, chief scientist at the U.S. Geologic Survey's (search) Cascade Volcano Observatory in Vancouver, Wash., said tiny quakes were happening three or four times a minute. Larger quakes, with magnitudes of 3 to 3.3, were happening every three or four minutes, he said.

New measurements show the 975-foot lava dome in the volcano's crater has moved 2 1/2 inches to the north since Monday, Wynn said.

Small Eruptian, Smoke rock Mount St.Helens



VANCOUVER, Washington (CNN) -- Scientists are closely watching Mount St. Helens after a small eruption spewed smoke and ash thousands of feet Friday before another earthquake rattled the volcano.

A series of small earthquakes was detected in the week before the Friday afternoon's eruption. This seismic activity decreased shortly after the noon (3 p.m. ET) eruption, but picked up again within hours.

Peter Frenzen, a scientist with the Mount St. Helens National Volcanic Monument, said a 2.0 magnitude earthquake was detected.

One scientist described the eruption as a "hiccup."

The volcano spewed a harmless plume of steam and ash into the air Friday, the biggest eruption by the volcano in 18 years.

A small explosion was detected on the south side of the volcano's lava dome, where cracks had been detected in a glacier, said John Major of the U.S. Geological Survey.

The mountain then vented a combination of steam and ash for 24 minutes, sending a pale gray column nearly 10,000 feet into the blue Washington sky.

"There is no indication that magma has reached the surface," Major said.

Molten rock is called magma before reaching the surface where it then becomes lava.

Scientists said the presence of magma could indicate the potential for a more serious eruption.

Geologist Tom Pierson said the event "was really a hiccup. [Eruptions] could be a little bigger once real magma is involved."

A visible plume -- which was mostly steam but contained some ash -- moved southwest about six miles, Major said.

The Portland, Oregon, metropolitan area lies about 50 miles southwest of Mount St. Helens.

er staat een filmpje op de website van Fox News genaamd :"there she blows"...
Typisch Amerikaans dat er eerst reclame komt over de presidentsverkiezingen en dan het nieuwsfilmpje over de uitbarsting. ---> http://www.foxnews.com/story/0,2933,134186,00.html

Mount St. Helens ready to Blow: Eruption Imminent

MOUNT ST. HELENS NATIONAL MONUMENT, Wash. — Mount St. Helens stewed in volcanic gases and low-level earthquakes Sunday, with crowds of eager tourists hoping to glimpse an eruption that scientists said could happen immediately or take a few weeks.

A second long tremor early Sunday and an increase in volcanic gases strongly suggest magma is moving inside, researchers from the U.S. Geological Survey said. The mountain's alert was raised to Level 3, the highest possible, after a volcanic tremor was detected Saturday for the first time since before the mountain's 1980 eruption.

I don't think anyone now thinks this will stop with steam explosions," geologist Willie Scott said Sunday at the Geological Survey's Cascades Volcano Observatory in Vancouver, Wash., about 50 miles south.

But Scott said scientists discussed lowering their alert from a Level 3 "volcano advisory," which indicates eruption is imminent, to Level 2 "volcanic unrest," which indicates an eruption is possible. They needed more data before making any change, he said.

"What we haven't gotten back today yet is a lot of field measurements — there's a gas flight going on, a flight to use thermal imaging to look at the [lava] dome, GPS data needs to be downloaded," Scott said Sunday. "There's a lot of work that needs to be done. That will occur overnight and tomorrow morning."

Mount St. Helens Belches Steam Anew

MOUNT ST. HELENS NATIONAL MONUMENT, Wash. — Mount St. Helens (search) blew off more steam Monday, shooting a billowing white plume several hundred feet above the volcano and thrilling hundreds of visitors who had gathered below the rumbling mountain.

"Wow. It was amazing," said 9-year-old Alex Turchiano, who watched from a nearby visitors center. "I was hoping to see lava so I could see the trees fall down and the lava flow into the water. I wanted to see what it was going to do — whether it would stop or keep going."

Scientists, who continued to warn that the volcano could blow at any moment, stopped short of calling the steam burst an actual eruption, saying no volcanic material apparently was emitted. The steam quickly dissipated and did not threaten any structures near Mount St. Helens.

Even if a larger eruption comes, officials say there was little or no chance of a repeat of the mountain's lethal 1980 explosion, or Hawaiian-style lava flows. The eruption 24 years ago blew 1,300 feet off the top of the peak, killed 57 people and coated much of the Pacific Northwest with ash.

Since Sept. 23, thousands of tiny earthquakes have shaken the mountain and several steam eruptions have occurred, the most seismic activity at the peak since the months following the 1980 blast. A burst of ash and steam on Friday was followed Saturday by a smaller plume of steam and a volcanic tremor. A smaller extended volcanic vibration was detected Sunday.

Another Steam Eruption at St. Helens

MOUNT ST. HELENS NATIONAL MONUMENT, Wash. — Mount St. Helens exhaled a spectacular roiling cloud of steam and ash Tuesday, sprinkling grit on a small town some 25 miles away.

The volcano has been venting steam and small amounts of ash daily since Friday, but Tuesday morning's burst was the largest, producing a billowing, dark gray cloud that rose thousands of feet above the 8,364-foot-high rim of the crater and streamed to the northeast.

For days, scientists have been warning that the volcano could blow at any moment with enough force to endanger lives and property. But geologists said Tuesday a more likely scenario was weeks or months of smaller-scale venting, with the possibility lava could enlarge the dome within the mountain's gaping crater.

Steam drifts away from Mount St. Helens after an emission Tuesday.

MOUNT ST. HELENS NATIONAL MONUMENT, Washington (AP) -- Mount St. Helens blew off a spectacular cloud of steam and ash on Tuesday, the biggest plume yet in days of rumblings and the latest indication that a larger eruption may be in the works.

Tuesday's burst sent a dark gray cloud thousands of feet above the mountain before it streamed several miles to the northeast.

U.S. Geological Survey vulcanologist Jake Lowenstern said the plume had "a significant amount of ash in it" as it rose rapidly above the 8,364-foot rim of the mountain.

Interessante Websites Sassie, thx
Heb Mount Helens zelf een aantal jaren geleden in het echt gezien toen ik in NW USA was. Indrukwekkend landschap. Denk inderdaad dat een superuitbarsting meer met zich mee brengt in negatieve vorm dan 'leuke plaatjes'

Renewed Steam at St.Helens on Sunday

MOUNT ST. HELENS, Wash. — Mount St. Helens vented a new column of steam Sunday, a lazy plume that rose out of the crater of the snow-dusted volcano.

The billow of steam rose from an area where a large upwelling or bulge of rock has been growing on the dome-shaped formation of rock in the crater. The plume rose several hundred feet above the 8,364-foot volcano , and light wind slowly blew it toward the south and southeast.

The venting reminded scientists of the volcano's activity 20 years ago, when it built the dome following its catastrophic 1980 eruption.

"It's a view very, very reminiscent of the years in the 1980s during dome-building and a few years after when the system was hot and water was being heated and vapor was rising and steam clouds were forming," said Willie Scott, a geologist with the U.S. Geological Survey
=================================
Jammer dat de foto onduidelijk is

er was gisteren nog wel een docu op National Geographic op over uitbarstingen van de Stromboli.. Best wel interessant. Van die onderzoekers die op de flanken een kamp op slaan en dan dag en nacht de "wacht" houden om mooie plaatjes te schieten.

Lava breaks surface at Mount St. Helens

SEATTLE (AP) — After weeks of earthquakes and steam eruptions, Mount St. Helens has a new lava dome that could even eclipse the volcano's old one.
The quakes subsided as the new lava emerged Monday and cooled in the open air, suggesting molten rock from deep inside the Earth had found the path of least resistance by going around the old dome, said Jon Major, a hydrologist with the U.S. Geological Survey.

Unlike the dramatic rivers of red-hot lava from Hawaii's volcano, St. Helens' extrusion of new rock was subtle and difficult to see from outside the crater. A lazy plume of steam rose slowly from the mountain for much of Tuesday.

Infrared instruments recorded a surface temperature of nearly 1,100 degrees Fahrenheit, confirming that the second dome consisted of cooling lava rather than old rock which had been pushed upward, said USGS volcanologist Willie Scott.

"The fact that we see stuff at the surface that hot means it's new rock," Scott said.

The last dome-building activity at St. Helens began in the months after its deadly May 1980 eruption and lasted six years. Layers of emerging rock gradually formed a rocky dome nearly 1,000 feet tall at the center of the crater floor. The top of the new dome is almost level with the old one just to the north.

"It's possible this new feature will enlarge and perhaps even dwarf the old dome," said Tina Neal, a USGS geologist.

The mountain had been shaking since Sept. 23, with periods of sharp jolts — up to magnitude 3.3 — occurring as often as four times a minute at the height of seismic activity.

"The inference was that those were breaking a pathway" through rock, Major said.

Explosive eruptions are still possible and often follow lava extrusion, said John Pallister, a volcanologist with the USGS.

The 1980 eruption left 57 people dead, leveled trees for miles around and covered much of the Pacific Northwest with ash. It was "barely a five" on the eight-level Volcanic Explosive Index, Major said.

At this point, scientists believe there is a 10% chance of a level four or larger eruption at the 8,364-foot mountain, he said. The area immediately around the mountain is closed.

Monitoring the gases emitted by lava from Mount St. Helens might provide clues to future eruptions, a British volcano expert reported Thursday.

The isotope content of these gases might indicate whether the next eruption will be a catastrophic blast, as occurred in 1980, according to a paper by Jon Blundy of Bristol University, published in Thursday's issue of the journal Science.

Blundy and doctoral student Kim Berlo studied the gases from magma in the mountain's 1980 eruption and concluded there were two lava reservoirs.

One, located a little more than four miles deep had been shedding gas for five years before that explosive eruption, they said, and a second short-lived reservoir was located nearly two-and-a-half miles deep.

Blundy reported that the magma which erupted in May 1980 came from both the deep and shallow reservoirs. Later, more gentle eruptions, came exclusively from magma trapped at shallow levels.

Mount St. Helens has been rumbling in recent weeks, producing a new lava dome in the crater. Scientists are watching to see if a more substantial eruption will occur.

"We have shown there is a link between the storage depth of magma and the explosiveness of an eruption," Blundy said in a statement.

"This suggests that monitoring the abundance of short-lived radioactive isotopes above restless volcanoes could be a useful tool for predicting the style of the next eruption. It might also provide clues as to when the next eruption will occur," he reported.

New Mount St. Helens lava dome grows

VANCOUVER, Washington (CNN) -- A new lava dome inside Mount St. Helens' crater has sprouted a growth that extends upward nearly 330 feet, U.S. Geological Survey officials said Saturday.

The exposed rock face, with a temperature between 752 and 952 degrees Fahrenheit, casts a red glow that can be seen from the north on clear nights, survey geologist Willie Scott said. Temperatures have spiked at nearly 1,300 degrees.

"It's hot enough to glow, but it's solid," Scott said. "It's not like Hawaii lava. It looks like solid rock ... It's formed this welt, and now it's punched through."

The elongated lava dome spreads southward from the old dome, which was created in the six years after the volcano's cataclysmic eruption of May 18, 1980. Like the old dome, it is made of a volcanic rock called dacite, officials said. The growth has taken place since October 27.

The volcano has been rumbling and spewing steam since late September. Geologists say that activity points to an explosive eruption, though none believe it would reach the intensity of the 1980 eruption that killed 57 people and knocked more than 1,000 feet off the top of the mountain. That eruption also created the current crater.

Molten rock first reached the surface October 11.

CNN) -- Washington state's Mount St. Helens volcano belched a column of smoke and ash nearly six miles high Tuesday evening, leaving a plume visible for more than 50 miles, authorities reported.

Glowing lava was visible inside the mountain's crater after the disturbance, which occurred at about 5:20 p.m. (8:20 p.m. ET). There were no immediate reports of damage or injuries, said Alan Steele, an official with Washington's Emergency Management Division.

Pilots reported the column reached an altitude of about 30,000 feet, the National Weather Service said, but no flights were reported canceled or delayed.

The Weather Service posted ash-fall warnings for the Cascade Mountain foothills of southern Washington after the plume appeared.

"The area that the plume is supposed to go through is pretty much forest land," said Sgt. Tony Barnes of the Clark County, Washington, sheriff's department.

Most of the ash was expected to fall in uninhabited areas of neighboring Skamania County.

"We're concerned that it, of course, has erupted, but it's not to the point where we've mobilized resources up into that area," Skamania County Undersheriff Dave Cox said.

The volcano, located about 45 miles northeast of Vancouver, Washington, has been rumbling and spewing steam since late September.

Geologists say that activity points to an explosive eruption, though none believe it will reach the intensity of the 1980 eruption that killed 57 people and knocked more than 1,000 feet off the top of the mountain.

Monidique

Is dat een recente foto? Damn..die is wel erg 'mooi' en indrukwekkend...

tis vandaag precies 25 jaar geleden dat St.Helens explodeerde

http://vulcan.wr.usgs.gov/Volcanoes/MSH/

Mount St.Helens - 25 Years After the BigBang


MOUNT ST. HELENS NATIONAL MONUMENT, Washington (AP) -- A small Douglas fir breaks up from the ground six miles from the base of Mount St. Helens. In the distance, trees scattered like dropped matchsticks lie in the place they were toppled by a cloud of fragmented rock and ash that exploded from this mountain 25 years ago.

The devastating eruption killed 57 people and an overwhelming amount of plant and animal life. But the barren landscape is now scattered with green, and diverse wildlife has made a home in a vastly different habitat.

As the force of the blast destroyed all in its path, it also carried within it new life -- seedlings carried from the south side landed and began to grow. Seeds continue to arrive via animals returning to the area.

Pine trees, honeysuckle and firs are all growing in the blast zone, without the help of man. Alder, cottonwood and willows also abound in an area once covered with ash and debris.

"There was nothing out here. It's easy to forget it was like that," said Peter Frenzen, monument scientist for the U.S. Forest Service at Mount St. Helens. "The next forest is essentially here. We just have to wait for it all to grow up."

The stunning mountain with the horseshoe-shaped crater in its side rumbled back to life September 23, with shuddering seismic activity that peaked above magnitude 3 as hot magma broke through rocks in its path. Molten rock reached the surface October 11, marking resumption of dome-building activity that had stopped in 1986.

On March 8, it shot ash higher than 30,000 feet, but since then has maintained low-key activity, with wispy smoke regularly floating from the crater. (Full story)

Scientists have said a more explosive eruption is possible at any time. But the threat level has decreased enough to allow visitors back to the Johnston Ridge Observatory five miles from the crater. The observatory, named for a scientist killed in the 1980 blast, reopened May 6 for the first time since October.

"This whole mountain is a research tool," said Jeri Botsford, 54, a volunteer who will tell the story of the mountain to many of the 250,000 people expected to come to Johnston Ridge this summer.



18th May 1980

Mount Rainier - Similar St.Helens event posing a threat



ORTING, Washington (AP) -- In the shadow of Mount Rainier, people go about their lives -- going to shop, going to school, going to work.

One day, though, the routine will be broken by a rumble that sounds like a thousand freight trains. If all works accordingly, sirens will alert the 4,400 residents that they have less than 45 minutes to evacuate -- or be buried by an avalanche of mud and debris tumbling off the flank of the 14,411-foot volcano.

Scientists know Mount Rainier could erupt as Mount St. Helens did in 1980. It could gradually build up and explode, or part of it may collapse. It could happen in 200 years, or it could happen tonight.

"People get burned by these kind of events because they think it can't happen in their lifetime," said Willie Scott of the U.S. Geological Survey.

The agency ranks Mount Rainier as the third most dangerous volcano in the nation, after Kilauea on Hawaii's Big Island and Mount St. Helens. Both are currently active.

Other studies call Rainier the most dangerous volcano in the world -- not just for its explosive potential, but because of the 3 million people who live in the Seattle-Tacoma-Bellevue metropolitan area. At least 100,000 people live on top of Rainier mudflows that have solidified.

Mudflow poses a serious threat for Orting. Two rivers drain off the mountain, hug the town and converge just beyond it, putting Orting squarely in the mountain's strike zone. The town, in fact, was built atop a 500-year-old mudflow that buried the valley 30 feet deep.

Construction crews working on new housing developments for Orting's growing population have dug up massive tree stumps -- remnants of a forest buried there the last time Mount Rainier rumbled.

Yet, the risks did not worry Dawn So when she moved here two years ago. She was just looking for a good place to raise her children and open a quilting store.

"I wanted to have my kids in a better school district, a smaller town," she said. "I like to let them play in the front yard without having to worry about them."

Her family has planned its escape routes, and she's confident they could get to high ground in time. She does not, however, spend much time thinking about Rainier's threat.

"It's such a highly improbable situation," she said. "Disasters can happen wherever you're at."

The risk of catastrophe every couple thousand years has not stopped brisk development, either. But as scientists identified Rainier as a threat in the decades after Mount St. Helens' eruption, government officials and citizens have begun preparing.

Most of the mudflows -- also called lahars -- from Mount Rainier were triggered by an eruption, Scott said. But the most recent, the Electron mudflow that buried Orting 500 years ago, did not seem to follow that pattern.