Mount St. Helens, The Sleeping Monster
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Here you can find the brief history of Mount St. Helens, and the devastating events that came before and after its eruption. For more geological information or resources, there are links at the bottom of this page.
BACKROUND INFORMATION
Found fifty miles north of Portland, Oregon, is a 40,000-year-old volcano, which last discharged its ash and lava in 1980. Nearby there is a tranquil lake, secluded by flourishing green forests, in Gifford Pinchot National Forest. This monster of a volcano is the colossal Mount Saint Helens. Before 1980, standing 9,677 feet tall, Mount St. Helens was a commanding, symmetrical, snow-capped mountain that dominated the skyline. However, the events that took place during the May 18, 1980 eruption made it the worst volcanic eruption ever in the United States. It significantly changed its stunning surroundings for numerous years to come.
Until 1841, the Klickitat tribe that resided near Mount St. Helens only documented eruptions of it orally. For most of its 40,000 years, it is thought to have been a squat, irregular assortment of volcanic domes. A steep sided mass of doughy lava extruded from a volcanic vent, which was circular in plane view, and had a spiny, rounded, or flat on top. This was often rocky because of fragmentation of cooler, outer crust during the growth of the dome. Beginning about 25,000 years ago, large eruptions created the well-known cinder cone seen today. When explorers first started arriving in the United States, Captain George Vancouver, a British explorer, named Mount St. Helens in honor of his Britannic Majesty?s Ambassador at the court in Madrid, (referring to Baron St. Helens, a British Ambassador to Spain from 1790-1794). One of the early settlers in the region wrote home about an eruption that occurred in 1831. Another brutal eruption occurred in 1842, throwing ashes as far as Dallas. An eyewitness, John L. Parrish, reported ??vast columns of lurid smoke and fire? which, after attaining a certain elevation, spread out in a line parallel to the? horizon, and presented the appearance of a vast table, supported by immense pillars of convolving flame and smoke.? Eruptions continued for fifteen years, and in 1854 The Portland Oregonian reported smoke and ashes continually rising from it, and in 1857 yet another eruption occurred. When this plethora of activity halted, the gargantuan Mount St. Helens became dormant, and stayed that way until May 18, 1980.
One of the numerous things that made this volcano and its eruption bizarre is that Mount St. Helens had a great deal of activity before it officially erupted. The first sign of trouble after its dormant period was on March 20, 1980, at 3:48 pm. A seismograph needle started to quaver at the United States Geological Survey (USGS) University of Washington headquarters. It indicated a substantial earthquake centered twenty miles north of Mount St. Helens. (On the Richter scale, a 3.5 would probably cause slight, localized damage; this trembling was a 4.1). In fifteen to twenty minutes scientists concluded the earthquake had been at Mount St. Helens. They studied the volcano and took geothermal heat readings. By March 25, forty earthquakes per hour were recorded.
THE ERUPTION
On the afternoon of March 27, the mountain exploded, sending ash and steam four miles into the air. Then, a blemish appeared on a snow-capped peak of the volcano- a black crater two hundred and fifty feet wide and sixty feet deep. The USGS sent a team of scientists and officials, and evacuated the area. That night pulverized rock and steam was sent four miles high yet again, the second time that day. By midday March 28 a second crater emerged. Eruptions continued to enlarge both craters until a single crater was created, that was two thousand feet long and five hundred feet deep. On March 30, a friatic eruption occurred. This is when heat rises from the magma, or liquid rock, deep within the volcano, and melts the icy cap so that a steam explosion occurs. That same day six more eruptions occurred, with the earthquakes ranging from 3.3 to 4.4 on the Richter scale. Shortly after, Governor Dixie Lee Ray announced a state of emergency. Roads were closed and the National Guard was called in to hold back sightseers. Steam and ash continued to puff throughout April. Then, on the north side of the summit, the volcano started budging at a rate of five feet per day, which is a great deal compared to the normal rate of one inch per year. On April 10, residents and workers were allowed to return home after signing a release, which stated they knew the risks and accepted responsibility for their own safety. That same day Mount St. Helens erupted sending steam and ash fifteen thousand, five hundred feet above sea level. By this time the bulge was three hundred and twenty feet high. Scientist, after studying the volcano, reported gleaming molten rock was stirring within the crater. On April 30, the bulge was reported as the most serious potential hazard posed by current volcanic activity. The bulge continued to grow. An eight hundred foot ice avalanche slid three thousand feet on May 12, and some forty earthquakes occurred days later. Soon Ray gave the public forty-eight hours to move their belongings out of the area. Then, at 8:32 am on May 18, David Johnston broadcasting, shouted "Vancouver! Vancouver!...This is it..." These were his final words.
Ten seconds past 8:32 on May 18, Mount St. Helens exploded. An earthquake transpired that was a 5.1 on the Richter scale. Earthquakes were the first significant activity near Mount St. Helens since a 90-minute harmonic tremor throbbed through the mountain Tuesday afternoon. The north side of the volcano (the side with the bulge) clasped, slipped down, and turned black in seconds, sixty three thousand feet in the air. The blast was heard two hundred miles away. It was estimated to be five hundred times greater than the twenty-kiloton atomic bomb that destroyed Hiroshima. ?Glowing Avalanches?, or núees ardentes, ran through the forests, and were twelve miles wide and five miles long. The cloud of steam and ash was shot twenty kilometers into the air and its dust traveled around the world. Trees were blown down twenty-five kilometers away and windows were rattled one hundred and sixty kilometers away. Hurricane like winds two hundred miles per hour also took down trees that were two hundred years old. All surviving animals were left in a state of shock. Ash went forty eight thousand feet above the mountain. Lightning caused by the eruptions caused forest fires, but the heavy ash fall put most of them out. Rocks, dirt, and debris, combined with melting snow, ice blocks, and water formed volcanic mudflows that traveled eighty miles per hour and were two hundred and eleven degrees Fahrenheit. They entered the Toutle River and caused thirty-three feet high waves that traveled twelve miles, washing out logging camps, bridges, and houses. Hot ash and gas formed pyrolastic flows traveling one hundred miles per hour and were eight hundred degrees Fahrenheit. They were superheated rivers of mud that flipped one hundred ton trucks and destroyed a train. This superheated flow made the Toutle River ninety degrees Fahrenheit, killing all fish. Helicopters rescued one hundred and fifty people, and more than one thousand were evacuated. It was estimated that one cubic mile of debris was thrown, which equals one ton for every person on earth. It fell from the sky six tenths of an inch thick five hundred miles away. By May 19, one thousand three hundred feet of the volcano?s peak was missing. Trees had been destroyed twenty miles away, and Spirit Lake was underneath 40 feet of boiling mud. The eruption caused Mount St. Helens to go from nine thousand, six hundred seventy seven feet in height to eight thousand, four hundred feet. The biggest landslide ever recorded came when the bulge burst. Most of what emerged was boiling.
AFTERMATH
Afterwards, the Army, Air Force, and National Guard moved in. A unified radio frequency was set up. All pilot?s maps were obsolete because the mountain had changed. There was no reliable list of people in the danger area. At the time seventy (estimated) were buried, suffocated by gases, or burned. The most common caused of death was asphyxiation by ash. Two people died in a car going seventy miles per hour trying to outrun the ash. In many areas the ash was two to three inches thick, and some was even six. The 3M company generously sent its entire stock of one million surgical masks to Washington. Soon everyone had masks, bandanas, coffee filters, or socks over his/her nose or mouth. A sign was put up in a bank, which read: "For security purposes, please remove mask before entering." The real worry was from volcanic ash. The amount of ash was so great it could cover one square mile of Manhattan to a depth of three times the height of the Empire State building. People were afraid the ash would cause cancer, human mutations, silicosis, or aggravate allergies. But, by September, the Batelle Laboratory indicated the ash would not harm the lungs of humans or do damage to individual cells. But, scientists worried about long-term effects on the climate. It could cause freezing, crop killing temperatures in summer, along with horrific blizzards. On May 25 and June 12 major eruptions occurred. On June 18 scientists predicted immediate eruptions, based on some frequency readings. Then on July 22, the dome was blown to bits at the start of a two-hour eruption. Many more violent eruptions happened for the next one to two years, causing avalanches and throwing miles into the air.
Throughout all the complex eruptions of Mount St. Helens, millions of animals and people were destroyed. Thirty-five individuals lost their lives, and twenty-five people were missing and presumed dead. Sixty seven thousand, fifty-two animals died from the initial eruption and lava flows, and one million, four hundred eighty three thousand, nine hundred died as a result of ash fall. Crop loss was estimated at one hundred million dollars, or seven percent of the national crop value for that region. Fifty percent of the alfalfa hay crop was ruined. On the other hand, the wheat, potato, and apple crop was above normal, due to decrease in destructive insect populations. One hundred million dollars worth of timber was destroyed, and three billion, two hundred thousand dollars board feet was salvage. Mudflows destroyed houses, logging camps, and other developments. The mighty Columbia River was closed to freighter traffic for several days as the debris was dredged out. However, wildlife was the greatest loss. Birds and insects burned up or suffocated by ash fall. Mud and rocks cascaded down streams killing everything in them. Superheated gas with ash and pulverized rock hurtled down the face of Mount St. Helens into Spirit Lake killing more water animals. One million, five hundred thousand game birds were lost as a result of eruptions and ash fall. These numbers do not include the eleven million salmon and other fish killed, along with the untold non-game animals, amphibians, and insects.
All in all, the 1980 eruption(s) of Mount St. Helens destroyed and ruined many different, but connected, things. The volcano erupted furiously with many different events, making a mess and also making a need for a lot of people to work many hours to make the surrounding area livable again. Now the volcano known as Mount St. Helens sits silent, waiting. When the day comes that it does erupt again, hopefully we will be prepared enough to cope better with its destructive nature.
~Plate Tectonics and Continental Drift
~Volcano World
~Excellent Pictures Associated w/ Mt St Helens
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