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Mount St. Helen
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Mount St. Helen Mount St. Helen is a volcano located along the Cascade range which is a volcano chain stretching from Northern California to British Colombia. It now stands at a height of 8,364 feet above sea level. Mount St. Helen was on of the smaller eruptions of five major ones in Washington State. It’s elevation before the eruption was 9,677 feet high. On March 29, 1980 after a period of one-hundred and twenty-three years of inactivity a earthquake under the volcano quaked, and seven days later a pheartic (steam) explosions began. As magma pushed up from beneath the earth’s surface, the north side of the mountain developed a bulge. Angle and slope-distance measurements indicating that the bulge was growing at a rate of 1.5 feet per day (Lyn Topinka Page 2). By May 17 the volcano’s north-side had been pushed upward and outward 450 feet (Lynn Topinka Page 2). On May 18,1980 at 8:32 a.m. Pacific daylight time a magnitude 5.1 earthquake shook Mount St. Helen. The bulge on the North side of the mountain gave way in a gigantic rock slide releasing pressure and triggering a major rock and pumice eruption . At thirteen hundred feet the peak collapsed and as a result 24 square miles of the valley was filled with rock and debris. From that rock slide 250 square miles of timber, recreation and private lands were demolished from the lateral blast. For more than nine hours the volcano spit vigorous ash in a large plume. Eventually the plume reac...
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