Essay on The 1980 Eruption of Mount Saint Helens and Its Impact

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Mount Saint Helens, located in the Pacific Northwest in southwestern Washington, stood approximately 9,500 feet above sea level prior to its eruption in 1980 (Tarbuck, 2012). Part of the Cascade Mountain Range, it is a composite volcano constructed of alternating layers of lava flows, ash, and other volcanic debris with steep, symmetrical sides . It also belongs to the North American segment of the Pacific “Ring of Fire.” This is where the tectonic plate from the Pacific is forced under the North America plate. According to an article in the Associated Press, “this Cascade "subduction zone" also is the area that can produce magnitude-9 earthquakes when the plates slip or break. The magma from this zone makes its way to the surface in …show more content…
St. Helens, 2014) and there was a great chance that there would be a magma eruption. This observable activity stopped briefly in late April and early May. On May 7th, a blasts of steam erupted sporadically over the course of several days. This activity also stopped by May 16th. A large “bulge” on the north face of the mountain had been growing since the initial eruptions. This bulge was made by the magma under the mountain. Over 10,000 quakes were recorded in a small area less than 1.6 miles directly beneath this bulge on the north side of the mountain. (History - Mt. St. Helens, 2014) The constant quakes and magma build up had been wedging the volcano apart, creating instability on the mountainside. On May 18, 1980, a disastrous eruption occurred that would change the face of the mountain and the surrounding areas. The huge bulge suddenly collapsed, as noted by geologists Keith and Dorothy Stoffel, who witnessed the chain of events from a plane at the volcano’s summit. According to their reports, they “noticed land sliding of rock and ice debris inward into the crater…the south-facing wall of the north side of the main crater was especially active. Within a matter of seconds, perhaps 15 seconds, the whole north side of the summit crater began to move instantaneously…The entire mass began to ripple and churn up, without

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