The Volcanic Eruption of Mount Saint Helens Essay

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The Volcanic Eruption of Mount Saint Helens

On the 18th of May 1980 mount saint. Helens Erupted all thought Mount Saint Helens is a volcano the eruption in 1980 was actually caused by an earthquake the earthquake was 5.0 on the Richter scale. The tremor trigged the biggest landslide ever recorded this was due to molten rock movement.

Mount Saint Helens is part of the Cascade Range which has numerous volcanoes thought Mount Saint Helens is the most active.

Text Box: Fig 1[IMAGE]There are many causes of the Mount Saint Helens eruptions. To begin with the area North West USA is at the boundary of two plates the Pacific and North American Plate, this is a conservative plate margin with the
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The earthquake of the 18th May 1980 was connected with this movement

The Volcanic Eruption of Mount Saint Helens had a huge effect on the landscape this was to the sheer power of what happened, firstly the 5.0RM Earthquake trigged the upper north flank to collapse which in turn became a major landslide. The collapse of the north flank produced the largest landslide avalanche recorded in historic time. The initial blast of incandescent gas fluidise magma which vented thought at velocity of 50m per second the descending landslide. The sudden removal of the upper part of the volcano by the landslides triggered the almost instantaneous expansion (explosion) of high temperature-high pressure steam present in cracks and voids in the volcano and of gases dissolved in the magma that caused the bulge. The altitude of the volcano had been reduced by 400m thousand of trees uprooted leaving a barren landscape. 20km down the north fork of the Toutle River the valley flow had raised by 90 meters due to dumped material. Mudflows melted a summit snow and glacier ice containing over 46 billion gallons of water travailing at 80km per hour depositing large debris (up 130m thick) from the collapsing column of air borne particles. Ash was deposited to distance over 900km away from Mount Saint Helens. Also huge areas of animal habitat were destroyed along with a

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