Eruption Of Mount Saint Helens

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Eruption of Mount St. Helens 1980 On May 18, 1980, Mount St. Helens erupted and killed fifty-seven people. This was the most recent earthquake in the main forty-eight states since 1915. Mount St. Helens is a stratovolcano located in the state of Washington. A stratovolcano is made up of hardened pumice and lava. Before 1980, the last eruption of Mount St. Helens was between 1840 and 1850. The volcano did not happen overnight however, it was caused by multiple earthquakes and lots of pressure buildup through time. The Mount St. Helens volcano eruption was the most recent volcanic eruption that did significant damage in the United States. The formation of Mount St. Helens millions of years ago is the reason why the eruption was so violent. The Juan de Fuca Ridge, which lies between the Pacific and Juan de Fuca plate pushes the two plates in opposite directions causing the Juan de Fuca plate to sub duct underneath the continental plate causing a subduction zone and large pieces of rock are pushed into the opposite plate causing a mountain to form. The magma that the Mount St. Helens produces rises from the mantle to inside the volcano when water is released and the material becomes less dense and it’s melting temperature is lowered, causing it to rise up. The magma sits in the magma chamber and volatiles and minerals are slowly released from the magma because of pressure. Eventually, the magma creates too big of a blockage of the volcanic cone and causes a sudden, explosive eruption, much like that of 1980. From 1840 to 1850 until 1980, Mount St. Helens remained dormant and had no signs of activity, which is common for stratovolcanoes. Many stratovolcanoes have long dormant periods followed by active periods. On March 15, 1980 three small earthquakes were recorded on seismographs that happened underneath the mountain. Scientists believe that the earthquakes
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