Create a 5 pages page paper that discusses the volcanic eruption of mount saint helens. According to Glicken, the mountain had been calm for a long period prior to the 18 May eruption. Located in south-central Washington, St Helens Mountain was a symmetrical cone with an elevation of 2950 meters up to the peak prior to the eruption. The mountain also supported about 13 glaciers.
Two months prior to the eruption, the United States Geological Survey in Washington reported a series of earthquakes around the mountain’s region. . The first earthquake tremor on the mountain measuring 4.1 on the Richter scale was recorded on March 20, 1980 (Glicken 28). After the first earthquake, over forty earth tremors per hour were recorded in the mountain by 25 March that year. . Two days later on 27 March 1980, the first explosion occurred in the mountain, releasing volcanic ash and steam up to a distance of about four miles in the atmosphere (Vallance et al, 171). .
The explosion caused a visible crater on the peak of the mountain peak that was covered with snow. According to Glicken (38), the resulting crater measured about 250 feet wide and sixty feet deep. This observation prompted the emergency and disaster organizations in the area to start evacuating people to safety. . A second eruption occurred at night of the same day, releasing steam and crushed rocks to an altitude of about four miles above the peak of the mountain. . The second explosion created another crater that was observed the following day on 28 March 1980. . According to Vallance, et al (173) both craters joined after a series of eruptions, forming a 2000 feet long and 500 feet deep crater. . Two days later on March 20, a phreatic eruption occurred on the mountain. The phreatic eruption was caused by the contact of the rising hot lava with water melting from the ice cap resulting in a steam explosion (Glicken, 53).
A series of phreatic eruptions occurred the same day accompanied by strong earth tremors varying in intensity from 3.3 to 4.4 on the Richter scale (Galvin). . Following these events, the local governor declared a state of emergency and security forces were called to control the increasing number of people witnessing the event. . .