a detailed and accurate explanation of the causes of mount st helens erupting

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Asked 10/23/2008 10:59:05 AM

Updated 125 days ago|5/31/2023 11:49:20 PM

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User: a detailed and accurate explanation of the causes of mount st helens erupting

Weegy: Before the eruption in 1980, Mount St. Helens was the fifth-highest peak in Washington. The peak rose more than 5,000 feet (1,525 m) above its base, where it rises from the ridges that are around it. [ It stood out from the surrounding hills because of the symmetrical cone shape and the snow that covered the top. Because of its cone-shape, it was called the "Mount Fuji of America", after the famous Mount Fuji which is a symbol of Japan.[2] [change] Modern eruptions Mount St. Helens erupted on May 18, 1980, at 08:32 a.m. Pacific Daylight Time. [change] May 18, 1980 In the months before the large eruption that took place on May 18, 1980, there were many signs of volcanic activity. On March 20, 1980, Mount St. Helens was the center of a magnitude 4.2 earthquake.[1] Steam venting from the volcano started on March 27.[3] By the end of April, the north side of the volcano started to grow larger.[4] On May 18, a second earthquake of magnitude 5.1 made a huge part of the north face of the volcano collapse. It was the largest known debris avalanche in recorded history. At 08:32 a.m. Pacific Daylight Time, the magma inside of St. Helens exploded. On the Volcanic Explosivity Index scale, the eruption was rated a five, which is the same rating of the famous Vesuvius eruption in 79 AD. For more than nine hours, ash erupted from the volcano, rising into the air for 12 to 16 miles (20 to 27 km) above sea level in the air. (The gas rising from a volcano is a "plume")[5] The pyroclastic flow of heated rocks and gas that poured out of the Volcano spread over an area of over 230 square miles (600 km²), destroying plants and buildings. The ash spread east at about 60 miles per hour (95 km/h), with some ash reaching Idaho by about 12:00 PM, almost 3.5 hours after the eruption. By about 5:30 p.m. the plume of ash became smaller. Through the night and for several days after, there were smaller eruptions. As well as the effect of the fast-moving hot gasses and stones from the explosion, the collapse of the northern side of Mount St. Helens caused lahars, or volcanic mudflows. These were mixtures of volcanic ash with melted ice and snow. ]

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Asked 10/23/2008 10:59:05 AM

Updated 125 days ago|5/31/2023 11:49:20 PM

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KuyaBert_09

The eruption of Mount St. Helens in 1980 was caused by tectonic activity and the buildup of magma, resulting in a devastating explosion and significant landscape changes.

Added 125 days ago|5/31/2023 11:49:16 PM

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