Mount St. Helens is a young volcano that developed over the last 40, 000 years within a very ruff terrain of meta volcanic rocks. Mount St. Helens was givens it s name some time between 1753 and 1839. This Volcano was named after Baron St.
Helens. The mountain was named by Commander George Vancouver and the officers of H. M. S. Discovery.
Mount St. Helens was known as “the Fuji of America” because its symmetrical appearance was similar to a famous Japanese volcano. The incredible cone top, whose shiny cap of perennial snow and ice is now almost gone. On May 18, 1980, the missing mountaintop was transformed in a few hours into the extensive volcanic ash that covered much of the Northwestern United States and into various other deposits closer to the mountain. Mount St. Helens was recognized as a volcano as early as 1835.
The peak rose more than 5, 000 feet above its base, where the lower side merge with near by ridges. The mountain is about 6 miles across at its base, which is an altitude close to 4, 400 feet on the northeastern side and about 4, 000 feet elsewhere. At the pre-eruption timberline the width of the cone was about 4 miles. The pre-eruption landscape was dominated by dense coniferous forests and clear streams and lakes. When Mount St. Helens erupted On May 18, 1980, after nearly two months of local earthquakes and steam eruptions, Mount St.
The Essay on Mount St Helens Ash Miles Eruption
... northern flank. These were destroyed in St. Helens' 1980 eruption. The first recorded sighting of Mount St. Helens by Europeans was by Royal Navy ... were destroyed. The eruption blew the top of the mountain off, reducing its summit from 9, 677 feet to 8, 364 feet in elevation ... and replacing it with a mile-wide crater. Like most of the other volcanoes in ...
Helens, suddenly began a major explosive eruption directed first northward and then upward. The lateral blast damaged and or covered more than 150 square miles of forest and recreation area, killed many animals, and left about 60 people dead or missing. The 9-hour eruption, the huge debris avalanche that immediately followed it, and the periodic eruptions during the following 3 days removed about 4 billion cubic yards of new magma like material and the upper and northern parts of the mountain, including about 170 million cubic yard of glacial snow and ice. The eruption cause many mudflows, the largest of which produced deposits so extensive and large that they reached and blocked the shipping channel of the Columbia River, which was about 70 river miles from the volcano. The eruption on May 18, 1980 blew volcanic ash consisting of heavily crushed, old rock from the mountain’s core as well as solidified new lava, more than 15 miles into the air. Winds carried the ash mostly eastward across the United States and in trace amounts, around the world.
The ash, which fell in extremely large amounts as far east as western Montana, harshly disrupted travel, caused widespread economic loss, and resulted in many other problems.
