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Mt. St. Helens

Mount St. Helens
Louwala-Clough
MSH82 st helens plume from harrys ridge 05-19-82.jpg
3,000 ft (1 km) steam plume on May 19, 1982, two years after its major eruption
Highest point
Elevation 8,363 ft (2,549 m)
Prominence 4,605 ft (1,404 m)
Coordinates 46°11′28″N 122°11′40″W / 46.1912000°N 122.1944000°W / 46.1912000; -122.1944000Coordinates: 46°11′28″N 122°11′40″W / 46.1912000°N 122.1944000°W / 46.1912000; -122.1944000
Geography
Mount St. Helens is located in Washington (state)
Mount St. Helens
Mount St. Helens
Skamania County, Washington, United States
Parent range Cascade Range
Topo map USGS Mount St. Helens
Geology
Age of rock < 40,000 yrs
Mountain type Active stratovolcano
Volcanic arc Cascade Volcanic Arc
Last eruption July 10, 2008
Climbing
First ascent 1853 by Thomas J. Dryer
Easiest route Hike via south slope of volcano (closest area near eruption site)

Mount St. Helens or Louwala-Clough (known as Lawetlat'la to the indigenous Cowlitz people, and Loowit to the Klickitat) is an active stratovolcano located in Skamania County, Washington, in the Pacific Northwest region of the United States. It is 96 miles (154 km) south of Seattle, Washington, and 50 miles (80 km) northeast of Portland, Oregon. Mount St. Helens takes its English name from the British diplomat Lord St Helens, a friend of explorer George Vancouver who made a survey of the area in the late 18th century. The volcano is located in the Cascade Range and is part of the Cascade Volcanic Arc, a segment of the Pacific Ring of Fire that includes over 160 active volcanoes. This volcano is well known for its ash explosions and pyroclastic flows.

Mount St. Helens is most notorious for its major 1980 eruption, the deadliest and most economically destructive volcanic event in the history of the United States. Fifty-seven people were killed; 250 homes, 47 bridges, 15 miles (24 km) of railways, and 185 miles (298 km) of highway were destroyed. A massive debris avalanche triggered by an earthquake measuring 5.1 on the Richter scale caused an eruption that reduced the elevation of the mountain's summit from 9,677 ft (2,950 m) to 8,363 ft (2,549 m), leaving a 1 mile (1.6 km) wide horseshoe-shaped crater. The debris avalanche was up to 0.7 cubic miles (2.9 km3) in volume. The Mount St. Helens National Volcanic Monument was created to preserve the volcano and allow for its aftermath to be scientifically studied.


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Wikipedia

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