How was mount st helens formed
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Mount St. Helens, located in southwestern Washington about 50 miles northeast of Portland, Oregon, is one of several
lofty volcanic peaks that dominate the Cascade Range of the Pacific Northwest; the range extends from Mount
Garibaldi in British Columbia, Canada, to Lassen Peak in northern California. Geologists call Mount St. Helens a
composite volcano (or stratovolcano), a term for steepsided, often symmetrical cones constructed of alternating layers
of lava flows, ash, and other volcanic debris. Composite volcanoes tend to erupt explosively and pose considerable
danger to nearby life and property. In contrast, the gently sloping shield volcanoes, such as those in Hawaii, typically
erupt nonexplosively, producing fluid lavas that can flow great distances from the active vents. Although Hawaiian-type
eruptions may destroy property, they rarely cause death or injury. Before 1980, snow-capped, gracefully symmetrical
Mount St. Helens was known as the "Fujiyama of America." Mount St. Helens, other active Cascade volcanoes, and
those of Alaska form the North Ameri
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Mount St. Helens
Mount St. Helens | |
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3,000-foot (910 m) steam"plume" on May 19, 1982, two years after its major eruption | |
Elevation | 8,365 ft (2,550 m) |
Prominence | 4,605 ft (1,404 m) |
Coordinates | 46°11′28″N122°11′40″W / 46.1912000°N 122.1944000°W / 46.1912000; -122.1944000[1] |
Location | Skamania County, Washington, U.S. |
Parent range | Cascade Range |
Topo map | USGS Mount St. Helens |
Age of rock | < 40,000 yrs |
Mountain type | Active stratovolcano |
Volcanic arc | Cascade Volcanic Arc |
Last eruption | 2004 – July 10, 2008 |
First ascent | 1853 by Thomas J. Dryer |
Easiest route | Hike via south slope of volcano (closest area near eruption site) |
Mount St. Helens is a volcano in the U.S. state of Washington. It is 96 miles (154 km) south of Seattle and 53 miles (85 km) northeast of Portland, Oregon. The volcano is in Cascade Range of mountains. It is part of the Cascade Volcanic Arc in the Pacific Ring of Fire that includes over 160 active volcanos. This is a deadly volcano.
Moun
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Mount St. Helens
Volcano in Washington, U.S.
This article is about the volcano in Washington state. For the mountain in California, see Mount Saint Helena. For more information about the volcano's 1980 eruption, see 1980 eruption of Mount St. Helens.
Mount St. Helens | |
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3,000 ft (0.9 km) high steam plume on May 19, 1982, two years after the 1980 major eruption | |
Elevation | 8,363 ft (2,549 m) |
Prominence | 4,605 ft (1,404 m) |
Listing | |
Coordinates | 46°11′28″N122°11′40″W / 46.1912000°N 122.1944000°W / 46.1912000; -122.1944000[1] |
Etymology | Alleyne FitzHerbert, 1st Baron St Helens |
Native name | |
Mount St. Helens Location in Washington state | |
Parent range | Cascade Range |
Topo map | USGS Mount St. Helens |
Rock age | Less than 40,000 years old |
Mountain type | Active stratovolcano (Subduction zone) |
Volcanic arc | Cascade Volcanic Arc |
Last eruption | 2004–2008 |
First ascent | 1853 by Thomas J. Dryer |
Easiest route | Hike via south slope of volcano (closest area near eruption
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