it is seldom dangerous to people. It moves about two to three miles per hour. NAMED for: Mount St. Helens was named for the British diplomat Alleyne Fitzherbert (1753-1839) whose title was Baron St. Helens. The mountain was named by Commander George Vancouver and the officers of the H.M.S. Discovery while they were surveying the northern Pacific coast form 1792- 1794 Location Mt. St. H is part of the Cascade Range which is a chain of volcanoes that runs from Northern California northward to British Columbia. MSH is about 95 miles south of Seattle, Washington MSH was 9,677 ft high before its eruption in 1980. It is now 8,364 feet high and about six miles wide at its base. The eruptions from this volcano were the first to happen in the continental United States except for Alaska since 1921 when Lassen Peak last erupted. MSH is 34 miles west of Mount Adams in the eastern part of the Cascade range. These "brother and sister" volcanic mountains are bout 50 miles from Mount Rainier. Mount Hood, the nearest major volcanic peak in Oregon, is about 60 miles southeast of MSH. The other volcanoes in the Cascade range are Mount Rainier, Mount Baker, Mount Adams, Mount Hood, Mount Jefferson, Three Sisters, Newbury, Mount Mazama, Mount Shasta, Medicine Lake Highland and Lassen Peak. MSH has erupted many times in the past 4,500 years, but was inactive from 1857 until its eruption in 1980. The volcanic eruptions in the Cascade Range have been: Mount Baker: 1870 Mount Rainier Mount St. Helens: 1980, 1831-11857 Mount Adams: 3,000-4,000 years ago Mount Hood: 1865 Mount Jefferson: 1030 years ago Three Sisters: 2500 years ago Newbury: 1400 years ago Mount Mazama: 6600 years ago Mount Shasta: 1840, 1786 Lassen Peak: 1914-1921 Medicine Lake Highland: 1910 The Volcanic Explosivity Index, or VEI describes the size of volcanoes based on three observations. A volcano is rated VEI -2, VEI -3 etc. on its violence of eruption, height of the plume that shoots out of ...
