Mount St. Helens

Mount St . Helens

Geographic Facts and Overview

Elevation : 8 , 635 feet (2 ,550 m

Prominence : 4 , 605 feet (1 ,404 m

Coordinates : 46 ?12 '00 .17 'N , 122 ?11 '21 .13 'W

Age of rock 40 ,000 years

Easiest access : southern slope

Mount St . Helens is an active stratovolcano in Skamania County Washington , in the Pacific Northwest region of the United States . It is located 96 miles south of the city of Seattle and 53 miles northeast of Portland , Oregon . Mount St . Helens takes its name from the British

diplomat Lord St Helens , a friend of George Vancouver , who did a survey of this place in the late 1800s . The mountain can be found in the Cascade Range and is part the Cascade Volcanic Arc , a segment of the Pacific Ring of Fire that includes over 160 active volcanoes (Mount St Helens . This volcano is quite well known for its ash explosions and pyroclastic flows . It is located 45 miles west of Mount Adams , in the western part of the Cascade Range . These volcanic mountains are each approximately 50 miles from Mount Rainier , the highest of Cascade volcanoes . Mount Hood , the nearest major volcanic peak in Oregon , is 60 miles (95 km ) southeast of Mount St . Helens (Mount St . Helens

Mount St . Helens is quite young compared to the other well-known Cascade volcanoes (Mount St . Helens . It only formed within the last 40 ,000 years , and the summit cone (before the 1980 eruption ) began rising around 2000 years ago . The volcano is still considered the most active in the Cascades within the last 10 ,000 or so years , according to the Mount St . Helens report in Wikipedia

Mount St . Helens Eruptive History

The early eruptive stages of Mount St . Helens are known as the "Ape Canyon Stage (around 40-35 ,000 years ago , the "Cougar Stage (ca 20-18 ,000 years ago , and the "Swift Creek Stage (roughly 13-8 ,000 years ago .The modern period , since about 2500 BC , is called the "Spirit Lake Stage (Mount St . Helens ) Collectively , the pre-Spirit Lake Stages are known as the "ancestral stages (Mount St . Helens

The Eruption of May 18 , 1980

Mount St . Helens erupts maybe around once each century . After lying asleep for 123 years , Mount St . Helens again spewed steam and ash on March 27 , 1980 - a prelude that put geologists on alert . But what happened on the18th of May , 1980 , went beyond what anyone had envisioned . According to Mount Saint Helens History report , a 5 .1 magnitude earthquake from inside the volcano triggered the destruction of its north flank , letting down the largest landslide in recorded history and a volcanic eruption equal in power to 500 atom bombs (History . As much as a cubic mile of volcanic material shot upward and sideways . The blast traveled at more than 300 miles per hour with temperatures in excess of 600 degrees F , destroying 230 square miles of forest (History . Within seconds , the trunks of thousands of 150-foot-tall old-growth Douglas firs snapped like toothpicks . Ash...