Memorable volcano eruptions from the past
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Mt. St. Helens, Wash.( USGS / Cascades Volcano Observatory / August 11, 2013 )
A magnitude 5.1 earthquake struck beneath Mt. St. Helens on May 18, 1980, triggering an eruption (VEI 5) that would last for more than nine hours, blast hot gas, steam and rock debris as many as 15 miles above sea level and send about 540 million tons of ash across Western United States at 60 mph. The eruption killed 57 people.
Pictured: A closeup of the May 18, 1980, ash plume.
U.S. Geological Survey: Mt. St. Helens, Wash.