آتشفشان بعد زلزله

Saturday, 18 May 2013 marks the 33rd anniversary of the cataclysmic eruption of Mount St. Helens in Washington. A magnitude 5+ earthquake accompanied a massive landslide that uncorked the volcanic plumbing system. The subsequent lateral blast destroyed vegetation hundreds of square miles surrounding the volcano, and the 9-hour long Plinian-style eruption produced pyroclastic flows and sent an ash plume high into the atmosphere, which fell on communities nearly 950 miles away. This eruption and subsequent research at Mount St. Helens has contributed an immeasurable wealth of information about volcanic processes to the scientific community. The state of Washington commemorates the eruption by celebrating Volcano Awareness Month. Read more about this and other eruptions of Mount St. Helens here:http://volcanoes.usgs.gov/volcanoes/st_helens/ (photo of Plinian plume by Austin Post)

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