May 18, 1980. On that fateful day, Mount St. Helens Volcano in Washington exploded violently after 2 months of intense earthquake activity and intermittent, relatively weak eruptions, causing the worst volcanic disaster in the recorded history the United States. The cataclysmic eruption and related events May 18 rank among the most significant geologic events in the United States during the 20th century. The processes, effects, and products of the chain of events were the most intensively studied and photographically documented of any explosive volcanic eruption in the world to date. The wealth of data on Mount St. Helens before, during, and after the May 18 eruption enabled geoscientists of the U.S. Geological Survey (USGS), the University of Washington, and other research institutions in the United States and abroad to put into perspective the devastating impact of suddenly unleashed volcanic energy. -- Tilling, et.al., 1990 |