Mount St. Helens is a stratovolcano located in southern Washington, in the western part of the Cascade Mountain Range. It is about 100 miles south of Seattle, Washington and 50 miles northeast of Portland, Oregon. It is an eruptive volcanic cone built up of interlayered ash, pumice, lava flows, volcanic domes and other deposits. It is a young volcano. The first eruptions occurred about 40,000 years ago and it grew in a series of eruptive stages.
The most recent eruption series at Mount St. Helens began on May 18, 1980 at 8:32 AM. This eruption was catastrophic. To date it has been the deadliest and most costly volcanic eruption in the history of the United States. Fifty-seven people were killed and hundreds of square miles of landscape was covered by blast debris, ash, lahars and pyroclastic flows.
The Opportunity for Monitoring
Numerous other eruptions followed and these eruptions were used by researchers to learn more about monitoring volcanies, test equipment and refine monitoring techniques. In the videos at right, United States Geological Survey researchers explain how they learned from the eruptions and what their new information means for future volcanic monitoring efforts.
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United States Geological Survey scientists involved in resopnding do the 1980 eruption of Mount St Helens recount their experience, explain the impact of the eruption, its magnitude and what they learned about volcanoes. USGS video.
United States Geological Survey scientists . USGS video.