On May 18, 1980 after 2 months of local earthquakes and steam eruptions, picturesque Mount St. Helens, a Cascade Range volcano is southwestern Washington, suddenly began a major explosive eruption directed first northward and then upward. The lateral blast, which lasted only the first few minutes of a 9 hour continuous eruption, devastated more than 150 square miles of forest and recreation are…
This work provides a detailed picture of the rockslide-debris avalanches of the May 18, 1980, eruption of Mount St. Helens Volcano. The work provides a characterization of the deposit, a reinterpretation of the details of the first minutes of the eruption of May 18, and insight into the transport mechanism of the mass movement.