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Maps related to Mount St. Helens.

Rebuilding Mount St. Helens

On May 18, 1980, Mount St. Helens, Washington exploded in a spectacular and devastating eruption that shocked the world. The eruption, one of the most powerful in the history of the United States, removed 2.7 cubic kilometers of rock from the volcano's edifice, the bulk of which had been constructed by nearly 4,000 years of lava-dome-building eruptions. In seconds, the mountain's summit elevation

Geologic map of the Sasquatch Steps area, north flank of Mount St. Helens, Washington

The 1980 eruption of Mount St. Helens resulted in both new volcanic deposits and deeply incised exposures into pre-1980 deposits. These exposures were produced by excavation of the crater by the 1980 landslides and lateral explosion as well as the subsequent erosion of Step and Loowit creeks by northerly stream flow out of the horseshoe-shaped crater. The map covers the area known as the Sasquatch

Physiographic diagrams of the May 18, 1980, landslide-eruption of Mount St. Helens, Washington

This sequence of diagrams shows the complex series of events that culminated in the catastrophic eruption of Mount St. Helens on the morning of May 18, 1980.