Sequential physiographic diagrams of Mount St. Helens, Washington 1979-80

Visualizing Mt. St. Helens’ cataclysmic 1980 eruption.

This series of images was compiled by a team from the United States Geological Survey and published shortly after the 1980 eruption of Mt. St. Helens. Three views show the mountain in the Summer of 1979, May 15 (3 days before the eruption), and May 26, 1980. The ‘bulge’ of the underlying magma dome is clearly visible in the second diagram, followed by the massive crater that can be seen today. An inset in the lower right pinpoints the location of the mountain in relation to the rest of the Pacific Northwest.

The eruption of Mount St. Helens on May 18, 1980, was the most devastating volcanic event in U.S. history. Triggered by a series of earthquakes, the eruption destroyed over 200 square miles of forest and caused the deaths of 57 people. Ash from the eruption spread across nearly a dozen states and parts of Canada, disrupting air travel and affecting agriculture. The event drastically altered the landscape (lakes near the epicenter remain covered with fallen trees) and prompted major advances in volcano monitoring and emergency preparedness.