Mount St. Helens, Washington

Credit: Credit: NASA, Posted on: Monday, 17 May 2004, 06:00 CDT Download full size image

On May 18, 1980, Mount Saint Helens volcano erupted. A series of earthquakes preceded the eruption, triggering a collapse of the north side of the mountain into a massive landslide. This avalanche coincided with a huge explosion that destroyed over 700 square kilometers (270 square miles) of forest in a few seconds, and sent a billowing cloud of ash and smoke 24,000 meters (80,000 feet) into the atmosphere. Because the eruption occurred in an easily accessible region of the U.S., Mount St. Helens has provided unprecedented opportunities for US researchers to collect scientific observations of the geology of an active volcano and document the regional ecological impact and recovery from an eruption. In the center of the crater sits a lava dome that is 876 feet above the crater floor and is about 3,500 feet in diameter. The dome began to form after the 1980 eruption, but there have been no dome building eruptions for more than a decade.

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