Mount St. Helens, Washington, USA, 1973

Mount St. Helens is an active stratovolcano in southwest Washington State.  This image was acquired September 15, 1973 by the Landsat 1 satellite. 

On May 18, 1980, a major volcanic eruption occurred at Mount St. Helens. The eruption was preceded by a series of earthquakes and steam-venting episodes, and an earthquake on May 18 caused the entire weakened north face to slide away, creating the largest landslide ever recorded. This allowed the high-pressure gas and steam to suddenly explode northwards. It has often been declared as the most disastrous volcanic eruption in U.S. history.

Visit Earthshots: Satellite Images of Environmental Change to read more about this area, and to learn how how satellite imagery is used to track change over time around the world.