Copyright Information: All images are in the public domain and available for free. If you use this image, credit NOAA/NGDC, Department of Natural Resources, State of Washington. |
Uprooted trees in the ash-covered Green River valley. A small debris flow is visible on the left. Trees amounting to more than 4 billion board feet of salable timber were damaged or destroyed by the near-supersonic lateral blast of rock, ash, and hot gases. The blast devastated an area of about 230 square miles in a fan-shaped sector north of the volcano. At least 25 percent of the damaged timber was later salvaged. The photo was taken on May 24, 1980. Image Credit: Department of Natural Resources, State of Washington May 18, 1980 Mount Saint Helens USA volcano An earthquake occurred at 15 32 UT, only seconds before the explosion that began the eruption of Mount St. Helens volcano. This eruption and blast blew off the top of the volcano, reducing its elevation by 396 meters, killed 31 people and caused an estimated property damage of between $0.5 billion and $2 billion. About 53 earthquakes having magnitude larger than 4.5 were located near Mount St. Helens before the main event and eruption. No earthquakes having magnitudes higher than 4.5 were located following the eruption. |
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