May 1980 Mount Saint Helens, USA Images |
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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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