All volcano eruptions are
caused by little earthquakes underneath the volcano. Many small earthquakes
had shaken the mountain, but none big enough to make it erupt.
In July of 1971, the first big earthquake made Mount St. Helen's erupt.
The earthquake had a magnitude of 5.1. This July earthquake
was too much for Mount St. Helen's; it erupted suddenly without much warning
to the people. The lava melted the ice on the top of the mountain
and made the rapids of Toutle River change from relaxing rapids to a speed
of one hundered seventy miles per hour. All the lava had wiped out
the whole north side of the mountain causing the largest landslide
ever. This caused Mount St. Helen's to go from the ninth largest
mountain to the thirtieth largest mountain. Its height, before the
eruption, was nine thousand six hundred seventy seven feet; it shrank to
eight thousand three hundered sixty-five feet. Mount St. Helen's
was a very calamitous disaster.
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