Mount St. Helen is a volcano located along the cascade range, which is a volcano chain
stretching from Northern California to British Columbia. Mount St Helen now stands at a height
of 8,364 feet above sea level. Mount St. Helen was one the smaller eruptions of five major
ones in Washington State. It's elevation before the eruption was 9,677 feet high. On March
29, 1980 after a period of one-hundred and twenty-three years of inactivity a earthquake under
As magma pushed up from beneath the earth's surface, the north side of the mountain
developed a bulge. Angle and slope-distance measurements indicating that the bulge was
growing at a rate of 1.5 feet per day (thompson pg 23). May 17 the volcano's north side
had been pushed upward and outward 450 feet (thompson pg 24). May 18 at 8:32
a.m. Pacific daylight time a magnitude 5.1 out of a possible 10 earthquake shook Mount St. Helen.
The bulge on the north side of the mountain gave way in a gigantic rock slide releasing pressure
and triggering a major rock and pumice eruption. At thirteen hundred feet the peak collapsed and
as a result 24 square miles of the valley was filled with roc and debris. From the rock slide 250
square miles of timber, recreation, and private lands were demolished from the lateral blast. For
more than 9 hours the volcano spit ashes out to the air. Eventually the ashes reached 12-15 miles
above sea level. The ashes went eastward at about 60 miles per hour. By noon the ashes had
reached as far as Idaho. Ashes reached 11 states. The total amount of ash that fell was .26
cubic miles or enough ash to cover a football field to a depth of 150 miles (thompson pg 26).
Mount St. Helen is said to have caused the most damage of any other volcano blast
(Carson pg11). A total of 1.6 billion dollars of damage was caused by the blast
...