Volcanoes – Mount St. Helens Eruption 1980

Volcanoes – Mount St. Helens Eruption 1980

Introduction:

Mount St. Helens is situated in North America on the North American plate. It is the peak of the fold mountain range in North America. The fold mountain range was formed around 70 million years ago when a convergent plate boundary, Juan De Fuca Plate (Oceanic Crust), collided with the North American Plate (Continental Crust). The oceanic crust was forced downwards into the mantle causing it to turn into magma. Then the pressure increased in the mantle causing the magma to rise up onto the earth’s surface. This lead to volcanic eruptions. Many more volcanic eruptions happened at the plate boundary forming Mount St. Helens. Altogether 13 volcano peaks were formed (including Mount St. Helens). This is called the Cascade Range.

Mount St. Helens is the youngest and most deadly of the 13 volcanoes in the Cascade Range. The geologists call Mount St. Helens a composite volcano. It is called this because of its steep sides an...