: Mount St. Helens is an active stratovalcano in Skamania County, Washington, in the Pacific
Northwest region of the United States. It is located 96 miles south of Seattle and 53 miles northeast of
Portland, Oregon. The mountain is part of the Cascade Range. It is most famous for a catastrophic
eruption on May 18, 1980. That eruption was the most deadly and economically destructive volcanic
eruption in the history of the United States. In this paper, I intend to cover what factors caused the
eruption along with details regarding the geological features.
