Mt. St. Helens is a stratovolcano part of a group of volcanoes called The Ring of Fire. These are created from the convergence/subduction between the Juan De Fuca plate and the North American plates. Its most common type of eruption is intermediate eruptions, which is what the composition was in its most recent eruption. Mt. St. Helens most recently erupted on May 18, 1980. An earthquake right under the mountain caused an enormous landslide/avalanche going close to 150 mph. A huge hazard from this event was the pyroclastic flows, which were allowed to escape because the landslide reduced the pressure keeping it in there. Extremely hot ash, poisonous gases, and lava fragments flowed down the mountain at speeds quicker than 200 mph. Mt. St
