The 1980 eruption of Mount St. Helens is surpased by a volcano that was formed in 1912 located where?
1980 eruption of Mount St. Helens On May 18, 1980, a major volcanic eruption occurred at Mount St. Helens, a volcano located in Skamania County, in the state of Washington, United States. The eruption (a VEI 5 event) was the only significant volcanic eruption to occur in the contiguous 48 U.S. states since the 1915 eruption of Lassen Peak in California. However, it has often been declared as the most disastrous volcanic eruption in United States history. The eruption was preceded by a two-month series of earthquakes and steam-venting episodes, caused by an injection of magma at shallow depth below the volcano that created a large bulge and a fracture system on the mountain's north slope.
Medicine Lake Volcano Medicine Lake Volcano is a large shield volcano in northeastern California about 50 km northeast of Mount Shasta. The volcano is located in a zone of east-west crustal extension east of the main axis of the Cascade Volcanic Arc and the Cascade Range. The 1 km thick shield is 35 km from east to west and 45 to from north to south, and covers more than 2000 km2 . The underlying rock has downwarped by 0.5 km under the center of the volcano. The volcano is primarily composed of basalt and basaltic andesite lava flows, and has a 7 by caldera at the center.