Medicine Lake Volcano Medicine Lake Volcano Medicine Lake Volcano is a large shield volcano in northeastern California about 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 thick shield is from east to west and from north to south, and covers more than . The underlying rock has downwarped by under the center of the volcano. The volcano is primarily composed of basalt and basaltic andesite lava flows, and has a caldera at the center. The Medicine Lake shield rises about above
Volcano tectonic earthquake Volcano tectonic earthquake A volcano tectonic earthquake is an earthquake induced by the movement (injection or withdrawal) of magma. The movement results in pressure changes in the rock around where the magma has experienced stress. At some point, the rock may break or move. The earthquakes may also be related to dike intrusion and may occur as earthquake swarms. An example is the 2007–2008 Nazko earthquake swarm in central British Columbia, Canada. Other types of seismic activity related to volcanoes and their eruptions are long period seismic waves, which are from sudden sporadic movement of magma, which is blocked from