College of the Siskiyous

Local Geology

College of the Siskiyous is located at the western base of Mount Shasta, a 14,162-foot high stratovolcano that has been built by eruptions during the past 200,000 years. The campus is also set close against the eastern flank of the Eddy Range, part of the Klamath Mountain system that stretches 150 km westward to the coast. Volcanism in the High Cascades and earthquakes beneath both the Klamaths and the Cascades are occurring in response to subduction of oceanic lithosphere beneath northern California. To learn more about regional volcanism and seismicity visit one or more of the following sites:

  • Geologic Provinces of the United States—Cascade Volcanoes: Brief, non-technical introduction to subduction in the Pacific Northwest and the origin of the Cascade volcanic chain. [US Geological Survey and National Park Service]
  • Assessment of Volcanic Threat and Monitoring Capabilities in the United States: A report that evaluates the threats posed by 169 volcanoes and volcanic fields in the conterminous United States, Alaska, Hawaii, and the Marianas Islands. The report ranks Mount Shasta as the nation's fifth highest risk volcano. [United States Geological Survey]
  • California Volcano Information: Summaries of the eruptive histories and potential hazards of California's volcanoes as well as updates on their current statuses. [USGS California Volcano Observatory]
  • Global Earthquake Information: Interactive map and list for earthquakes that have occurred around the world during the past day. [USGS, CDMG and seismological programs at several regional universities]
  • Mount Shasta Monitoring Map: To see what's up in the Mount Shasta area, click on any of the black triangles to see the seismogram from that station for the past 24 hours. Clicking on a blue triangle shows GPS data for the last 24 hours at that site. [USGS Earthquake Hazards Program]


For information or questions regarding this or other programs at College of the Siskiyous contact the Office of Instruction.

Email: Office of Instruction
Phone: (530) 938-5201