| Caption: |
Cross section (top) and map (bottom) of the plate tectonic setting of the Cascade Range showing major volcanoes and cities in their vicinity (see Figure 4.3 for the regional tectonic environment). The Juan de Fuca Plate, off the coast of northern California, Oregon, Washington, and Vancouver Island in British Columbia, is being subducted below the North American Plate (in green) along the Cascadia subduction zone. This subduction zone starts offshore along the line with the black triangles and descends beneath the North American Plate in the area with the wavy orange lines. Once the Juan de Fuca Plate reaches temperature and pressure conditions that allow it to partially melt, magma is produced. That magma rises to the surface to form the Cascade volcanoes. (Modified after Crandell, D. R., and Waldron, H. H. 1969. Disaster preparedness. Office of Emergency Preparedness) |
| Keywords: |
volcanoes, volcanism, volcanic eruptions, plate tectonics, tectonic plates, mid-ocean ridges, seafloor spreading, divergent boundary, divergent boundaries, oceanic lithosphere, oceanic crust, ocean basins, mantle upwelling, continental lithosphere, convergent boundary, convergent boundaries, subduction zones, trenches, North American Plate, San Andreas Fault, strike-slip faults, earthquakes, transform boundary, Juan de Fuca, Cocos, Nazca |
