- The West Coast of North America includes the ~1000km long Cascadia Subduction Zone that extends from northern California through western Oregon and Washington to into southern British Columbia. The Juan de Fuca tectonic plate is subducting beneath the North American Plate.
- Two parallel mountain ranges have been produced – Coast Ranges (accretionary wedge) and The Cascades (volcanic arc).
- The Cascades is a ~700 mile long line of active volcanoes formed as deep subducted material began to melt, releasing fluids, and magma rose to the surface forming many volcanic systems.
- There are 20# major volcanic systems and over 4000# volcanic vents. In recent times, the 1980 eruption of Mount St Helens was an example of major volcanic energy release here. Other large volcanic systems include Mount Adams, Mount Rainier, Glacier Peak, Mount Baker, and Lassen Peak (1915 eruption). There were 8# eruptions from 1800-1857 across these volcanic systems.
- The Cascade Volcano Observatory (CVO) monitors the region for volcanic and seismic activity. With the long fault areas, this subduction zone can have very large earthquakes (e.g., the Cascadia earthquake of 1700 are Mw 8.7-9.2)
- Geothermal research here has studied deep EGS resources as well as shallow hydrothermal resources. The presence of active volcanic systems offers the potential of associated hydrothermal resources.
