Tectonic setting of western British Columbia and Washington state.
Great earthquakes occur along part of the boundary between the two plates.
Schematic diagram illustrating interseismic and coseismic deformation associated with a subduction thrust fault. Source zone for Cascadia subduction earthquakes. This zone includes a completely locked section and a section transitional to free sliding along the thrust fault to the east. Origin of the main coastal features that provide evidence for subduction earthquakes in the Pacific Northwest.