Bloc Diagram Showing the Tectonic Plates in Southwestern British Columbia

Earthquakes in southwestern British Columbia occur in three distinct source regions:

1. relatively close to the surface in the North American Plate (continental crust)
2. deeper in the subducting Juan de Fuca Plate (oceanic crust)
3. along the boundary between the North American Plate and the subducting Juan de Fuca Plate (locked zone)

Source: Natural Resources Canada. Geofacts sheet “Earthquakes in Southwestern British Columbia”.