Deep earthquakes pose a serious risk to Cascadia. In Puget Sound, for example, there is an 84% chance of a magnitude 6.5 or greater deep earthquake striking within 50 years. Beneath northwestern California, northwestern Oregon and southwestern British Columbia the probability of a similar sized earthquake over 50 years is somewhat lower, but still a major component of the earthquake hazard in each area.
This report discusses characteristics typical with earthquakes in the Cascadia region, potential hazards they cause, lessons from recent earthquakes, potential earthquakes and lessons for the future.