Subduction Zone is a 600-mile fault that runs from northern California up to
British Columbia and is about 70-100 miles off the Pacific coast shoreline.
There have been 41 earthquakes in the last 10,000 years within this fault that
have occurred as few as 190 years or as much as 1200 years apart. The last
earthquake that occurred in this fault was on January 26, 1700, with an
estimated 9.0 magnitude. This earthquake caused the coastline to drop several
feet and a tsunami to form and crash into the land. What is most surprising is that
evidence for this great earthquake also came from Japan. Japanese historic
records indicate that a destructive distantly-produced tsunami struck their
coast on January 26, 1700. By studying the geological records and the flow of
the Pacific Ocean, scientists have been able to link the tsunami in Japan with
the great earthquake from the Pacific Northwest. Native American legends also
support to the timing of this last event.
the potential for a 9.0+ magnitude earthquake caused by the Cascadia Subduction
Zone and a resulting tsunami of up to 100 feet in height that will impact the
coastal area. There is an estimated 2-4 minutes of shaking or rolling that will
be felt along the coast line with the strength and intensity decreasing the
further inland you are.
Subduction Zone has not produced an earthquake since 1700 and is building up
pressure where the Juan de Fuca Plate is subsiding underneath the North
American plate. Currently, scientists are predicting that there is about a 40
percent chance that a megathrust earthquake of 9.0+ magnitude in this fault
zone will occur in the next 50 years. This event will be felt throughout the
current preparedness levels of Oregon, we can anticipate being without services
and assistance for at least 2 weeks, if not longer, when the Cascadia
Subduction Zone earthquake occurs. While this will be difficult to overcome,
our citizens, businesses, schools, government, and communities as a whole can
take steps to get prepared. Take action now by actively planning and preparing
yourself and your community to be ready for two weeks
Preparedness Information and Resources
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