12/08/2016
Today’s 6.5 earthquake off the coast of northern California is a reminder that we need to prepare now for the Cascadia subduction zone earthquake. Today’s temblor was located on the Gorda Escarpment, stretching several hundred miles west of Mendocino. This is very close to where the great Cascadia earthquake will likely begin.
This one didn't start the avalanche of quakes that will be the Cascadia event so there is no immediate cause for alarm, but the Gordo Escarpment marks the southern end of the Cascadia subduction zone, which is something to worry about.
Sometime a relatively small quake on the Gordo Escarpment will, in fact, trigger a much bigger quake in the subduction zone, which will trigger another quake further north and the Great Cascadia Subduction Zone Earthquake will be off and running. It didn't happen this time, but the Gordo Escarpment, the Gordo Plate, and the Cascadia subduction zone all come together at the Mendocino Triple Junction, just off the coast of Mendocino.
There are a lot of earthquakes under the Gordo ridge, by far more than anywhere else in California. No one can predict when one will trigger the cascading earthquake that will affect the West Coast all the way from northern California to Vancouver, BC. The last time it happened was January 1700. The average time between events is about 270 years, and it has been 317 years since the last one.
Now is the time to prepare. Afterward will be too late. If you’d like expert help in preparing your household and your neighborhood for the Big One, we are available.