A subduction earthquake off the coast of Oregon would destroy all west coast US ports and destroy almost all of the west coast agriculture that supplies much of North America with fruit 'n veggies.
Within hours of a subduction earthquake when it becomes clear the ports have been destroyed and major transportation routes and dams have been chewed up... people will clean out the food from every grocery store in all of North America and we will be plunged into a FOOD CRISIS that will last for YEARS as 300 million + North Americans try and find enough food to survive.
Honest to Pete... if you don't have a sizeable food storage built up by now... you'd better start right away.