There is a theory now that the San Andreas and the Cascadia zone could be linked.
As a Californian, that concerns me. By "linked" do you mean physically connected as one giant fault? Or just that earthquakes in one could precipitate quakes in the other fault?
After the 2011 Japan quake, they say that all that stress that was released was transferred further south to the Tokyo region. Unfortunately, we don't know if that stress will release in another megaquake tomorrow or 50 years from now.