well you just have 2 watch your self no matter where you move around here
its quite interesting around cali 
Grew up in Santa Cruz. Yes, it's definitely on a fault line. That's the epicenter of the 7.1 earthquake in 1989. The whole county basically got annihilated. Had to dig my friend's grandmother out of a collapsed drug store. Took 15 years to rebuild, has never been quite what it was before.
Santa Barbara/ventura? Just a guess. Maybe San Luis Obisbo? Not sure if Sonoma has quakes, but that might be a solid choice. I know there are places up there with a mellow attitude. I've never heard about Mendo having a big quake either.
The good news is that Santa Cruz no longer has brick buildings anymore. It turns out that during an Earthquake brick buildings transform into brick launching death machines. They pretty much all fell down in 89 and the county doesn't allow new ones being built.
Humboldt is a big place. I know Eureka has them frequently. Dunno about Southern Humboldt.
