I lived in the San Francisco area for many, many years. I was there for the big 1989 earthquake.
To me the MOST important thing is to live in a builidng that has been built to current code or has had a major retrofit. The . The other suggestions are very good, but the structural integrity of the building is crucial.
My apartment was about 6 months old in 1989, and I lived on land fill but I had absolutely no damage because of the way it was built. People a few blocks away in older buildings had major structural damage.
I was at my office during the earthquake, and they had just completed a major earthquake retrofit - fairly expensive but boy was it worth it. What was a MAJOR earthquake (remember the bridge collapsing,etc) did no damage. I didn't even have a pencil roll off of my desk.
I've been through earthquake, tornado, and a couple of hurricanes. I'd take the earthquake any day.