I've lived through two significant quakes while in California.
The first was the quake in '71 just north of the Los Angeles area. That was very freaky because everyone thought it was the end of the world as it was happening. No injuries buts lots of cracks in our apartment house as well as many things coming off the walls and tables, etc. Minor loss of possessions but nothing major.
The second one was the Loma Prieta quake in '89 south of San Francisco that millions around the world watched as it happened on TV during the world series. I was at work at the time and all of the ceiling tiles and overhead lights all came down on top of me. Fortunately I had time to get beside my desk just as everything began to fall around me. No major damage to the structure but power was out for several days. Lost some stuff at home but nothing significant. One really feels very helpless during the event because you literally can't do anything but hang on and hope something doesn't hit you in the head or fall and crush you.
One thing we were taught at work was to NEVER get under a desk or table but to get down low BETWEEN office furniture such as desks, file cabinets, tables, etc. Getting under something is just asking to be crushed. There is more space to survive in between things than under them should the ceiling cave in or the floor above collapse. The same goes if you are at home when a quake hits. Quickly get between something but not under it. And, of course, stay away from windows and glass doorways which can literally explode from sideway pressures on the framing.