I'll second the recommendation for tents in your preparation - around here its not certain how many structures might be habitable after an earthquake, but hopefully you can dig out your tents, and live in them. And aftershocks can number in the hundreds, so people may be living out of doors in the best non-lethal structures they can manage. I'm the proud owner of my family tent from when I was a kid, a big old canvas rig - army surplus from the Korean War era, housed generations of Scouts and was set up in our backyard all summer for years on end. Throw a blue tarp over and its even rain proof. Sleeps between 9 and 12, depending on number of kids etc. Over time I've also purchased some reliable brand tents in smaller sizes - something that will keep dry and sleep between 3 and 4. Camping gear like foam pads, sleeping bags, pillows etc naturally accumulates.