Something everyone should know is where the water and gas mains are located and how to turn them off if necessary. Gas lines in particular are dangerous if they're broken in a quake because they can ignite a fire.
For peace of mind whether you're at home or away, the Automatic Gas Shutoff Valve will automatically stop the flow of gas to your home in the event of an earthquake. It meets all codes and can be easily re-set. It's recommended that a professional plumber be called to re-set it.