If there is a eminent threat of fire and you are forced to evacuate, turn off you gas service. With your electrical service look (and smell) for signs of smoke. You may hear a "arcing" or "crackling" sound behind walls, near fixtures, etc. This is of particular danger because electrical fires can start and smolder behind walls for long periods of time before a full ignition happens. Definitely turn off the electrical service if you become aware of the aforementioned signs.
In all cases, If you are ever in doubt, shut you utility(s) off. Seek a professional evaluation before reconnecting. The information provided above is just a quick overview and should not be considered diffinative, exhaustive, or even accurate in all situations. On this topic, it is always best to seek and follow information from your utility service providers.
This is the perfect time to "Walk the Block."
Go house-to-house identifying the location of each home's utility shutoffs. That means water, gas, and electric utilities. Give each person a chance to turn the water and gas off (just briefly so pilot lights stay on). Some neighborhoods have been clever and produced a small map showing where each home's utilities are located. In the event of a disaster such as an earthquake, don't automatically shut off the utilities. Asses the situation, look for leaking water, if you don't see any signs of water flow, leave the water on. Gas has a similar requirement. Since gas has a very distinctive odor, that may be your first sign of a leak. If you do smell gas, IMMEDIATELY turn off the service. Also listen for a small "Hissing" noise that could indicate a gas leak.