You will notice a lack of water before you notice much else, especially if the weather is hot during the earthquake, or you are particularly susceptible to stress, as worrying can dehydrate you. Set aside four or five gallons for everyone in your home, and budget for a gallon per person in consumption each day. Also, pack four or five days of nonperishable food for each person in your home. Because much nonperishable food comes in cans, you'll want a manual can opener as well.
You can never have too many batteries and you'll want a flashlight for each person in your home. Don't rely on the expiration dates on your battery packaging; test your flashlights every six months, and keep spare batteries near your flashlights. You'll also want a box of matches and some candles, to give you light at night if the power is still out.
Because of the many injuries that can happen during an earthquake, the list of first aid items to have on hand is considerable, as there is also the possibility of extended exposure to the elements to consider. You'll want an extra supply of any maintenance prescriptions for people in your home. Also, bug repellent, hydrogen peroxide, anti-diarrhea medicines, antibiotic spray or ointment, and drops for your ears, eyes and nose. You'll also want a supply of bandages, ranging from small latex bandages to larger wraps and gauze pads, as well as butterfly bandages. Have a kerchief on hand for a sling and a splint kit as well.
If there's no power, you won't be able to use an ATM, and you won't be able to use your debit or credit card. Have enough cash on hand for a week of necessities, as well as your government issued identification. Keep your passport somewhere easy to remember and find. Put all of your identification documents into a money belt you can wear inside your clothes, if needed, and keep cash and credit cards in there as well.