Should I buy a first aid kit or make my own, if I live in earthquake country?

Your choice but. Cheaper to make your own. Here are some good links on the subject: http://bit.Ly/lqrlfh and http://bit.Ly/lqroke and http://bit.Ly/lqrqc6.
Earthquake - NZ. Getting ready before an earthquake strikes will help reduce damage to your home and business and help you survive. http://www.getthru.govt.nz/disasters/earthquake/