Two things popped into my head:

1) Communications: assume phones (cell & landline) are out: how far away is everyone? Shouting distance? What about radios? What kind, what freqs to use? etc. etc. etc. Someone might to call the community to help get someone who is trapped---they need a way to alert everyone.

2) A roster of who and how many and ages live where. Our HOA publishes a list of who lives where and kids and ages in each home. In an earthquake aftermath, you might want to do a headcount and know who is OK, and who is missing, and possibly trapped. To do that, you need to know (at least on a general basis) who lives in the community.