Here's the best bit of "preparedness": say 'hello' to your neighbors!
Many places have suffered major disasters, and have had minimal disruption, followed by a rapid return to 'normal.' Those places had folks who didn't have to be told to work together, and to look out for each other.
Other places have needed as little as a rumor of a court verdict- and the fires started, the riot began, and the looting was on. I know one such place that hasn't recovered yet from its' 1968 frenzy.
