I had a buried PVC drum with removable lid, as an earthquake prep when I lived in Californication. Food, medical pack, 12ga. with ammo, cash, and camping gear. A propane stove, fuel, and a change of clothes, and a jacket. Might do another one for my hunting property. Food for thought.
One thing he dosen't mention but folks in southern Louisiana can tell you... make sure of your water table... you don't want it to rain and have your caches floating down stream with all the caskets...