Firearms instructor and survivalist Colonel Jeff Cooper wrote on hardening retreats against small arms fire. In an article titled "Notes on Tactical Residential Architecture" in Issue #30 of P.S. Letter (April 1982), Cooper suggested using the "Vauban Principle", whereby projecting bastion corners would prevent miscreants from being able to approach a retreat's exterior walls in any blind spots. Corners with this simplified implementation of a Vauban Star are now called "Cooper Corners" by James Wesley Rawles, in honor of Jeff Cooper. Depending on the size of the group needing shelter, design elements of traditional European castle architecture, as well as Chinese Fujian Tulou and Mexican walled courtyard houses, have been suggested for survival retreats.
Earthquakes, tornadoes, and hurricanes can cause you to leave your home or even be trapped there. Roads could be blocked due to fallen trees, power lines, or even damaged earth from the natural disaster. Rescue crews can not be in all places at once. You may have to wait it out for quite a while before its over. You won't be able to go to the store or to the corner market.