For a time in the 1970s, the terms survivalist and retreater were used interchangeably. While the term retreater eventually fell into disuse, many who subscribed to it saw retreating as the more rational approach to conflict-avoidance and remote "invisibility". Survivalism, on the other hand, tended to take on a more media-sensationalized, combative, "shoot-it-out-with-the-looters" image.
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.