During the commentary in the Japan earthquake, there was an article which said that along the coast of japan there were ancient stone markers, and the custom was that one should not build a house nearer the sea than the marker. Most people were not too sure why and over time ignored the markers. Now we see the result. Perhaps if they had listened to the wisdom of the people there before, who had noted how high the water rose and put a marker there to signify the safer areas, not so many people would have died.
I am not advocating moving the entire population of California. I am saying that people who build RIGHT ON TOP of the fault lines, or RIGHT BY THE SHORE in tsunami prone areas, or ON THE SLOPES of active volcanoes, are pretty dumb and such behaviour should not be encouraged. It's hardly half the world. It's common sense.