In an effort to keep this thread 'on topic', since it is about 'relatively safe housing', take a look at the monolithic domes.
These are structures that will survive earthquakes - in tact. no 'relatively safe' needs to be applied to these. They will also survive tornadoes, fires, hurricanes, etc.
Their strength comes from their shape - a dome.
http://www.monolithic.com/
I won't post photos of monolithic domes - I'll leave that to the experts here. I will also state that they keep very warm in the winters, and cool in the summers.
One family that has a dome in Alaska (I believe it was in Alaska), was going through the winter, and ran out of propane for heating. Only... they didn't know about it until two days later, as the warmth inside was adequate.
Another monolithic home owner in Kansas went through a tornado - which did a dance on top of the dome, before it went away to carry on its' massive destruction. (There was a pock mark on the exterior where the tornado struck the dome).
Domes along the Florida coast have survived hurricanes.
Domes in California have survived fires that have decimated entire forests and other homes.
Gary, an employee at Monolithic even took a rifle and fired it at a monolithic dome (kiddies, don't try this at home), at almost point blank range. It did not penetrate the shell, and only went through the foam and stopped at the concrete layer.
Personally - I don't want to live in a home that is 'relatively safe', I want to live in a home that is DEFINITELY safe.
But - to each their own.
Regards,
Jim TX