I like your thinking but playing devils advocate... if your second home is only 10 miles away... wouldn't the earthquake have most likely damaged that place as well? Do you have a 3rd option to dwell if option 2 is also damaged?
Good point. The 2nd site has enough land that even if the structure collapses, we could camp out on the land. Plus, it's hard-ish to find, more defendable. There is a 3rd option, but it's pretty far (assumption that if the earthquake is that bad, we need to leave SoCal).