People are very, very bad at understanding probability and the math behind it. They don't grasp what this means. So let's put it another way:
If the forecast called for a 62% chance of thunderstorms tomorrow, would you take an umbrella with you?You should. And likewise, all of us who live in the Bay Area need to be prepared for a major disaster on a daily basis. But most of us aren't.
Fortunately, I have some friends who recently held an "Armageddon Night", where we got together and talked about how to prepare for this stuff. We had someone from FEMA come and talk, and some presentations and discussions on earthquake preparedness.
Since then, I've started making real preparations. Flashlights and radios that don't need batteries. Extra food. First aid kits. Water. A "go bag" stashed in my car. I just need to get some important papers copied and I should be as set as I can be.
If you live in the Bay Area, you should make sure you're prepared, too. It's yet another thing to deal with. But having lived through the Northridge quake in Los Angeles, I know first-hand how much life can be disrupted by even a modest interruption in services.
The last time the power was out, how much were you annoyed? Inconvenienced? OK. Now the power is out. The water is out. The gas is out. The phone may be out. For several days.
The only thing you can do is to act now. So do it. And read Nassim Nicholas Taleb's "Fooled By Randomness".