Another consideration is that the initial mega-quake will be followed by lots of aftershocks -- some of them major quakes.

Whether the situation will warrant staying with the truck or hoofing it, I'd be wanting a good size and comfortable backpack full of the gear-supplies we discuss here constantly.

And comfortable hiking boots and extra socks. And cash.

Do you currently carry that stuff on a routine basis?

A brisk walking pace would be 3mph.

You're going to want constant access to news reports to guide your decisions -- so a portable AM-FM radio and extra batteries should be part of the mix. It would save running your car battery down.

If the local radio stations are knocked out, be on the lookout for a vehicle that may have satellite radio. It will be important to know the epicenter and magnitude of the quake.

I'm guessing I'd want to stay with my vehicle unless and until it was absolutely necessary to abandon it. Especially in the winter. If there's a major quake then emergency services will soon be checking out I-5 -- helicopters will be flying over in short order -- and they'll be very eager to restore that major transportation route to some degree of functionality -- including punching through guardrails if necessary.