I was a paramedic on the Oregon coast and part of a community Cascadia preparation board for the county I lived in.

As an individual, the best thing you can do is have a go bag you can carry and several planned evacuation routes from most likely places you will be. Plan these with the expectation that bridges will fail, traffic will clog, nearby dams will break, old building may fall and electricity will be out including possible fires.

Additionally, in a large scale event. Help will not be coming for you. Local teams only and that's a wish. Expect to be on your own, literally you and the people you find face to face, for 3-6 weeks. Plan accordingly for your worst seasonal weathers. Know where the clean reliable water sources will be, food pantries, farms, and have a weapon and medicine if possible. Some sort of tools to manage debris is good.

That's a good preplan in a tiny nutshell form. Band together.

If you have hours, that's lucky. 30 mins is a possible scenario. So know that. If hours, and no go bag, throw layers, something waterproof, some non perishables, any medications and a hammer and role of duck tape along with a gallon of water and some bleach. Lighter, tent, knife, a flashlight, radio if you can etc. but don't spend more than 10 mins and drive to the nearest high ground you get to. Of you get blocked. Pull your vehicle off the road, leave it unlocked and a path on the road if you can. Then start jogging up in elevation. Don't stop.

Clench your butt checks and pray.

But make a detailed plan now instead

I could go way deeper into this but that my from the hip dirty action plan. Really it's a very individualized and circumstantial strategy based on your area, your needs, and your location at the time of the quake plus time of the first wave break