If I know it's going to hit, I can probably figure out where. So Step One is to do that, and use it to inform Step Two. Step Two is to find a tectonically stable place away from the coast to put my shelter. Step Three is to build and stock the best underground shelter I can afford after selling everything I can and maxing out my (excellent) credit.

Realistically, if I know, a lot of people know, so this kind of plan is less likely to succeed. I might be better off banding together with others to build and stock the shelter.