I think that everything EAST of the San Andreas will fall away into...ummm...

Besides, on the other side of the Atlantic, in the Canary Islands, there's this volcano which might erupt and knock half an island into the water and send a tidal wave toward the East coast.
Whether this happen before or after Yellowstone erupts and blows away the center of the country, we don't know...but it will make little difference, 'cause global warming will make everything south of Omaha too hot to live in..............and there are asteroids whizzing about to knock off the survivors.

Oh, did I mention the increased tornados, hurricanes and the continued march of the killer bees?

I'm heading for ....ummmm... the Yukon!