At least in NYC, buildings have been constructed with earthquakes in mind. If you look at the Manhattan skyline, you'll see that all the skyscrapers are clustered way downtown, close to the southern end, and in midtown. That's because that is where buildings can be constructed directly on bedrock. When an earthquake hits, buildings and bedrock will vibrate together, and won't collapse. Don't forget, while they are very rare compared to the west coast, they can happen here...minor ones happen all the time. But sometimes they are major-one of the most devastating earthquakes in US history was on the east coast- Charleston, SC. And the New Madrid earthquake in the earlier 1800's redirected the Mississippi river!