Actually, I'm not sure that's totally true. I witnessed a burst steam main, very similar to the Grand Central one, up in the Upper East Side, and there are no skyscrapers in that immediate area. The steam cloud easily shot up above the surrounding brownstones and sounded just like a jet engine. I couldn't hear myself yelling and I was a couple blocks (short blocks, not the long avenue blocks) away. Anyway, I'm just saying that it's hard to know where there are and aren't steam mains.

I felt a tiny earthquake once in NYC. I recall that the epicenter was actually in the Upper East Side. We eat earthquakes here in California for breakfast, but in NYC, with all those really old unreinforced masonry buildings, a good 5.0 could bring a lot of buildings down. Despite regular inspections, you see buildings lose their brick facades from time to time, too. Imagine walking down the street on the sidewalk and all the buildings are shedding their brick facades down on your head during an earthquake!