I assume everyone in the New York/New Jersey/eastern PA/maybe northern Delaware area just felt their buildings shaking.

That was a 4.8 magnitude earthquake originating near Lebanon, NJ (a ways west of Edison). You can look at the details from the US government's earthquake tracking website.

I've never felt an earthquake before, so that was something. I thought the people above me had turned on a motorcycle or something. I had no clue what could shake the building like that. Then it dawned on me. Not the place you expect these things. (I'm sure the Californians find this cute!)