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!)

Dude actually made this tweet on 3rd February, two days before the dreaded quake hit Turkey:

Sooner or later there will be a ~M 7.5 #earthquake in this region (South-Central Turkey, Jordan, Syria, Lebanon). #deprem

What's interesting about this researcher is that he doesn't study earthquakes through the traditional or established way of Seismology. Instead, his institute, SSGEOS specializes in "monitoring geometry between celestial bodies related to seismic activity". It's incredible how little we know about the world we live in and how much more there is to know yet.