Okay I'm not crazy . . .

. . . there really was an earthquake.  It felt very similar to when a helicopter or Osprey would fly right over the house back when we lived in North Carolina right next to the flight line - I could feel the slight vibration and the dishes in the cupboards rattled just a bit.  It was a little disconcerting simply because there was no sound associated with it.  If it was an aircraft or a weapon there would have been some sort of sound accompanied by the shaking feeling.