Earthquake or a really heavy machine?

I was working on a COW on the 13th floor of the tower at BGH this afternoon. The floor started to shake, and the nurses around me started asking each other what that was, and an X-ray tech that happened to be rolling a portable x-ray machine said it was just his machine. We were like it feels a bit different than that. Then people started saying that it could have been an earthquake. That is what I kept hearing as I was walking back to my office. When I got to my office, I checked and sure enough, there was a 5.5 earthquake in Canada. http://earthquake.usgs.gov/earthquakes/eqarchives/last_event/world/world_canada.php They just sent out a system wide email, two hours after the fact, stating that there was a confirmed earthquake, but no damage reported in any of the facilities or Western NY.