I hate being such a paranoid... I'm in my apartment, went suddenly I feel slight vibrations. Naturally I quickly become nervous, which means I shake slightly and can't tell if the vibrations are continuing or not. I turn off my fan; still feel vibrations. Obviously my immediate thought is that these tremors mean an earthquake is imminent (even though the one earthquake I've been in started suddenly without warning), so I freak out, shove all my stuff into my bag and run down the stairs and off to the lab building earlier than I usually would. (The lab building is much newer than my apartment building, and is designed to resist vibrations)

As I pass out the door of my building, I realize that they're doing construction on the retail space at the ground floor, and that's what the vibrations were coming from