Washington ? Earthquakes are so rare in the Washington area that even a geology student wasn’t quite sure what was going on when a minor one hit early Friday. Was it a truck passing by? A low-flying plane?

Gerasimos Michalitsianos, who will be a senior at the University of Maryland, College Park, was sitting on his couch looking at e-mails when the 3.6-magnitude temblor occurred.

It was the strongest to hit within 30 miles of D.C. since officials began keeping records in 1974.

Washington area residents are used to politicians being the region’s movers and shakers, so it was a surprise when the earth below shook. The earthquake rattled windows and jostled dishes but apparently caused no serious damage. President Barack Obama told reporters he didn’t feel it.