Post Now - Earthquake in Maryland felt across area A 3.6 magnitude earthquake rattled the Washington area early Friday, with thousands of residents reporting that they felt the ground shake as they slept or were waking. The U.S. Geological Survey said the quake was centered in Montgomery County and struck at 5:04 a.m. "The whole house shook," said Carroll Ripley, of Germantown. "I thought maybe there was an explosion or a plane flew over the house or something." "I went straight outside to do a perimeter check -- in my underwear," he said. The epicenter was in the Germantown-Gaithersburg area near I-270 and Route 119 (39.167Â°N, 77.252Â°W), according to USGS. It was 3.1 miles deep.