A small 3.6 magnitude earthquake shook the Washington area on Friday morning, but there were no reports of injuries or damage in a region not usually associated with quakes.
The temblor struck about 5:04 a.m (0904 GMT), waking many people in the District of Columbia and suburban Maryland and Virginia. It was centered near Germantown, Maryland, about 20 miles (32 km) northwest of the U.S. capital, at a depth of 3 miles (5 km), the U.S. Geological Survey said.
USGS geophysicist Randy Baldwin said he had not heard any reports of damage, "but it was obviously widely felt throughout that region."
Baldwin said small quakes occurred in the region every few years, although there was no history of larger, damaging earthquakes in Washington. The last quake in the area -- a 2.0 magnitude -- occurred in May 2008.
The USGS said there was no record of an earthquake centered within the District of Columbia, but that vibrations from quakes in seismic regions such as the St. Lawrence River Valley, Missouri, Ohio and Virginia had been felt by Washington residents over the years.
A March 1828 earthquake was felt across several Eastern states and reported as "violent" in Washington and Baltimore, the USGS said.
John Quincy Adams, then U.S. president, wrote in a March 9, 1828, diary entry from the White House: "There was this evening the shock of an earthquake, the first which I ever distinctly noticed at the moment when it happened," according to the agency's website.
"I was writing in this book, when the table began to shake under my hand and the floor under my feet. The window shutters rattled as if shaken by the wind, and there was a momentary sensation as of the heaving of a ship on the waves," Adams wrote.
"It continued about two minutes, then ceased. It was about eleven at night. I immediately left writing, and went to my bedchamber, where my wife was in bed, much alarmed."