The magnitude-5.8 quake, which some people initially feared was a terrorist attack, caused no known deaths or serious injuries.
Engineers have been studying cracks in the Washington Monument, and some federal office buildings are shut.
The quake centred on the state of Virginia but was felt widely.
It was one of the most powerful tremors to hit the US east coast since 1897.
High-rise frightThe quake shook Washington DC for about 30 seconds at lunchtime on Tuesday, with the White House, Pentagon and Capitol buildings among sites evacuated across the city.
Engineers are evaluating cracks found in the Washington Monument In New York City, the tremor sent many people fleeing high-rises such as the Empire State Building.
"I ran down all 60 flights," accounting office worker Caitlin Trupiano said. "I wasn't waiting for the elevator."
One of the most damaged buildings in the US capital was Washington's century-old National Cathedral: three capstones broke off and cracks appeared in some walls.
Pictures posted on the cathedral's website showed the extent of the damage, including fallen statues.
"Experts are tirelessly working to assess the building damage, both structurally and aesthetically," the cathedral managers said.
At the Washington Monument, the obelisk-shaped memorial to America's first president, engineers discovered cracks in the stones at the top.
They are evaluating how to repair the monument so it can be reopened to tourists.
Just two days after the start of the academic year, 126 Washington school buildings were closed on Wednesday.
Poking funDC Public Schools Chancellor Kaya Henderson said the sites were being examined by structural engineers.
The quake epicentre was near the Virginia town of Mineral, population 430 A handful of federal buildings were also shut on Wednesday, including some offices of the homeland security, agriculture and interior departments.
Some residents of apartments in the Washington DC suburbs were staying in shelters awaiting structural surveys at those buildings.
Two nuclear reactors were taken offline as a precaution near the epicentre of the quake, but no damage was reported.
The fuss generated by the relatively mild tremor has prompted some teasing, not least over on the west coast in California, where such events are much more common.
Images of toppled lawn chairs and wonky picture frames were posted on social networks.
The earthquake that devastated Japan in March released 60,000 times more energy than Tuesday's in the US.
It struck some 84 miles (135km) south-west of Washington, at a depth of 3.7 miles.
The epicentre was near the town of Mineral, in the state of Virginia, the US Geological Survey said.
Three aftershocks were recorded on Tuesday, measuring from 2.2 to 4.8 in magnitude.
Police released an undated image of Matthias Schepp The father of two missing Swiss twin girls trawled websites on suicide, guns and poison before killing himself, police say.
Friday 28 January: Schepp picks up his daughters to spend the weekend with them in their home village, St Sulpice, where both he and his estranged wife have homesSunday 30 January at 1300 (1200 GMT): The girls are last seen with Schepp in St SulpiceSunday 30 January at 1804 (1704 GMT): Schepp crosses the border into FranceMonday 31 January: Schepp sends a despairing postcard to his wife from Marseille; he and the girls take an evening ferry to Propriano, Corsica Tuesday 1 February: Schepp disembarks in Propriano, with or without the girls; he later leaves Corsica for Naples in ItalyThursday 3 February: Schepp throws himself under a train at Cerignola, in the south Italian region of Puglia The 43-year-old father had been looking after the girls for the weekend, but failed to return them home as planned.