The National Cathedral said its central tower and three of its four corner spires were damaged, but the White House said advisers had told President Barack Obama there were no reports of major damage to the nation's infrastructure, including airports and nuclear facilities.
The U.S. Geological Survey said the quake registered magnitude 5.8 and was centered 90 miles southwest of Washington. It was mild by West Coast standards, but the East Coast is not used to quakes of any size, and this one briefly raised fears of a terror attack less than three weeks before the 10th anniversary of Sept. 11.
"I thought I was having maybe a heart attack, and I saw everybody running," said Adrian Ollivierre, an accountant who was in his office on the 60th floor of the Empire State Building when the shaking began. "I think what it is, is the paranoia that happens from 9/11, and that's why I'm still out here - because, I'm sorry, I'm not playing with my life."
Two nuclear reactors at the North Anna Power Station, in the same county as the epicenter, were automatically taken off line by safety systems, said Roger Hannah, a spokesman for the U.S. Nuclear Regulatory Commission.
At the Pentagon, a low rumbling built until the building itself was shaking, and people ran into the corridors of the complex. The shaking continued there, to shouts of "Evacuate! Evacuate!" The main damage to the building, the largest single workspace for the federal government, came from a broken water pipe.
The Park Service closed all monuments and memorials on the National Mall, and ceiling tiles fell at Reagan National Airport outside Washington. Many nonessential workers in Washington were sent home for the day. The Capitol was reopened by late afternoon for people to retrieve their things.
The National Cathedral said cracks had appeared in the flying buttresses around the apse at one end. "Everyone here is safe," the cathedral said on its official Twitter feed. "Please pray for the Cathedral as there has been some damage."
In lower Manhattan, the 26-story federal courthouse, blocks from ground zero of the Sept. 11 attacks, began swaying, and hundreds of people streamed out of the building.
The New York police commissioner, Raymond Kelly, was in a meeting with top deputies planning security for the upcoming anniversary when the shaking started. Workers in the Empire State Building spilled into the streets, some having descended dozens of flights of stairs.
"I thought we'd been hit by an airplane," said one worker, Marty Wiesner.
New York District Attorney Cyrus R. Vance was starting a news conference about the dismissal of the sexual assault case against Dominique Strauss-Kahn, the former head of the International Monetary Fund, when the shaking began. Reporters and aides began rushing out the door until it became clear it was subsiding.
On Wall Street, the floor of the New York Stock Exchange did not shake, officials said, but the Dow Jones industrial average sank 60 points soon after the quake struck. The Dow began rising again a half-hour later and finished the day up 322 points.
Shaking was felt as far south as Charleston, S.C., as far north as Maine and as far west as Cincinnati and Atlanta. It was also felt on Martha's Vineyard, off the coast of Massachusetts, where Obama is taking summer vacation and was starting a round of golf when the quake struck at 1:51 p.m. EDT.
Obama led a conference call Tuesday afternoon on the earthquake with top administration officials, including his homeland security secretary, national security adviser and administrator of the Federal Emergency Management Agency.
Around Mineral, Va., a small town close to the epicenter, people milled around in their lawns, on sidewalks and parking lots, still rattled and leery of re-entering buildings. All over town, masonry was crumpled, and there were stores with shelved contents strewn on the floor. Several display windows at businesses in the tiny heart of downtown were broken and lay in jagged shards.
Carmen Bonano, who has a 1-year-old granddaughter, sat on the porch of her family's white-frame house, its twin brick chimneys destroyed. Her voice still quavered with fear.
"The fridge came down off the wall and things started falling. I just pushed the refrigerator out of the way, grabbed the baby and ran," she said.
By the standards of the West Coast, where earthquakes are much more common, the Virginia quake was mild. Since 1900, there have been 50 quakes of magnitude 5.8 or greater in California alone. Quakes in the East tend to be felt across a much broader area.
"The waves are able to reverberate and travel pretty happily out for miles," said U.S. Geological Survey seismologist Susan Hough.
The Geological Survey put the quake in its yellow alert category, meaning there was potential for local damage but relatively little economic damage.
The agency said the quake was 3.7 miles beneath the surface, but scientists said they may never be able to map the exact fault. Aftershocks may help to outline it, said Rowena Lohman, a seismologist at Cornell University. There were at least two aftershocks, magnitudes 2.2 and 2.8.
The last quake of equal power to strike the East Coast was in New York in 1944. The largest East Coast quake on record was a 7.3 that hit South Carolina in 1886. In 1897, a magnitude-5.9 quake was recorded at Giles County, Va., the largest on record in that state.
A 5.8-magnitude quake releases as much energy as almost eight kilotons of TNT, about half the power of the atomic bomb dropped on Hiroshima, Japan. The earthquake that devastated Japan earlier this year released more than 60,000 times as much energy as Tuesday's.
The Virginia quake came a day after an earthquake in Colorado toppled groceries off shelves and caused minor damage to homes in the southern part of the state and in northern New Mexico. No injuries were reported as aftershocks continued Tuesday.
On the East Coast, Amtrak said its trains along the Northeast Corridor between Baltimore and Washington were operating at reduced speeds and crews were inspecting stations and railroad infrastructure before returning to normal.
In Charleston, W.Va., hundreds of workers left the state Capitol building and employees at other downtown office buildings were asked to leave temporarily.
"The whole building shook," said Jennifer Bundy, a spokeswoman for the state Supreme Court. "You could feel two different shakes. Everybody just kind of came out on their own."
In Ohio, office buildings swayed in Columbus and Cincinnati, and the press box at Progressive Field, home of the Cleveland Indians, shook. At least one building near the Statehouse was evacuated in downtown Columbus.
In downtown Baltimore, the quake sent office workers into the streets, where lamp posts swayed slightly as they called family and friends to check in.
John Gurlach, air traffic controller at the Morgantown Municipal Airport in West Virginia, was in a 40-foot-tall tower when the earth trembled.
"There were two of us looking at each other saying, `What's that?"' he said, even as a commuter plane was landing. "It was noticeably shaking. It felt like a B-52 unloading."
Immediately, the phone rang from the nearest airport in Clarksburg, and a computer began spitting out green strips of paper - alerts from other airports in New York and Washington issuing ground stops "due to earthquake."
The earthquake caused a stir online, where people posted to Facebook and Twitter within seconds and described what they had felt. The keywords in posts, or hashtags, included "DCquake," "VAquake" and "Columbusquake," an indication of how broadly the quake was experienced.
"People pouring out of buildings and onto the sidewalks and Into Farragut Park in downtown DC," Kevin Madden, a Republican strategist, posted on Twitter.
Quake photos and videos also made the rounds. A handful were authentic. Many more were not - they were favorite earthquake scenes from Hollywood blockbusters or footage of people shaking their glasses and plates at an Olive Garden.
The following Associated Press writers contributed to this report: Larry Neumeister, Tom Hays, Adam Geller and Eric Carvin in New York; Lolita C. Baldor and Seth Borenstein in Washington; Alicia Chang in Los Angeles; Ray Henry in Atlanta; Tom Withers in Cleveland; JoAnne Viviano in Columbus, Ohio; and Vicki Smith in Morgantown, W.Va.