MINERAL, Va. — Tens of millions of people from Georgia to Canada were jolted Tuesday by the strongest earthquake to strike the East Coast since World War II. Three weeks before the 10th anniversary of Sept. 11, office workers poured out of New York skyscrapers and the Pentagon, relieved it was nothing more sinister than an act of nature.
There were no known deaths or serious injuries, but cracks appeared in the National Cathedral and three capstones broke off its tower. Windows shattered and grocery stores were wrecked in Virginia, where the quake was centered. The White House and Capitol were partly evacuated.
The U.S. Geological Survey said the quake registered magnitude 5.8. By West Coast standards, that is mild. But the East Coast is not accustomed to earthquakes at all, and this one unsettled some of the nation's biggest population centers.
In New York and Washington, people said their thoughts were of an explosion or terrorist attack. In some cases, workers in Washington mentioned the temblors in phone calls to colleagues in New York, and seconds later, the shaking reached there, too.
"We thought it was a bomb at first because everyone has 9/11 on the brain and that it's so close to September and the 10th anniversary," said Cathy McDonald, who works in an IRS office in downtown Washington.
In New York City, hundreds spilled out of the federal courthouse blocks from ground zero after the quake struck at 1:51 p.m. Workers in the Empire State Building rushed into the streets.
"I thought we'd been hit by an airplane," said one worker, Marty Wiesner.
Adrian Ollivierre, an accountant who was in his office on the 60th floor when the shaking began, said: "I thought I was having maybe a heart attack, and I saw everybody running. 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."
The quake was felt as far north as Toronto, as far west as Indiana and Kentucky and as far south as Atlanta and Savannah, Ga.
The White House said there were no reports of major damage to the nation's infrastructure, including airports and nuclear facilities. Two nuclear reactors at the North Anna Power Station in Virginia were automatically taken off line by safety systems, said Roger Hannah, a spokesman for the U.S. Nuclear Regulatory Commission. The plant is in the same county as the quake's epicenter, about 80 miles southwest of Washington and 40 miles northwest of Richmond, Va.
The Park Service closed all monuments and memorials on the National Mall, and ceiling tiles fell at Reagan National Airport outside Washington. The Capitol was reopened by late afternoon for people to retrieve their things.
Engineers were working to make sure the Washington Monument survived the earthquake. Park officials said the top of the 555-foot-tall stone obelisk appears to have cracks, and it would remain closed pending a top-to-bottom inspection.
At the Pentagon, a low rumbling built until the building itself was shaking, and people ran into the corridors of the complex. The main damage to the building, the largest single workspace for the federal government, came from a broken water pipe.
Officials at the National Cathedral said the building sustained "significant damage," with three capstones, each shaped like a fleur-de-lis, breaking off the main tower. Cracks appeared in the flying buttresses around the apse at the cathedral's east end, the oldest part of the building.
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 crumbled, and there were stores with shelf contents strewn on the floor. Several display windows at businesses 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.
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 have been a few aftershocks. Two were magnitudes 2.2 and 2.8, but a later one measured 4.8.
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.