A magnitude-5.8 quake centered in Virginia rocked the East Coast, with tremors felt as far south as North Carolina, as far north as Buffalo and Boston, and as far west as Detroit.

Did you feel the tremors? Share your stories and photos with our reporters at debrown@usatoday.com.

Update at 7:36 p.m. ET: Think all earthquake-jaded Left Coasters are laughing at Right Coasters' jitters?

"Well, Easterners, don't believe it. When it comes to quakes, no one gets used to them, especially not when they're in the magnitude 5.0-plus range," a Los Angeles Times writer confesses.

"The truth is, what most of us on the West Coast were thinking is, Thank God it wasn't us this time."

Read the rest here, Eastern quake veterans.

Update at 7:11 p.m. ET: Readers from up and down the Eastern Seaboard and Canada have been sharing their quake experiences, and USA TODAY's reader advocate, Desair Brown, has complied some of the many e-mails she has received. Here are a few:

Atlanta, Ga. One of my team members came over to me and asked me if I felt the building shake a moment ago? I told her no I hadn't and that it must be an A/C unit going on. Then another employee approached both of us and asked if we felt the building move. Again, I said I hadn't because I was walking around and perhaps didn't catch the movement. By the time we finished talking, my entire staff was in the bullpen area talking about the entire building shaking and that it couldn't have been an A/C unit. I went online to the Georgia Tech web site for seismic activity and sure enough, there was activity on the waveform! Kurt Blumthal Birmingham, Mich. Just before 2 p.m. today, I was in my car at an ATM machine and I felt my car shake. I'd never felt that sort of sensation before and was upset, because it's a new car and I was worried that something was wrong with the engine. I even looked at the dashboard to see if the engine had a warning signal that it might be overheating. It lasted less than a minute - maybe 30 seconds - and then it stopped. Terry Matlen West Mifflin, Pa. The couch on which I was sitting shook for about 10 seconds. I thought, "Must have the house checked for termites." Fifteen minutes later a friend called from D.C., about the quake. I told him I had felt it and asked if P.A. had been mentioned. He said "No, call it in to CNN." I did. But, I only said I was calling from P.A. So, now the news says it was felt in Philadelphia! Julia Moore Louisa, Va. Dishes shattered on our kitchen floor and things fell from the shelves. The house is in total disarray. I stood on my front porch with another woman who was home alone, and the ground shook once more. Apparently a 2.8 aftershock took place about an hour after the initial quake took place. It shook our homes again. It's 5:10 p.m. now, about three hours after and Louisa, Va., still has rumblings from beneath the ground. Jackie Clark Brooklyn, N.Y. I was attending a GoToMeeting from a conference room in my office at Sunset Park, Brooklyn, N.Y., led by our vendor located in Virginia Beach. She felt it first, of course, telling us her house was shaking and we all said how weird. Within literally not more than a minute, we started shaking, too. The conference call dropped, and we deliberated climbing under the table when the fire alarm system instructed us to evacuate. Fortunately, everyone is fine, with the possible exception of our vendor's AC unit. Toby Nemiroff Toronto, Canada While my boss was on an important call the phone cut out. When he called back the person on the other line, near Washington, D.C., had informed us that there had just been an earthquake. Not even 60 seconds later as I was sitting at my desk, I started to feel very dizzy and queasy, like I might faint, when I looked over to see the juice in my clear cup swaying quite significantly back and forth. I turned to my coworkers and asked if they felt what it was, and sure enough we all thought we were crazy. Molly MacDonald Raleigh, N.C. I thought my son Ryan was rolling the barbecue grill around the back porch for some reason. But then it increased and I thought, "WHAT is that young man DOING?!?" Next, small glass objects in a cabinet started to rattle and I thought "Could this ACTUALLY be an earthquake?" Then my son ran into the room and I KNEW it wasn't him. Dan Finch Columbus, Ind. I was sitting at my desk in Columbus, Ind., when I began swaying slightly back and forth in my chair. I did not think much of it until other in the office started noticing it as well. It lasted about 30-45 seconds. You could actually feel the floor shaking slightly as well. Not bad enough to cause any damage though. Phil Leahigh

Update at 6:48 p.m. ET: USA TODAY's Marisol Bello is at the epicenter of today's quake, Mineral, Va., and reports isolated damage to some homes, businesses and cars hit by falling bricks.

She is at the local fire house and rescue squad, where residents have gathered to make sandwiches for firefighters or other residents who may be displaced.

"I thought it was a runaway train," said Marilyn Gutekenst, 59, a substitute teacher and chaplain for the rescue squad who was clearing dishes on her back desk after a lunch with friends. "I thought, 'I don't belong here. I need to move quickly.' "

She said she ran inside her home --near the train tracks -- to see picture frames falling off the wall, plates breaking and bookcases toppling. The house looked structurally OK, however, so she and her husband, Albert, 65, a retired second lieutenant with the rescue squad, headed to the firehouse to help.

Update at 6:36 p.m. ET: The New York Times notes that after the Capitol was evacuated, the Senate held an unusual, 22-second session in a basement conference room in the nearby Postal Square Building, one structure designated for use in an emergency.

The Times writes that the session "essentially served as a dry run for procedures put in place after the Sept. 11 attacks."

Details here.

Update at 6:28 p.m. ET: The quake snapped a water pipe and flooded parts of two floors of the world's largest office building, otherwise known as the Pentagon, USA TODAY's Tom Vanden Brook reports. The building was partially evacuated and workers were allowed back in after Pentagon officials gave the all-clear.

Update at 6:11 p.m. ET: USA TODAY's Kitty Bean Yancey has more about the Washington Monument's alleged tilt.

Update at 5:46 p.m. ET: The U.S. Park Police have shot down a Fox News report that the Washington Monument was leaning as a result of the earthquake, TPM says.

Here's how The Washington Times reported the Fox report:

Fox News anchor Megyn Kelly reported at 2:30 p.m. ET their bureau received information from a producer saying that a Captiol Hill Police officer was saying the Washington Monument may actually be tilting as a result of the earthquake. Seismologist John Rundle joined Kelly on her show and confirmed that the Washington Monument could very well be tilting as a result of the earthquake and the structure should be checked out.

There are, however, conflicting reports at the moment about whether the monument suffered any damage. A Park Service spokesman told the Associated Press there was "absolutely no damage" to the Washington Monument, Lincoln Memorial or other tourist destinations along the Mall.

CNN later reported the quake had loosened some stones.

Here's an earlier CNN roundup of damage reports.

Update at 5:35 p.m. ET: Virginia Primary voting continues, USA TODAY's Carly Mallenbaum reports. The longest polling place closure was 30 minutes, which "was rare," according to a tweet from the Virginia State Board of Elections.

Update at 5:28 p.m. ET: USA TODAY's Jeff Stinson has a look at what's been happening with some transportation:

About 390 flights to or from New York City's JFK, Reagan National, Washington Dulles and New Jersey's Newark Liberty were delayed at least 30 minutes, five times more than usual, said Daniel Baker, chief executive officer of Houston-based data tracker FlightAware.com told Bloomberg News. Passenger terminals at Reagan National and Dulles remained open, with "no major damage that I'm aware of," Tara Hamilton, a spokeswoman for the Metropolitan Washington Airports Authority. And the FAA reported no air traffic control outages. The national passenger rail service Amtrak reported that it slowed the speed of trains between Baltimore and Washington following the quake. The quake snarled traffic in the nation's capital and delayed flights along the East Coast. Many traffic lights were knocked out in Washington, and the Washington Area Metropolitan Transit Authority ordered all subway and surface trains to reduce their speed to 15 mph until inspectors could check rails, which slowed the evening commute for many. More than 700,000 riders use Metro trains most workdays, although August is a slower month. The authority said buses on all major routes suffered delays in the late afternoon because many traffic signals were out and traffic was clogged. New York's MTA reported no major incidents or delays on subways or rails.

Update at 4:44 p.m. ET: The National Cathedral in northwest Washington sustained "significant damage," with capstones tumbling off three of the four spires on the central tower, a spokesman tells USA TODAY's Brad Heath.

Spokesman Richard Weinberg said the cathedral's tower is the highest point in Washington. Other stones shaken loose by the quake tumbled onto the grass outside.

There were about 200 people inside the cathedral at the time, Weinberg said. None was injured. He said that repairing the spires and other damage will "definitely involve a lot of work" but that the extent of the damage would not be known until the cathedral's stonemasons and engineers finished assessing the building. It remained closed this afternoon.

Update at 4:35 p.m. ET: The Federal Emergency Management Agency reports cellphone network "congestion" and asks people to use text or e-mail in the next few hours, except in emergencies.

Here are tips for what to do before and during a quake.

Update at 4:13 p.m. ET: USA TODAY's Gregory Korte reports some facts from seismological data shared with the USGS:

It registered, in varying degrees of intensity, as far west as St. Louis, Mo., as far south as Montgomery, Ala., and as far north as Easton, Maine.

Update at 4:05 p.m. ET: The U.S. Geological Survey has lowered the quake's magnitude to 5.8 from 5.9.

The quake was quite shallow, rupturing at a depth of about 3.7 miles, with a variation of +/- 1.6 miles.

By Douglas Stanglin

USA TODAY

Update at 3:36 p.m. ET: LaGuardia and JFK airports, which were shut down after the quake, have resumed service, MSNBC reports. The passenger rail service Amtrak reports that it is reducing the speed of trains between Baltimore and Washington after the quake.

Update at 3:28 p.m. ET: USA TODAY's Kevin Johnson, reporting from downtown Washington, says the quake knocked out traffic lights downtown, snarling traffic as fire trucks and other emergency vehicles -- sirens blaring -- snaked through the confusion. The sidewalks teemed with anxious office workers who fled or were ordered to leave their buildings.

At the Grand Hyatt Hotel, uniformed cooks, waiters, barristas and room maids poured onto 10th Street. Many of them had cellphones pressed to their ears and looked skyward as if concerned about the integrity of the hotel towering above. "I thought I was fainting or something with the ground moving like it was,'' said bellman Ted Mesfin, 54. "Flatscreen TVs and dressers were shaking in the (guest) rooms. People thought the whole building was coming down.''

Update at 3:21 p.m. ET: Federal officials say two nuclear reactors at the North Anna Power Station in Louisa County, Va., near the epicenter of the quake, were automatically taken off line by safety systems around the time it struck, the Associated Press reports.

The Dominion-operated power plant is being run off of four emergency diesel generators, which supply power for critical safety equipment.

Nuclear Regulatory Commission spokesman Roger Hannah says the agency was not immediately aware of any damage at nuclear power plants in the Southeast. The NRC and Dominion are sending people to inspect the site.

LIVE: Washington area coverage from WUSA

Update at 3:13 p.m. ET: Alesha Williams Boyd of the Asbury Park Press, took some soundings of people's reaction in her area and got this reaction: "I thought a cat was under my recliner," says Pat Dolan of Lakewood, N.J. "My chair was moving." The feeling was so odd Dolan woke her brother, who'd felt nothing and "thought I was crazy," Dolan says. "I insisted my chair was rocking side to side," Dolan said. "I thought it was cool but spooky."

Update at 3:08 p.m. ET: USA TODAY's Kevin McCoy, who was covering the Dominique Strauss-Kahn hearing in New York, says the quake hit just as Manhattan DA Cyrus Vance Jr. was starting a news conference. Police and court officers immediately evacuated the building.

Sonia Spence, a data transcriber for the U.S. Department of Citizenship and Immigration Services, says she had just returned to her desk on the fourth floor of 26 Federal Plaza when the building began to sway. "I thought, 'What could be shaking the building like this?' My first thought was a terrorist." Spence, a legally blind Bronx resident, said she dropped her purse which contained her cellphone, hurrying downstairs and outside.

Update at 3:06 p.m. ET: USA TODAY's Melanie Eversley reports that organizers for Sunday's planned dedication on the National Mall for the Martin Luther King Jr. National Memorial say the National Park Service is performing required safety checks and is monitoring the situation. They say nothing on the site has been disturbed.

Update at 3:04 p.m. ET: The State Department building in the Foggy Bottom area of Washington has been evacuated, public affairs specialist Urenia Young says in an e-mail. "We are out of the building," she writes

Update at 3:01 p.m. ET:

USA TODAY's Dan Vergano sent us this file:

"Central Virginia does get its share of minor earthquakes, but an earthquake of this size on the East Coast is certainly very unusual," says seismologist Karen Fischer of Brown University. Virginia is not on an active earthquake fault and is roughly in the middle of the North American continental crustal plate, she says. But it has residual fault scars left over from 200 million to 300 million years ago, when it was an earthquake zone, at the time when the Atlantic Ocean rifted apart from Europe. "We are just seeing pressure build up and release on those scars," Fischer says. "There is a lot of debate on exactly what is going on down there and exactly how quakes this big happen in this kind of crustal zone." Because the crust under the East Coast is colder and firmer than the West Coast, shocks travel more efficiently through it, accounting for the widely felt shaking. "One lesson of this quake is that building codes will likely need to be revisited on the East Coast," Fischer says. "Because we are not as conscious of earthquakes here as the West Coast, and we will have to see about structural damage to buildings, although I have not heard any damage reports so far."

Update at 2:53 p.m. ET: MSNBC reports that the quake has caused flight delays at a number of airports, including JFK, Newark, Washington National, Washington Dulles and Philadelphia.

Update at 2:51 p.m. ET: Verizon Wireless and AT&T say their networks were congested as the quake sent people scrambling for the phones, the Associated Press reports.

Verizon Wireless spokesman Tom Pica says there has been no damage to the company's equipment. He says the crush of phone calls made it hard for some customers to get through for about 20 minutes after the quake. That has since began to clear, he says. Sprint says some customers may experience delays.

Update at 2:48 p.m. ET: Halley Pack, 24, a paralegal, was putting on her sneakers in the basement-level gym of her office building in downtown Washington when the shaking started. She said she didn't realize that it was an earthquake at first, USA TODAY's Fredreka Schouten reports. "I've never been in an earthquake before," she said, standing in her exercise clothes outside her office building at 2:20 p.m. "I thought something was wrong with me, like I had a headache."

Outside, dozens of office workers milled about, comparing notes and trying to reach friends and family members on their mobile phones.

Pack's colleague Caitlin Shea, 22, said she was at her desk when the earthquake struck. "The filing cabinets started shaking. I thought they would topple on us."

She was nervous about re-entering the 12-story building where they work. "I'm afraid of aftershocks," she said.

Update at 2:40 p.m. ET: USA TODAY's Dan Vergano reports that the quake, described as medium-sized, could be felt as far north as Ottawa, Canada. In New York, the Holland Tunnel closed, forcing drivers to back out into Manhattan. In Washington, numerous public buildings were evacuated, including the Pentagon, the Capitol and the Homeland Security Department, as well as all monuments and malls.

Update at 2:36 p.m. ET: The Associated Press quotes the U.S. Weather Service as saying no tsunami is expected after the quake.

Update at 2:30 p.m. ET: The Washington Post quotes a USGS official as saying, "We would certainly expect aftershocks."

Update at 2:29 p.m. ET: The USGS suggests that the quake is the largest to originate in Virginia since May 31, 1897.

Update at 2:26 p.m. ET: The USGS says the quake was centered at a depth of 4.6 miles.

Update at 2:18 p.m. ET: In "the East Coast you have this old hard, cold crust that does a lovely job of transmitting the waves," says Lucy Jones, a seismologist with the U.S. Geological Survey. "This large of an earthquake ... could definitely have been felt hundreds of miles away."

Update at 2:16 p.m. ET: Fox News reports that JFK airport has been shut down because of the quake.

Update at 2:15 p.m. ET: "It scared the heck out of me, I'm still shaking," said Joan Morris, spokeswoman for the northern district of the Virginia Department of Transportation. A few minutes after the quake, there were no reports of damage to roads or bridges in the state, Morris said.

Update at 2:13 p.m. ET: The USGS puts the magnitude of the quake at 5.9.

Update at 2:12 p.m. ET: The quake could be felt in McLean, Va., headquarters of USA TODAY. It caused the building to sway. Some items could be heard falling from shelves. A number of employees left the building.

Update at 2:10 p.m. ET: NBC reports that the quake was centered 9 miles from Mineral, Va., which is 100 miles south of Washington.

Doug Kammerer, meteorologist with the NBC affiliate in Washington, calls the tremor a "very big earthquake for our area."

The quake struck around 1:52 p.m. ET and lasted for about 30 to 45 seconds.

There have been no reports of injuries or widespread damage.

Update at 2 p.m. ET: Reuters reports an earthquake centered near Mineral, Va., rocked the Mid-Atlantic states and was felt as far north at Manhattan and as far south as North Carolina.

Update at 1:57 p.m. ET: The Associated Press reports that the Pentagon is being evacuated.

Fox News reports that several public buildings, including the Capitol, have been evacuated.