There were no major injuries reported nor severe damage, but the 45-second earthquake that hit the East Coast  Tuesday  afternoon gave millions of people  a thorough and efficient  education in what Westerners already know: earthquakes are frightening. 
"It scared the heck out of me. I'm still shaking," said Joan Morris, spokeswoman for the Virginia Department of Transportation.
In  rural Mineral, Va., the quake's epicenter, Marilyn Gutekenst was  clearing lunch dishes from a table on her backyard deck when the trees  began shaking and the deck started to vibrate. "I thought it was a  runaway train" she said. "I thought, 'I don't belong here. I need to  move quickly.'" She ran inside to see picture frames fall off the wall,  plates drop and break, and bookcases topple.
The quake was felt along the Eastern Seaboard  from Georgia  to Canada. The East's tightly-packed earth crust carried  the quake's seismic power farther than an equivalent quake in the West's  spongier terrain, according to Lucy Jones, a seismologist at the U.S. Geological Survey. Shaken and shocked, tourists poured out of the U.S. Capitol  and the Smithsonian museums. At the Empire State Building in New York  City, workers ran down 60 flights of stairs although there had been no  announcement to evacuate.
The earthquake  measured 5.8 in magnitude, but tweeting about the temblor was off the  scale. Social networks lit up with quake reports, commentary and,  quickly, jokes. "D.C. Earthquake Devastation" was the caption on a  heavily re-tweeted photo of a toppled lawn chair.
"I  saw the tweets from DC about earthquake, then 15 seconds later felt it  in NYC. Social media is faster than seismic waves!" wrote Jesse  Friedman, an Internet marketer in Brooklyn.
Though Virginia hadn't had a quake like Tuesday's in 67 years, it was mild by West Coast  standards. California has seen 35 quakes of that size since 1944, when  the last East Coast quake of this magnitude  occurred. So the first  thing everyone had to do was figure out what  was happening.
To  John Gurlach, air-traffic controller at the Morgantown Municipal  Airport in West Virginia, it felt like a B-52 releasing its payload. To  Karen Schaefer, stopped at a traffic light in Raleigh, N.C., it felt  like being on a swaying suspension bridge. "But I knew I wasn't on a  suspension bridge,'' she said. "I was, like, 'Is this an earthquake?'  and I said, 'No, this is Raleigh, N.C.' "
At  W.P. Stewart, an investment management firm on Madison Avenue in New  York, desks started squeaking as the walls behind them moved. "It felt  like someone jumped up and down next to you,'' said Lauren Penza, 32. "I  was looking out the window and I could see what I was looking at  moving.''
As a fire warden for the 21st floor,  she checked to make sure everyone was out before she left. With her was  Kristina Munsch, 31, who had no intention of hanging around for an  announcement. "The room shook,'' she said. "It's not one of those things  you can wait for.''
At first, "I thought it was just me,'' said Al Peace, 39, an employee of the Park Avenue  law firm WilmerHale. When a second wave hit, "I thought the building  was going to collapse.'' About 20 employees left, including Peace's  colleague Brian Rudolph. "They said, 'Did you feel it?' I said, 'No, I'm  busy getting Cheap Trick tickets on the  computer,''' Rudolph said. But he left anyway.
Halley  Pack, a 24-year-old paralegal, was putting on her sneakers in the  basement-level gym of her office building in downtown Washington when  the shaking started.
"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."
"I thought someone  was barreling up the road with a trash truck, but the whole house shook,  and we heard dishes rattling," said Shaun Gallagher of the Forest Brook  Glen development near Newport, Del.
"It felt  and sounded like a big gust of wind came through. I looked outside and  the trees weren't even moving," said Jean Carsten, 59, who was at home  in Bayville, N.J., when she felt the tremors. "My husband said, 'That  was an earthquake.'"
Perhaps inevitably, with the 10th anniversary of the Sept. 11 attacks approaching, some people immediately feared terrorism.
Lloyd Stafford, 71, of Boca Raton,  Fla., was with his grandchildren at the Holocaust Museum in Washington,  D.C., when he heard "a major thump to the building'' that caused gift  shop merchandise to tumble to the floor.
"The  guards looked up, and then they said, in alarm, 'Everybody out,  everybody out!" And then somebody said, "We think it's a bomb.'' That  really motivated everybody to get out of there. They were all kind of  scrambling around,'' he said.
Back in Mineral, Va., Louisa County  spokeswoman Amanda Reidelbach said three of the county's six schools  suffered heavy damage. Several buildings collapsed, but, she said, "We  were lucky." Only minor injuries were reported.