An earthquake with a preliminary magnitude of 5.9 struck Tuesday afternoon near Washington, D.C., the U.S. Geological Survey said.
The epicenter was in Mineral, Virginia. The quake was four miles deep, according to the USGS. Did you feel it? Send CNN an iReport.
To get complete coverage and all the latest updates, click on CNN's main story here. View a CNN Open Story about the quake. CNN Open Story combines iReports with reports from CNNers across the globe on a map and timeline.
Update 3:36 p.m. ET: Terminal A at Washington Reagan National Airport has been evacuated because of an odor of gas, airport spokeswoman Courtney Mickalonis said. Initial sweeps of the building showed no major damage from the earthquake.
Light structural damage has been reported in Culpepper and Orange counties in Virginia, said Laura Southard of the state Emergency Operations Center. She said there have been no reports of injuries in Virginia.
Update 3:28 p.m. ET: The White House and adjacent buildings evacuated as a precaution following the earthquake have been given the all-clear, the U.S. Secret Service said. The FBI and Justice Department have also reopened evacuated buildings.
Update 3:25 p.m. ET: East Coast residents should be prepared to feel aftershocks from Tuesday's earthquake, a U.S. Geological Survey official said.
Update 3:22 p.m. ET: The North Anna nuclear power plant, located 20 miles from the epicenter, is shut down and in a safe condition, a company official and the Louisa County public information office report. There has been no release of nuclear material, Louisa County spokeswoman Amanda Reidelbach said.
Update 3:04 p.m. ET: All national monuments and parks in Washington are "stable but closed" following Tuesday's earthquake, a United States Park Police spokesman Sgt. David Schlosser said. A couple of minor injuries and some minor structural damage have been reported in Washington, following Tuesday's earthquake, according to Schlosser.
Part of the central tower of the National Cathedral, the highest point in Washington, was damaged, according to spokesman Richard Weinberg. "It looks like three of the pinnacles have broken off the central tower," Weinberg told CNN.
Update 3:02 p.m. ET: Amtrak is reporting service disruptions between Washington and Baltimore because of the earthquake, the company reported on Twitter.
Aftershocks are a concern, U.S. Geological Survey seismologist Lucy Jones told CNN. "People should be expecting (them), especially over the next hour or two," she said.
The quake was felt in Philadelphia, Pennsylvania; New York City and on Martha's Vineyard, Massachusetts, where President Barack Obama is vacationing. It's unknown if the president felt the quake.
The Pentagon has been evacuated, CNN's Barbara Starr reports. "When the building began shaking rather violently, hundreds of people began streaming out," she said, because many people thought that the building was under attack. Starr was standing in the Pentagon's press office when the roof started to shake.
Cell phone service has been disrupted in New York City, CNN learned within minutes of the quake.
Updated 2:47 p.m. ET: A "considerable amount" of water from a water pipe has flooded two corridors of the Pentagon, according to an announcement in the building. People who work in those areas are being asked to stay in their offices while workers try to repair the damage.
The National Cathedral in Washington is damaged, CNN has confirmed.
And Dominion Generation, which operates the North Anna nuclear power station in central Virginia a few miles from the epicenter of the earthquake, is trying to reach operational staff at the plant, according to a company spokesman. Landlines to the plant appear to be down.
Shortly after the quake struck, traders in the New York Stock Exchange also felt the quake and shouted to each other, "Keep trading!" CNN's business correspondent Alison Kosik reported from the floor at 2:20 p.m. E.T.
Twitter traffic suggests the quake was felt all over the East Coast.
In Philadelphia, HunterPence3 tweeted, "Wow Earthquake just shook the entire locker room!"
In Cleveland, "tribeinsider" wrote "I'm no expert but i think we just had an earthquake here."
And even in Toronto, Canada, tweets said that the shaking could be felt for minutes.
Pete Krech, who works at a business in Fredericksburg, Virginia, likened the sensation to being on a jolting amusement ride. "I was receiving a supply truck," said Krech, store manager at Mattress Warehouse of Fredericksburg, south of Washington. "I felt a vibration under my feet."
Brendan Wein, a sales representative at Hoffman Nursery in Roxboro, North Carolina, said he thought there was a helicopter flying above his work building.Â "I was literally shaking in my chair," he said.
CNN iReporter Jeff Yapalater said he was in his backyard in New York's Long Island when the earthquake hit. "Suddenly I felt this light swaying of the Earth. I'd never felt that before, so I thought maybe I was experiencing vertigo for a moment, and it lasted maybe 30 seconds ... We're feeling this really far away!" he wrote.
Shook the house and made in creak here in Westernport, MD. My house is 120 years old and first thought was something was giving out on it structurally. I never would have thought it was an earthquake if I hadn't been watching QVC. The lady on there was saying how they were having an earthquake. Then it clicked into place and made sense. SCARY.
I live in a small town in NJ and was suddenly shocked when my whole house started shaking. We evacuated and my dad inspected the house before letting us back in. I never thought something like this would happen!!! I was honestly terrified because at the time i didn't know what it was. When we heard it came from VA we started to seriously worry because my aunt lives in VA. After finally getting in touch with her she informed us she was ok!
I am in Lynchburg, VA and we felt the quake here big time. Our entire building was shaking and it sounded like a freight train coming thru. My husband is 25 miles west of my work and he said our entire house was shaking and he said the same thing about it sounding like a freight train. Freaky!
Here in Raleigh, NC is shook our entire office building.
I didnt feel it here in London....
We're in Jersey City, NJ and felt the floors trembling and then the building swaying and moving...we evacuated right away near a park near the water where there weren't too many tall buildings...
McLean got rocked pretty good! Once as a teaser and then the 2nd time for keeps!
Felt it in Anchorage, Alaska
My wife and I felt the Virginia earthquake way over here in upper Michigan! Very subtle. You had to have been sitting still to have felt it.
Im on vacation and while relaxing outdoors doing some water coloring ,I was thirsty so got a "beer".Laying on my chaise lounge on the rock garden i felt the chaise lounge shake.I thought someone was shaking it, looked up and i was all alone. I had just texted my youngest in VA to warn her of the hurricane ,when she called me and said "did u feel it"? i said yes and began to tear up cuz my Marine son is on the base at Norfolk and my daughter watches his house .Furniture did move but all are ok PHEW!!!!
Felt the earthquake in Columbus Ohio.
Generic compliment about this relatively minor earthquake and how it has inconvenienced my meaningless life.
Facebook group created "I survived the great earthquake of 8-23-11"
I live in Hagerstown Maryland and at the time of the quake I was in Foodlion at the check out.. At first I thought it was just me and then everyone in the store got quiet , I have never in my life felt anything like that.. It was kinda cool but scary at the same time cause I looked up and seen the windows shaking along with the ceiling, the lights were swaying.. My daughter was leaned up against the soda cooler and she couldnt figure out why it was shaking and I looked at the cashier and said earthquake..
Sitting in my chair in middle GA I felt my chair moving and the liquid in my cup was rippling.