The magnitude 5.8 earthquake that struck Virginia on Tuesday was the largest on the East Coast since one of the same strength in New York in 1944, according to the U.S. Geological Service.
It was the largest in Virginia since a 5.9 temblor in 1897. The largest East Coast quake on record was a 7.3 in South Carolina in 1886.
A 5.8 earthquake releases as much energy as nearly 8 tons of TNT. The devastating March 11 quake in northeastern Japan was a magnitude 9.0. That quake released 63,095 times more energy than the Virginia one.
Nuclear power plants
Federal officials say 12 nuclear plants declared what regulators call "unusual events" after the earthquake Tuesday.
Two nuclear reactors at Virginia's North Anna Power Station, in the same county as the epicenter, were automatically taken off line by safety systems. No damage was reported at the plant, which is being powered by emergency diesel generators.
The quake was also felt at the Surry nuclear plant near Newport News, but a spokesman said both reactors there continued to operate safely. Besides Surry, nuclear plants in Maryland, Michigan, New Jersey, North Carolina and Pennsylvania were placed under increased scrutiny, but continued to operate.
Planes and trains
Thousands of travelers were delayed Tuesday after the earthquake shook airport terminals and forced the evacuation of air traffic control towers at some of the nation's busiest airports.
Immediately after the quake, the FAA ordered planes at airports around the country to stay on the ground rather than fly to airports in New York, Philadelphia, New Jersey, Washington, D.C., and Virginia where traffic was temporarily halted. Among major airports in the region, only New York's LaGuardia continued operations throughout the day. By late afternoon, traffic at all the airports was returning to normal.
Amtrak reported train service along the Northeast Corridor between Baltimore and Washington, D.C., was operating at reduced speeds. Amtrak crews were inspecting stations and railroad infrastructure before returning to normal operation.
Washington's Union Station — which serves Amtrak, commuter trains and the Metro subway — was evacuated due to falling plaster. Metro officials said subway trains were undamaged, but were operating at reduced speeds.
An hour after the earthquake shook the ground around him, President Barack Obama conferred with top aides and was told there had been no early reports of major infrastructure damage.
The president, vacationing on Martha's Vineyard, was teeing off at a golf course when the temblor hit. A statement from the White House did not say whether Obama felt the ground sway. But reporters traveling with him said they had felt it.
Animals knew first
The first warnings of the quake may have occurred at the National Zoo, where officials said some animals seemed to feel it coming before humans did. The red ruffed lemurs began "alarm calling" a full 15 minutes before the quake hit, zoo spokeswoman Pamela Baker-Masson said.
In the Great Ape House, Iris, an orangutan, let out a guttural holler 10 seconds before keepers felt the quake. The flamingos huddled together seconds before people felt the rumbling. The rheas got excited. And the hooded mergansers — a kind of duck — dashed for the safety of the water.