A 5.9 magnitude earthquake centered northwest of Richmond, Va., shook much of Washington and was felt as far north as Rhode Island and New York City.
The earthquake sent hundreds of people spilling into the street a block from the White House and buildings were also evacuated in North Carolina.
The U.S. Geological Survey said the earthquake was 3.7 miles deep. Shaking was felt at the White House and all over the East Coast, as far south as Chapel Hill, N.C. Parts of the Pentagon, White House and Capitol were evacuated. There were no immediate reports of injuries.
The earthquake was centered near Louisa, Va., which is northwest of Richmond and south of Washington.
President Barack Obama and many of the nation's leaders were out of town on August vacation when the earthquake struck just before two p.m. EDT. The shaking was felt on the Martha's Vineyard golf course as Obama was just starting a round.
The East Coast gets earthquakes, but usually smaller ones and is less prepared than California or Alaska for shaking.
At Reagan National Airport outside Washington, ceiling tiles fell during a few seconds of shaking. Authorities announced it was an earthquake and all flights were put on hold.
At the Pentagon in northern Virginia, a low rumbling built and built to the point that the building was shaking. People ran into the corridors of the government's biggest building and as the shaking continued there were shouts of Evacuate! Evacuate!
In New York, the 26-story federal courthouse in lower Manhattan began swaying and hundreds of people were seen leaving the building. Court officers weren't letting people back in.
The 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.