Public schools and a handful of government buildings in Washington remained closed for further assessment, and engineers were taking a closer look at cracks in the Washington Monument and broken capstones at the National Cathedral. Some residents of D.C. suburbs were staying in shelters because of structural concerns at their apartment buildings.

Further south, Tuesday's 5.8-magnitude quake also shattered windows and wrecked grocery stores near its Virginia epicenter. There were no known deaths or serious injuries.

The head of the Federal Emergency Management Agency said the quake serves as a reminder for residents to be prepared.

"We talk about hurricanes this time of year, but we forget that A: earthquakes don't have a season and B: they are not just a western hazard," FEMA administrator Craig Fugate said in an interview Wednesday on ABC's Good Morning America.

When the quake struck, many feared terrorism in New York and Washington — places where nerves are raw as the 10th anniversary of the Sept. 11 terrorist attacks approaches. The tremblor sent many pouring from high-rises like the Empire State Building.