"At first I thought maybe the Metro was running under our office but as the tremors got stronger I realized what was going on," said Editor-in-Chief Sarah Snell Cooke.

A few blocks away, "I did think at first it was an explosion and then ran outside and saw the lamp posts swaying and realized right away it was an earthquake," said Sarah Turner, director of public affairs for the Maryland/DC Credit Union Association. 

Turner, in the trade group's Capitol Hill offices, said the quake lasted about 10-15 seconds and "since I felt them before you knew that shaking was an earthquake."

She said the trade group's offices in Columbia, Md., also felt the tremors.

The Credit Union Association of New York said its Albany offices experienced the shaking, too, but there were no evacuations.

At Belvoir FCU in Woodbridge, Va., about 65 miles from the epicenter, chief marketing officer Jason Lindstrom said he at first thought construction in a parking lot behind his building was responsible for the sudden shaking.

 "There was shaking that at first I thought might have been coming from construction in the parking lot and that something had hit the building, but then pictures fell over on credenzas and dust started coming down from ceiling tiles," he said.

"I guess I brought an earthquake with me," said Lindstrom, who took the position at the suburban D.C. credit union last fall after previously working at SchoolsFirst FCU in Southern California's Orange County.

At the offices of personal finance software specialist Geezeo in Williamsburg, Va., marketing executive Bryan Clagett said he felt "a strong action, two distinctive rolls, with the building moving right then left. The earth felt almost liquid for about 20 seconds."

He said there was no damage to his office or home.

"Hurricane Irene is the one I worry most about," Clagett added.