The United States Geological Survey reports a 5.9 magnitude earthquake hit Mineral, Va., about a half hour ago, but the U.S. weather service has issued no tsunami threat. Earthquakes hit the East Coast on occasion, but a quake of this magnitude is unusual. The earthquake was felt up and down the coast, including in Washington D.C. and New York City.

Numerous bystanders and longtime residents evacuated from buildings in New York said they hadn’t felt shaking like this since the terrorist attacks of Sept. 11, 2001. The same thought echoed in the corridors of the Pentagon, too.

With the August recess, D.C. has been relatively empty and quiet, but staffers in the U.S. Capitol and other buildings felt the quake and immediately exited their offices. All federal buildings in D.C. have been or are in the process of being evacuated. D.C. police officers, concerned about potential aftershocks, have warned residents and tourists to avoid the Metro. Some have even expressed concern the Washington monument might be tilting.

The president and reporters at Martha’s Vineyard felt the shaking, too, Ed Henry reported on Fox News. Bret Baier reports he’ll do his show outside this evening, as the police will not allow anyone to reenter the evacuated buildings.

Earthquakes of this size can result in falling chimneys and structural damage to buildings, according to one seismologist. Falling objects and building collapse could also pose the threat of injury — but, so far, no reports of such activity have come down the pike.

The #earthquake Twitterstream immediately lit up with personal anecdotes (“Evacuating building,” “My mom and dad texted within minutes of each other to make sure I’m OK,” etc.) and political quips (“Earthquakes like this never happened when George Bush was president,” “Breaking: Rick Perry blames Obama for the earthquake; Huntsman blames the rest of the GOP field,” etc.). The stream is moving too fast to read. But as no one has been reported hurt, it’s a fun feed to follow.

Update: The National Cathedral has sustained some damage. “At least three pinnacles of the central tower have broken off,” a spokeswoman confirms. Inspections for structural damage underway.

Update: Wall Street traders never left the stock market floor — and the Dow is up. The earthquake clearly no cause for panic.

Update: Congrats to @comradescott, who wins the wittiest tweet contest.

Update (AP): The National Park Service says there’s “absolutely no damage” to the Washington Monument or any other memorial.