Werewolf et al. : Earthquakes are fairly rare in that area in particular and the northeast in general. Having spent may years involved with what you folks call Civil Protection I checked the US Geologic Survey data and this one either ties or exceed the current record VA earthquake which was in 1897 (back when Victoria, God bless her! was queen)
A friend who is a soldier assigned to a congressional building was evacuated as was his fiance who works at the Pentagon.
Here in Massachusetts slight tremors were felt and apparently some slight damage in Boston where, i am told, a cupola on an older office building is leaning over the street now. <serious hat off>
Also, there are reports that White House staff in Martha's Vineyard. who are with the President as he works on his golf game and his tan , have consulted geologists and determined that the source of the earthquake was an obscure fault known as "Bush's Fault"