earthquake washington monument 8 24 2011

A Parks Police helicopter inspects the Washington Monument shortly after an earthquake struck Washington, DC August 23, 2011. One of the strongest earthquakes to strike the U.S. east coast in decades rattled offices Tuesday in downtown Washington and caused panicked evacuations from skyscrapers as far away as New York. The Pentagon, the US Capitol and Union Station in the nation's capital were all evacuated after the 5.9-magnitude quake, which was shallow with its epicenter only 0.6 miles (one kilometer) underground.