A 3.6-magnitude earthquake that startled Marylanders from their slumbers in July might have been the strongest measured tremor on record for the state. With its epicenter near Germantown in Montgomery County, the quake was felt by as many as 3 million people in the Mid-Atlantic region, according to the United States Geological Survey. The 5 a.m. earthquake was felt as far away as south-central New Jersey, as well as in Washington, Northern Virginia, southeastern Pennsylvania and Delaware. People in Columbia, Owings Mills, Carroll County and Odenton reported that the quake was enough to rattle household items and send pets into a tizzy. Odenton resident Paul Muirhead said the temblor woke him up about 5:05 a.m. "I was startled from my sleep as if being shaken," he wrote in an e-mail. "Though there was hardly any light by which to see, I could hear items of mine - large and small - rattling on glass shelves." It was one of the strongest quakes centered in Maryland since European settlement. An earthquake in Annapolis in 1758 has been estimated, from eyewitness accounts, at magnitude 3.5, said Jeffrey Halka, acting director of the Maryland Geological Survey. A 1939 quake centered in Phoenix in Baltimore County has been estimated at magnitude 3.5 to 3.7.
Photo courtesy of the Maryland Geological Survey