2011 Virginia Earthquake Felt By Third Of U.S.

A map shows the wide reach of the 2011 Virginia earthquake. (USGS)

(LiveScience) Nearly a third of the U.S. population reported feeling the earthquake that struck Virginia last year, probably more than any other earthquake in U.S. history, researchers say.

The magnitude 5.8 quake that struck near Mineral, Va., nearly a year ago on Aug. 23, 2011, was felt from Maine to Florida, from Cape Cod to Chicago, and was among the largest ever recorded on the Eastern Seaboard. Damage from the earthquake was relatively light, but effects were nevertheless seen at two landmarks in Washington: the Washington Monument and the National Cathedral.

Although the quake did not wreak significant harm, scientists nevertheless wanted to investigate what effects it had. Such work can shed light on what damage pattern the United States might expect if another earthquake as large or larger happens again in this region.

Key information on the quake came from the U.S. Geological Survey's website, "Did you feel it?" which lets people report when and where they felt a temblor and its intensity. About 148,000 people from more than 3,400 ZIP codes gave responses regarding the Virginia quake, breaking the site record by more than 70,000 responses since it went online in 2000.

Broad reach

All told, scientists determined that the earthquake was felt as far west as the Mississippi River, as far south as northern Florida and as far north as southeastern Canada. The geologic properties of the rock east of the Rocky Mountains cause seismic waves from earthquakes in the eastern United States to propagate more strongly to greater distances from the epicenter than seismic waves in the western part of the country, researchers said.

Since the Virginia earthquake shook several cities, including Baltimore, Philadelphia, New York and Washington, tens of millions of city dwellers probably felt the quake, the scientists estimated. Overall, they say, approximately 100 million people may have felt the quake -- nearly a third of the U.S. population -- meaning it was probably felt by more people than any other temblor in U.S. history.

MORE HERE