It was the East Coast’s most powerful earthquake in 67 years. Because of the solidity of the earth’s crust on the eastern seaboard - unlike California, where there are networks of active faults - earthquakes tend to be felt over longer distances here, according to Thomas Herring, a geophysics professor at MIT.
Geophysicists said the earthquake was unusually strong for the area, but not unprecedented. In 1897, an earthquake estimated at 5.9 magnitude shook Giles County, Va., according to the US Geological Survey. Eight years ago, a 4.5-magnitude earthquake was recorded in that state.
“Although it’s surprising to see one this large, it’s not completely unheard of to have a large earthquake in a relatively quiet area,’’ said John Bellini, a geophysicist with the National Earthquake Information Center, run by the Geological Survey in Golden, Colo.
Ebel said that many places in the eastern United States that are not typically thought of as earthquake zones have the potential to experience rare, larger quakes. The last major temblor in the Boston area occurred in 1755, when a 6.2-magnitude quake struck off Cape Ann. But smaller quakes occur regularly, and it is far from the first time people in the Bay State have felt the earth shake. For example, in June 2010, a 5.0-magnitude quake on the Ontario-Quebec border was felt in the Greater Boston area.
Even more powerful quakes may have occurred in the Northeast. In a paper published this summer, Ebel argued that a 1663 earthquake in the Charlevoix region of Quebec that caused chimneys to tumble in Roxbury was a 7.5-magnitude quake. In 1925, a 6.2-magnitude quake in the same region was also felt in the Boston area, Ebel said.
“That would have caused somewhat stronger ground shaking’’ in Boston than yesterday, Ebel said. “The reactions of people were very comparable to reactions of people today.’’
