For the second time in six years, Philadelphia felt the earth move.
An earthquake shook the region late Thursday afternoon, according to the U.S. Geological Survey.
The agency reported that the center was eight miles from Dover, Del.
Social media lit up with people reporting feeling the shaking for miles around Philadelphia and South Jersey.
The USGS initially reported the earthquake as a 4.4 magnitude. However, at times it was reported as high as 5.1.
In 2011, here's what happened:
It was brief enough to be ignored or misinterpreted - an overzealous demolition crew, perhaps, or a plumbing snafu - and left little evidence in its wake.
But in that 1:51 p.m. quake that lasted for more than 30 seconds Tuesday, the tremor that rumbled beneath the Eastern Seaboard transformed the day.
Businesses closed. Trains and planes screeched to a halt. Rescue workers went on alert. And as much as anything, the historic quake rattled millions of nerves across a dozen states.
Centered near the town of Mineral, Va., the quake rocked communities from Georgia to Canada. With an estimated 5.8 magnitude, it marked the most powerful temblor on the East Coast in 114 years and the third-strongest on record.
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