South New Jersey residents felt the ground shaking Saturday morning, but no earthquakes or military training exercises were reported in the region.
The U.S. Geological Survey suggested a possible sonic boom was the cause.
"I'm in LEH [Little Egg Harbor] and my basement door shook violently for 15 sec or so long enough to creep me out. Sounded like someone was trying to get out," posted a person identified as Dana Re on the Jersey Shore Hurricane News Facebook page.
Another comment, posted by a person identified as John Tefankjian, said he felt his Brigantine house shake, but differently from when fighter jets go by in training.
See the NBCPhiladelphia.com report
"There currently is no training of any type that would have resulted in today's incident," Joint Base McGuire-Dix-Lakehurst spokesman Pascual Flores told NBC News on Saturday.
The New Jersey National Guard last weekend conducted artillery-fire training that it told the public about in advance.
NBCPhiladelphia.com reported that residents in Atlantic, Cape May, Ocean, Salem and Camden County claimed they felt the ground shake.
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Comments on the shaking were also posted on independent Earthquake-Report.com.
"Felt like a rumble, everyone ran outside, we all noticed on our street," said one from Ocean City.
"Whole house started shaking, outside sounded like a bomb with slight shaking," said one from Little Egg Harbor.
NBC News' Jim Gold and NBCPhiladelphia's Lauren DiSanto contributed to this story.
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