Residents in the New York City area felt something shake their homes multiple times Thursday afternoon, leading police to ask residents to stop calling 911 as they awaited word on what caused the rattling.
It turned out that the shaking, felt in New Jersey, New York's Long Island and Connecticut, wasn't caused by an earthquake, as many initially thought, but sonic booms, according to the National Weather Service and other scientists.
The U.S. Navy ended the mystery after a few hours, as the Naval Test Wing Atlantic took possible claim for multiple booms. Test flights out of Naval Air Station Pautuxent River in Maryland that went out over the Atlantic Test Ranges could have caused the tremors, officials said.
U.S. military officials told NBC News that a F-35C Joint Strike Fighter jet likely caused the booms.
NBC10 Philadelphia’s Ted Greenberg was one of the many people in South New Jersey who felt something around 1:30 p.m.
U.S. Geological Survey officials said the booms -- created when an aircraft breaks the sound barrier by traveling more than 768 mph -- were first recorded 8 miles south of Jackson, New Jersey. Eight other spikes were reported at multiple stations in southern New Jersey.
The National Weather Service in Mount Holly reported that the shaking wasn't caused by an earth quake, and confirmed it with scientists at a Columbia University earth science lab that sonic booms were the very likely culprit.
Dr. Mitchell Gold at Columbia's Lamont Doherty Cooperative Seismographic Network told NBC New York that the shaking didn't look seismic in origin, based on the seismographs.
There were fears of an earthquake. Hamilton Township Police reported that they received numerous calls about the shaking and asked people to only call 911 if they had an actual emergency.
A few minutes later, the U.S. Geological Survey centered the shaking near Trenton Road in Hammonton, New Jersey -- not far from tiny Hammonton Municipal Airport -- at 1:24 p.m. and called it a "probable sonic boom" that caused shaking over a series of time.
Shaking was being felt on and off, according to people in various towns. Greenberg reported feeling more rattling around 2, 2:15 and 2:25 p.m.
The rattling initially perplexed state police.
Toms River, New Jersey, police also asked that people not call 911 and said they had received various reports of "earthquake-type-feel" shaking around 2:20 p.m.
"A sonic boom is the thunder-like noise a person on the ground hears when an aircraft or other type of aerospace vehicle flies overhead faster than the speed of sound or supersonic," NASA explains. "Air reacts like a fluid to supersonic objects. As objects travel through the air, the air molecules are pushed aside with great force and this forms a shock wave much like a boat creates a bow wave. The bigger and heavier the aircraft, the more air it displaces."
There weren't initially any reports of planned military training Thursday and Joint Base McGuire-Dix-Lakehurst says they had nothing going on Thursday.
Besides sonic booms and quakes, other things such as big trucks, military exercises and noisy machinery have also been known to cause shaking.