A series of sonic booms that shook New Jersey homes and frightened residents Thursday afternoon was caused by military flight tests, military officials said.
U.S. military officials told NBC News that a U.S. military F-35C Joint Strike Fighter jet created a "number of sonic booms" during flight tests off the coast of New Jersey on Thursday. The Joint Strike Fighter was followed by a chase plane as a spotter, officials said.
"Aircraft from Naval Test Wing Atlantic were conducting routine flight testing in the Atlantic Test Ranges this afternoon that included activities which may have resulted in sonic booms," the F-35 program office said in a statement Thursday afternoon.
The jet is based at the Naval Air Station Patuxent River in Maryland.
Earlier Thursday, police departments in South Jersey and parts of New York state were flooded with calls from concerned residents of a possible earthquake in the area.
"We are currently getting numerous calls of tremors/shaking in the area," the Township of Hamilton Police Department said in a post on Twitter earlier Thursday. "The USGS is reporting no earthquake nearby."
NBC Philadelphia's Ted Greenberg said he felt the shaking.
"Windows just rattled again," he said on Twitter, later adding. "And a bigger one just now."
The United States Geological Survey said the shaking was not caused by an earthquake based rather a number of sonic booms.
"At least nine sonic booms were recorded in the following hour and a half," the USGS said on its website.
The sonic booms were reported from southern New Jersey along the Eastern Seaboard to Long Island, New York, the USGS added.
"It almost sounded like an airplane was coming and then the whole house was shaking," Angel Itri, in Atlantic County, New Jersey, told NBC Philadelphia. "We heard something like a boom or like a swishing sound and then the whole house, the windows were shaking."
"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," according to NASA.
The F-35 program office said in their statement that "the Navy takes precautions to lessen the impact of testing and training activities on the community."
"Test aircraft from the naval air station execute supersonic flights almost daily in the test track, and most of these sonic booms are never felt on land," the statement said. "However, under certain atmospheric conditions there is an increased potential to hear the sound."