The U.S. Navy officially announced Friday that their supersonic planes were the cause of the shaking felt along the East Coast Thursday.

Two Navy fighter jets from Naval Air Station Patuxent River in Maryland, an F-35C and an F/A-18, were conducting routine flight tests from 9:20 a.m. to around 12:20 p.m. Thursday in the Atlantic Test Ranges off the coast of Maryland and Virginia, said Navy spokeswoman Connie Hempel. “During this time, the flights conducted multiple tests requiring supersonic speeds causing the sonic booms that were felt and heard around noon” off of Maryland, Delaware and, according to residents, Cape May and Atlantic counties.

While the Navy takes precautions to lessen the impact of testing, Hempel said, “in this case, the sonic booms heard and felt yesterday were exacerbated by atmospheric conditions of the day. Yesterday’s temperature inversion and calm surface winds were conducive for sound to propagate further than normal, according to the weather office at the naval air station.”

Steven Lemongello

Senior copy editor for the Press of Atlantic City. Have worked as a reporter, copy editor and news editor with the paper since 1985. A graduate of the University of Delaware.