By Oren Liebermann

OCEAN CITY, N.J. (CBS) – Nerves were rattled in Atlantic County, South Jersey Saturday morning as a Sonic Boom was heard from miles away, then caused the ground to shake.

Just after 11 a.m., a loud noise rocked Ocean City and other town like Sea Isle City, but it wasn’t an earthquake, like many people initially thought.

READ: Ground Vibration Leaves Some South Jersey Residents Shaken Up

Authorities say it was a Sonic Boom, which could be heard from 30 miles away.

“It was just a really loud sound,” this man said. “I was at home with my son and daughter and it was really loud. It shook my chest.

Another man compared the sound to a construction worker knocking down a wall.

Sonic Booms happen when airplanes, normally fighter jets or high speed bombers exceed the speed of sound. Breaking the sound barrier over land is against FAA regulations, but authorities say this one happened off the coast.

Authorities are still unsure where the jet came from.