What’s shaking in New Jersey? Apparently not an earthquake.

People in the southern part of the state reported feeling the ground vibrate at about 10 a.m. Saturday.

But a geophysicist for the U.S. Geological Survey tells The Press of Atlantic City that although the cause isn’t known, no earthquake was detected.

Paul Caruso says the vibration could have been caused by a thunderstorm off the coast or a sonic boom from a military jet doing flight exercises.

A rare 5.8-magnitude East Coast earthquake centered in Virginia rattled New Jersey in late August, wobbling floors and shaking buildings.

(Source: NBC New York)