Follow CBSPHILLY Facebook  | Twitter

YORK COUNTY, Pa. (CBS) – Sub-zero temperatures may be bringing out a natural phenomenon in Central Pennsylvania. Residents in York County have recently reported hearing loud popping noises.

Some experts say it could be a “Cryo-Seism,” better known as frost quakes.

The phenomenon occurs when water trickles into the ground and freezes.

One expert says while a prolonged period of cold is more likely to cause an event like this, there is no evidence proving it has actually happened.

“Breaking the ground, it is going release seismic energy, we’ll pick that up on our seismograph and we’ll be able to see that energy,” said Taylor Walsh, a professor of geology at Millersville University. “A train track will be shrinking right now so that can break and make a loud noise, tree limbs could be falling.”

He says people may be simply reporting a loud noise that sounds like a frost quake, but isn’t.