Hear a Strange Cracking Noise in This Bitter Cold? It’s Probably a Frostquake

Earthquakes don't strike Michigan often - other than an odd Kalamazoo quake a few years ago, and a bizarre crack that formed in the Upper Peninsula near Menominee - but the sound of the earth cracking can be heard in bitterly cold  winter conditions. It's a rare phenomenon known as a Frostquake.

Scientifically, it's a cryoseism,

a seismic event that may be caused by a sudden cracking action in frozen soil or rock saturated with water or ice. As water drains into the ground, it may eventually freeze and expand under colder temperatures, putting stress on its surroundings. This stress builds up until relieved explosively in the form of a cryoseism.

During the extreme cold event of late January 2019, northern Illinois experienced a rash of ice quakes. So what does it sound like? Q98.5 reports the sound resembles

gunshots coming from {people's] decks outside as wind chill temperatures dropped to minus-30 degrees in some locations.

This video may give you some sense of the frostquake sound.

[h/t WXXQ]