Cryoseisms, also known as "frost quakes" or "ice quakes," may have been the reason loud booms and banging sounds were reported in the Chicago area, where brutally cold, below-zero wind chills have taken over.
The "frost quake" weather phenomenon occurs when the ground is saturated with water or ice.
Right now, that's the case in the Midwest, where many spots were recently covered with snow that then melted into the ground.