via.fox40.com
Loud Booms Reported in Chicago Area Could Be ‘Frost Quakes’
CHICAGO — Loud booms or banging sounds reported overnight in Chicago might have been cryoseisms, or frost quakes, caused by the brutal cold gripping the Midwest this week, according to WGN. So, here's how a frost quake happens: First, the ground has to be saturated with water, like it is in the Chicago area right now with all the snow.