Sunday, February 9, 2014
A cryoseism, also known as an ice quake or a frost quake, may be caused by a sudden cracking action in frozen soil or rock saturated with water or ice. As water drains into 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. wikipedia
This winter has been ripe for frost quakes, known technically as cryoseism. Temperatures have been frigid, but occasional warm-ups have allowed for thawing. And the temperature swings have sometimes been abrupt.
That was the case last weekend in Missouri, where temperatures in the 40s on Saturday gave way to single-digit readings by Sunday night.
In Mark Twain's hometown of Hannibal, Mo., 100 miles north of St. Louis, police and emergency dispatches received several calls within about two hours. Facebook feeds were filled with worries.
Some people compared the noise to a sonic boom that rattles windows, said Michael Hall, executive director of the 911 center that covers the Hannibal area. Others described it as sounding like "somebody banging on their house."
Missouri isn't alone. Frost quakes were reported last month in Canada and in several other states — Indiana, Michigan, Ohio, Wisconsin. abc news