What is a cryoseism?
Dear Jack and Verena,
A cryoseism is the technical name for a frost quake or ice quake caused by the sudden fracturing of soil or rock due to freezing of water in saturated ground. During intense cold, water in the ground freezes at the surface, capping water in the soil beneath it, causing pressure to build as that water freezes. Ice occupies a slighter greater volume than the water from which it comes, causing a gradual widening of cracks in the soil. When a cryoseism occurs, the pressure is released all at once, resulting in a “mini-earthquake.” Such quakes are usually harmless, but can produce a loud pop or boom. Numerous cryoseisms were reported across northern during last winter’s intense late January Polar Vortex when the mercury plunged lower than minus 20.