Cold Weather Science: Frost Quakes

Photo: Max Pixel
Photo: Max Pixel(WNDU)
Published: Jan. 29, 2019 at 5:45 PM CST
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The State of Wisconsin isn't typically known as an earthquake prone state, but we do see a different kind of quake every now and again, a frost quake.

A frost quake, or a cryoseism, happens when saturated rock or soil cracks following a large temperature drop.

Here's the science behind it. Water sinks into the soil and saturates its surroundings. As temperatures drop well below freezing, the saturated material will freeze and expand. As it expands, it puts stress on its surroundings until the pressure has to be relieved and a small explosion happens. People report hearing loud booms with these quakes, or in some cases, even feeling the earth shake beneath them.

Frost quakes were recorded across the country during the winter of 2013-2014, when we saw bitterly cold temperatures. One was reported in Waupun, WI and caused a 100 foot crack in a driveway.

It takes a few things to make a frost quake possible. Rate of temperature drop is important. In the Waupun case, high temperatures fell from the low 30's, to about zero in the span of three days.

The amount of snow on the ground is also important, since it can act like an insulator for the ground. Frost quakes usually happen when there is little to no snow on the ground.

Even though temperatures this week will rival, or beat what we saw in 2013 and 2013, our snow pack and the cold temperatures we've been seeing for several days make a frost quake less likely.