#cryoseism

A frost quake, otherwise known as a cryoseism might be the reason. 

It might be cold enough in Chicago right now to make the ground shake.

Local news station WGN reported today (Jan 30th) that its viewers had heard "frost quakes" in the city overnight, after WGN itself had posted about frost quakes -- so who knows if the claims are even real?

Frost quakes, or cryoseisms, occur when water trapped underground freezes suddenly as the temperature drops, causing it to expand. (Water expands as it freezes.) All that rapidly expanding water underground can split rocks and put stress on the soil, causing loud booms.  

FROSTQUAKES

If the just plain **** cold isn’t bad enough, don’t be surprised if you find yourself rolled out of your bed some frigid night in what felt like an earthquake.

Frostquakes may feel like a typical tectonic earthquake – there may be shaking, there may be rattling, books might fall from shelves, there might be things that go boom in the night; most frostquakes occur between midnight and dawn. Frostquakes can reach what feels like a magnitude 4 on the Richter scale, though they are so localized that they fail to show up on seismographs. A bit more technical sounding term for this phenomenon is “Cryoseism” (from the Greek, Kryo for cold, and “seismos” for earthquake).

Frostquakes are caused by the freezing of subsurface water. Water turning to ice is a powerful agent of a geologic process (ice fracturing) that can force (http://tinyurl.com/nsctgau) rocks to crack, mountains to split, and exfoliation of solid stone surfaces. When water that is present in shallow soils and sediments or in cracks and fissures in the ground freezes, it gains ~9% in volume when it becomes ice. This expansion can occur abruptly in extremely frigid temperature conditions, even explosively, and cause fracturing in the shallow subsurface. This sets off shockwaves that act the same as seismic shockwaves.

Cryoseisms are also phenomena that accompany glaciation, but since this cold snap is not expected to last long enough to blanket Ohio with rivers of ice, be thankful that we haven’t got THAT ****ing cold enough yet!

Annie R

Photo: by Anna Batsi with a bit of editing by me.

FROST QUAKES. It's like how ice can expand and ruin roadways and break rock formations, but...in one very swift BOOM.

Cryoseism: Did you wake up with a bang this morning?

You may not have been dreaming when you thought you heard a loud sound in the early morning. The phenomenon is called cryoseism and was also reported on Christmas eve around the GTA.

Why is this happening and what is cryoseism?  Cryoseism occurs when the ground and rock contains a significant amount of water, and as the temperatures rapidly dip, the water freezes expanding by 9%, putting stress on the surrounding rock. The stress releases explosively creating a boom as the ground cracks. The Great Lakes area seems to record many of these events, and the frequency of the ones here in Toronto have been attributed to the ice storm and the very cold temperatures we have been experiencing this winter.

More information

CBC: The science of frost quakes

ROMKids: Ice Storm Hits Toronto: Broken trees line the streets, 250,000+ lose power, & Instagram accounts fill with photos of ice

Original post found HERE.

Image Credits

Frost feathers: By Julochka, February 2011 via Creative Commons Attribution.

Frost: By Oliver H, February 2013 via Creative Commons Attribution.

Do your referencing right now, no excuses