Geology And Geophysics

Why are people experiencing frost quakes



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Frost quake is rare in the United States. This year the U.S found itself in a winter icy grip. Frost quake occurs when warm air allows water to seep deep into fissures and cracks then down and around the rock and limestone. According to Natural Resources Canada, frost quakes occur near the surface of the earth. The freeze and thaw cycle of snow and rain weakens and break rocks due to high water pressure. 

During the day, a Arctic cold front comes in. The temperature drops quickly. You know what happens when you leave a can of soda in the refrigerator too long. It explodes. This is what happens during a frost quake. The water between the cracks expands so quickly it causes mini explosions of water and ice all over the region. These mini explosions don't actually shake the ground, but are loud enough to startle livestock and unsuspecting people. 

Some might confuse frost quake with ice quake. They are not the same. An ice quake is a non-tectonic seismic event caused by glacier movement. Ice quakes occurs when water pools under a glacier then acts like a lubricant allowing the glacier to move.

A instrument called a seismograph monitors movement of the earth and can sometimes pick up frost quakes if the ground cracks too close to it. This is why frost quakes have in the past been mistaken for earthquakes.

Frost quakes usually happens during the first cold snap of the year when the temperature drops from above freezing to below zero. Frost quakes are very localized they don't show up on seismic equipment and typically occur during midnight and dawn when it's the coldest. 

According to Schmidlin, frost quakes occur on the south side of a house where snow or ice has thawed in the sunlight then freezes at night. You may hear the house creak due to a deep freeze. This happens because wood joints move and the cold makes the wood shrink slightly, thus causing strange noises at night as wood contracts. 

The only time you will hear this "cold boom" is when it's cold. Technically a cold boom is call cryoseismic boom. Cryoseismic is a term that has been reserved for the coldest temperatures. It is considered rare for lower latitudes of the United States continent. These cryoseismic  booms are considered harmless, but will scare sleeping people from their slumber. 

Frost quakes normally strike after a big chill due to a rapid temperature drop called a polar vortex which is a normal part of the polar climate that doesn't go away. In the winter over the North Pole cold air usually form at night circulating from west to east over clear skies that allows heat to escape into space. After a large buildup of cool air over the North Pole the cold air flushes north, south, east, or west. Then a jet stream shifts just enough causing a high pressure front to move over a particular area, recently the United States, and sit in place allowing the cold air to spread over that entire upper midwest.  

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ARTICLE SOURCES AND CITATIONS
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  • InfoBoxCallToAction ActionArrowhttp://www.businessinsider.com/what-is-a-frost-quake-2014-1
  • InfoBoxCallToAction ActionArrowhttp://www.ohio.com/news/cold-temperatures-believed-to-have-caused-frost-quakes-in-northeast-ohio-1.457680
  • InfoBoxCallToAction ActionArrowhttp://www.washingtonpost.com/blogs/capital-weather-gang/wp/2014/01/07/a-cool-weather-phenomenon-that-only-happens-when-its-cold/
  • InfoBoxCallToAction ActionArrowhttp://www.livescience.com/42419-what-is-a-frost-quake.html
  • InfoBoxCallToAction ActionArrowhttp://www.livescience.com/42339-polar-vortex-us-temperatures.html