After the recent frost quake rumbled throughout the whole of Northern Calgary, seismologists including David Eaton descended on the town, and more specifically the schoolyard where they believed the crack that caused the frost quake initiated.

Saturday morning, these professionals spent about 30 minutes digging around in the snow to find the crack - which they believed could be the source of the strange sound heard by a large number of people last Tuesday.

Sometimes it takes an outside eye for people to find what they're looking for, though - and this situation was no exception. Terri Godin, the mother of a son interested in the seismic event and its cause, discovered the crack about three minutes after arriving and dragging their feet around on the snow. The crack turned out to be about 20 meters long, at least 23 centimeters deep, and a single centimeter wide, and seismologists are still studying it.

This frost quake that those seismologists believe caused the rumbling is quite unlike th earthquakes that most people are familiar with. When ice is at such a high density in these winter months, it can often be pulled apart due to sudden changes in the ice's structure. When these changes happen, the ice breaks violently and causes a crack such as the one in Calgary, along with causing a minor seismic event.

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Online:
http://www.calgaryherald.com/news/Calgary+finds+possible+fracture+that+rumbled+north+Calgary/9596357/story.html