“Frost Quake” Boom Rattles City, Rip in Ground Now Located at Epicentre
The epicenter of what’s now believed to be a ‘frost quake’, has been located in northwest Calgary.
A group of researchers was able to pinpoint the location with help from an amateur seismologist who recorded the quake’s seismic signature on his home-built basement machine.
On Saturday, a group led by Dr David Eaton, descended on Captain Nichola Goddard School in Panorama Hills, scouring the frozen ground for signs of prior movement. It didn’t take long before they found a jagged tear in the earth several meters long, at least 50 cm deep and possibly up to a meter deep.
Frost quakes, also known as cryoseism, occur when prolonged cold temperatures cause water deep in the ground to freeze quickly. That puts pressure on the bedrock, or surrounding frozen soil, causing it to crack. The sudden movement can create loud noise, especially if it takes place close to the surface.
Read more: http://calgary.ctvnews.ca/possible-epicenter-of-frost-quake-found-in-northwest-schoolyard-1.1722711#ixzz2vbN2poaT