User:Gdip181/2005 Thornbury Earthquake

Earthquake rocks Nottawasaga Bay 21 October 2005

A 4.2 magnitude earthquake shook Owen Sound and Grey Bruce and Simcoe Counties yesterday afternoon. The Geological Survey of Canada reports the quake was located at Latitude 44.66 north and Longitude 80.4 west, 12 miles north of Thornbury at 5.16 p.m. The quake was also felt as far away as Lions Head ,Hanover ,Barrie and Stayner.

Seismologist for Natural Resources Canada, Janet Drysdale says its not quite known the cause of the earthquake., but the rocks are reacting to the stresses that are built up within the North Amercian techtonic plate. Drysdale says despite other information regarding the magnitude, she says it was a 4.2 on the richter scale. Drysdale says the 4.5 magnitude is a little too high, and adds the 4.0 was a preliminary number at the point of location. She says the magnitude depends on the initial information that was collected at the time of the earthquake. Eight different monitoring stations reported on the severity of the quake. Drysdale says earthquakes are not very common in Ontario. She says they are usually small, but adds the last earthquake in the Georgian Bay region that was of any significance size, was a 5.2 magnitude quake in 2000. The strongest quake to his this region was a 6.3 shaker that occurred on November 1 1935