Central Canada quakes: A closer look at the region’s risk of tremors
Published Friday, May 17, 2013 11:58AM EDT Last Updated Friday, May 17, 2013 10:55PM EDT
The risk of earthquakes might not spring to mind for residents of Central Canada, but it’s actually one of several regions of the country prone to earth shaking.
According to Natural Resources Canada, approximately 450 earthquakes occur in eastern Canada annually, but only a small fraction exceed a magnitude of 4 on the Richter scale.
On average, three earthquakes with a magnitude of 5 or greater will occur in the area in a given decade. Magnitude 5 is considered the threshold for any significant damage.
People in eastern Ontario and southwestern Quebec felt the ground shake Friday morning, after a 4.8 magnitude quake hit near Ottawa shortly after 9:45 a.m.
The earthquake struck in the Western Quebec Seismic Zone, which encompasses the Ottawa Valley from Montreal to Temiscaming, and the Laurentians and Eastern Ontario. Montreal, Ottawa and Cornwall are located within the zone.
Natural Resources Canada’s 30-day earthquake tracker shows over 40 earthquake “events” in various parts of eastern Canada since April 16. Some recent events include a 2.7-magnitude earthquake that occurred near Constance Bay, Ont. on Wednesday, and a 1.5 magnitude earthquake near Charlevoix, Que., on Thursday.
On May 6, a 3.5 magnitude earthquake was felt 35 kilometres north of Cap-Chat, Que. This was reported as “felt.”
In June 2010, a 5.0-magnitude earthquake hit Ontario, Quebec and parts of northeastern United States, forcing a Quebec town near the quake’s epicentre to declare a state of emergency after the tremor damaged several buildings.
According to Natural Resources Canada, one of the largest earthquakes ever in Canada registered a magnitude of 7 when it hit the Charlevoix-Kamouraska Region of Quebec in February, 1663. The tremor caused large-scale landslides near the St. Maurice and Saguenay rivers.
While Eastern Canada has its share of seismic activity, the offshore region west of Vancouver Island is considered the most earthquake-prone region in Canada. The area has registered over 100 earthquakes of magnitude 5 or greater in the past 70 years.
Regions with the least seismic activity include Saskatchewan, Manitoba and Northern Ontario.
Source: Natural Resources Canada