Sunday 28 August 2011

Quebec Earthquake, 27 August 2011

At about 2.25 am on Saturday 27 August 2011, the Canadian province of Quebec suffered a minor earthquake. The quake measured 3.0 on the Richter Scale and occurred at a depth of about 12.8 km, just about large and shallow enough to have been felt, but unlikely to have caused any damage. The epicenter of the quake was about 40 km to the east of Quebec City.

Quebeck sits on the Canadian Shield, an ancient part of the North American Plate, and should in theory be very tectonically stable. Nevertheless it has two distinct earthquake zones, the Charlevoix Seismic Zone in the northeast and the Western Quebec Seismic Zone in the west, though this earthquake occurred in southeast of the state, outside of both zones. The mechanism behind this seismic activity is not well understood, but is being monitored and studied by the Canadian National Seismograph Network. It is thought that this activity is caused by stresses on the North American Plate resulting from the expansion of the Atlantic and the subduction zones along the Pacific Coast.

There has only ever been one death reported due to an earthquake in eastern Canada, that of a young girl in Montreal in 1732, and this report is considered dubious.