Western Quebec Seismic Zone

The Western Quebec Seismic Zone is a seismically active area in the Ottawa Valley in Eastern Ontario and Western Quebec. The zone stretches from Montreal to Témiscaming and from Cornwall up along the Laurentian Mountains.

Significant earthquakes associated with this seismic zone include the 1732 Montreal earthquake, the 1935 Timiskaming earthquake, the 1944 Cornwall–Massena earthquake, and the 2010 Central Canada earthquake.

Between the years 1980 and 2000 there were 16 earthquakes stronger than a Richter 4.0, with many more of a lesser magnitude. The zone averages about one seismic event every five days.

Seismological monitoring of the zone is performed by the Canadian National Seismograph Network.

Because this is the earliest recorded local earthquake, there is little information about it. It is known that it was a powerful earthquake, leaving much devastation but few deaths. It measured 5.8 on the Richter magnitude scale and caused panic, cracks in the ground, and damage to most buildings. The aftershocks could be felt for several days after the initial earthquake.

At the epicenter of the 1935 Timiskaming earthquake, cracks in gravel and sand could be seen. Almost all chimneys were damaged or destroyed, and some cracks developed in brick walls. These conditions persisted 110 km away from the epicenter. The next day, Tee Lake (close to the epicenter) was clouded. It is suspected that sediment which was previously undisturbed was shaken up by the earthquake. This event scored a 7 on the Modified Mercalli Scale.

Although it was only measured as 5.8 on the Richter magnitude scale, the Cornwall earthquake did considerable damage and also scored a 7 on the Modified Mercalli Scale. Roughly 2000 chimneys were damaged or destroyed. One school suffered heavy damage with brick falling through the roof of its gym. Most two-storey buildings were damaged.

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