Rare? Surely the Eastern provinces of Canada are as susceptible to the effects of plate tectonics as any other area, even though they’re not as close to a subduction zone (where the undersea ocean plate is subducting under the North American plate) as we are on the West Coast and have longer periods of quiescence. Historically there have been some big quakes on the East Coast in places like New York City and Charleston, SC.
Here’s a chart of historical seismicity in the Eastern provinces between 1900 and 2001. It is colorful enough to be a chart of the fall foliage.