The City of Ottawa sits right in the middle of earthquake danger. Many earthquakes in Central Canada originate in the Ottawa-Bonnechere Graben which is a trench that lies between the Mattawa and Petawawa faults. The Ottawa river essentially flows through the fissure between theses two faults. Ottawa is also susceptible from seismic activity coming from movements in the North American Continental Plate.
The danger in Ottawa is magnified by the fact that the City sits on layers of Leda Clay which for complex reasons accelerates the impact of Shear (S waves) and causes more damage than if the City sat on bedrock. Ottawa has this in common with Mexico City which has experienced devastating earthquakes in the past. Ottawa sits in the middle of an entire region that is was pushed a pulled by the creation of the Atlantic Ocean. The most significant remaining faults formed the St. Lawrence River.
Unlike the City of Toronto, the City of Ottawa does account for earthquakes in its City Emergency Plan.
Diarmuid D. O'Dea