The Saguenay Graben is a rift valley

Rift valley

A rift valley is a linear-shaped lowland between highlands or mountain ranges created by the action of a geologic rift or fault. This action is manifest as crustal extension, a spreading apart of the surface which is subsequently further deepened by the forces of erosion...

 or graben

Graben

In geology, a graben is a depressed block of land bordered by parallel faults. Graben is German for ditch. Graben is used for both the singular and plural....

 in the geological Grenville Province of southern Quebec

Quebec

Quebec or is a province in east-central Canada. It is the only Canadian province with a predominantly French-speaking population and the only one whose sole official language is French at the provincial level....

, Canada

Canada

Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...

. It is an elongated flat-bottomed basin 250 km (155 mi) long and 50 km (31 mi) wide, bounded by normal faults running parallel to its length.

The faults associated with the Saguenay Graben have been the source for earthquake

Earthquake

An earthquake is the result of a sudden release of energy in the Earth's crust that creates seismic waves. The seismicity, seismism or seismic activity of an area refers to the frequency, type and size of earthquakes experienced over a period of time...

s, including the 1988 Saguenay earthquake

1988 Saguenay earthquake

The 1988 Saguenay earthquake was a 5.9 magnitude earthquake that struck Quebec, Canada on Friday, November 25, 1988. It is one of the largest recorded earthquakes in eastern Canada and eastern North America during the 20th century....

.