Tectono-geomorphology of the Timiskaming Graben, Western Quebec Seismic Zone

English Abstract:

The Western Quebec Seismic Zone (WQSZ) is one of the most seismically active areas of the ‘stable’ North American craton where intraplate earthquakes pose a risk to older infrastructure built on soft glacial marine clays in the heavily populated cities of Ottawa and Montreal. Evidence suggests that these earthquakes are not a function of a short-lived phase of postglacial rebound but reflect ongoing crustal stresses and intraplate deformation. Within the WQSZ the Timiskaming Graben (TG) is an extension of the Ottawa-Bonnechere Graben and forms a prominent 50 km-wide fault-bounded morphotectonic depression along the Ontario/Quebec border. Lakes Timiskaming and Kipewa lie along the graben and their bottom sediments are extensively deformed by ongoing neotectonic activity in the form of slumps, debris flows and faults. This paper describes the results of on land investigation of the floor of TG surrounding these lakes mapping neotectonic fault scarps, landslides and liquefaction structures (‘sand blows’) using satellite imagery, land-based seismic and ground penetrating radar.