Deglacial and postglacial paleoseismological archives in mass movement deposits of lakes of south-central Québec

Investigation of seismic activity in eastern Canada is important for natural hazard management as two major active seismic zones with many historical records are located in the region: the Western Quebec seismic zone (WQSZ) and the Charlevoix–Kamouraska seismic zone (CKSZ), with the latter being the most active in northeastern America. This paper describes and analyses a dataset of high-resolution swath bathymetric imagery, sub-bottom profiles, and sediments cores collected in three lakes (Maskinonge, Aux-Sables, and St-Joseph) located between two active seismic zones. The geomorphology observed on high-resolution swath bathymetric imagery, the acoustic sub-bottom profiles, and the sediment analysis indicate that the lakes were disturbed by three phases of seismically induced mass movements since deglaciation: (i) during the deglacial Champlain Sea transgression and the rapid initial glacio-isostatic rebound between ∼13 and 10.5 ka cal BP; (ii) around 1180 AD; and (iii) the well-documented CKSZ 1663 AD M ...