Paleoseismology Along Active and Passive Continental Margins

The catastrophic earthquakes in Haiti (2010, M7.0), Chile (2010, M8.8), Japan (2011, M9.0), and Indonesia (2004, M9.3) highlight Earth’s dynamic nature and the profound risks posed by high-magnitude seismic events. These earthquakes often trigger submarine landslides and tsunamis, resulting in significant loss of life and extensive infrastructure damage along both passive and active continental margins. Paleoseismology plays a key role in reconstructing earthquake recurrence beyond historical records, enabling more accurate seismic hazard assessments critical for designing resilient infrastructure and guiding land-use planning.

This presentation integrates geophysical, sedimentological, and geochronological data collected during multiple expeditions to investigate submarine mass movements in regions such as eastern Canada, Patagonia and the Lesser Antilles. Sediment core analyses reveal rapidly deposited layers, including turbidites, as key markers of past seismic activity. Radiometric dating of these deposits has linked several turbidites to historically documented earthquakes. Furthermore, the synchronism of prehistoric turbidites over distances exceeding 250 km strongly suggests their origin from high-magnitude earthquakes. In eastern Canada, a revised epicenter for the 1663 earthquake (M>7) has also been calculated approximately 120 km northeast of the previously proposed location. This adjustment has significant implications for seismic hazard assessment in Québec (Canada), necessitating updates to regional hazard models. Finally, by revealing the recurrence and characteristics of high-magnitude seismic events, such studies are crucial for improving seismic hazard maps and for improving risk mitigation strategies.