Understanding large rock slides in deglaciated valleys in the Central and Patagonian Andes

The effects of deglaciation on the slope stability of glacial valleys have increasing importance in the context of climate change, with a role on the susceptibility to large-volume rock slides or rock avalanches and catastrophic cascading geohazards. In this talk, we review case studies in the Central and Patagonian Andes of Chile, including two fatal historic events (Parraguirre 1987 and Santa Lucia 2017), and other older and active landslides in which the effects of deglaciation are proposed to be major control in the instability of the rock slopes. This work uses 2D and 3D geotechnical numerical modeling approaches, combined with remote sensing and structural analyses, to improve understanding of how stress state changes linked to deglaciation induce rock damage and progressive failure mechanisms, in combination with lithological or structural controls and climatic triggers. The results provide meaningful information towards a better understanding of the behavior of rock slopes under paraglacial conditions, which are of critical importance for the design of monitoring and detection tools for geohazard assessment strategies in remote, high-mountain areas along the Andean range and other Cordilleran settings.

Sepulveda (2025) Understanding large rock slides in deglaciated valleys in the Central and Patagonian Andes, USGS Landslide Hazards Seminar, 19 March 2025.