Geologic Controls on Deep-Seated Landslides

The frequency and scale of landslides in a region are determined by both external forcing and inherent, site-specific susceptibility. During potential triggering events like earthquakes, prolonged periods of elevated pore water pressure, or slope debuttressing, the geotechnical properties of the bedrock ultimately govern whether a hillslope fails as a deep-seated landslide and influence the landslide failure style and kinematics. Although mapped geology is regularly used as a predictor variable for landslide susceptibility models, it is often insufficient in characterizing the nuanced ways in which lithology, stratigraphy, and discontinuities interact to determine how slopes fail in landscapes underlain by heterogenous, fractured bedrock. Using case studies in the Pacific Northwest U.S. and Alaska, I hope to demonstrate that by incorporating more detailed geologic information into regional landslide assessments, we can develop a more complete understanding of the controls on landslide volume, location, and failure style.. 

LaHusen (2025) Geologic Controls on Deep-Seated Landslides, USGS Landslide Hazards Seminar, 16 April 2025.