Landslides are one of the most significant geologic hazards that currently threaten human society and infrastructure. As landslide hazards increase as a result of urban expansion, climate variability, and disturbances of land cover, understanding the mechanisms and controls of landslides will be critical for the prediction and assessment of future hazards. Although mechanistic models are somewhat successful in predicting landslide susceptibility, scientific experts still do not know what controls the exact location, size, depth, and, in some cases, the timing of landslides. Moreover, the role of underlying weathered bedrock on subsurface hydrology and landslide occurrence is not well understood. To date, the influence of bedrock fracture patterns and weathering extent on landslide patterns is not adequately quantified. This project aims to improve predictions of landslide occurrence and characteristics by incorporating a fundamental and quantitative understanding of bedrock influences on landslides. Results of the research will be disseminated through teaching, community service, and public outreach. The project will contribute to enhancing academic diversity by encouraging the participation of underrepresented minority students and supporting the early-career development of a female faculty member, a graduate student, and a postdoc. The investigators will integrate research and teaching efforts through the incorporation of landslide studies in undergraduate courses. They will develop an innovative teaching-outreach module for UCLA’s physical sciences division that will strengthen undergraduates’ learning and engage K-12 students through topics in “landslide science.â€
To assess the role of bedrock properties in the occurrences and characteristics of landslides, a robust model of slope stability is required that incorporates the structural and hydromechanical properties of the critical zone, that is the heterogeneous, near surface environment in which complex interactions involving rock, soil, water, air, and living organisms regulate the natural habitat and determine the availability of life-sustaining resources. The investigators plan to incorporate 1) the effects of bedrock fracture patterns and weathering in the critical zone and 2) the transient response of subsurface hydrology on the propensity of shallow and deep-seated landslides. They will synthesize existing datasets of landslides, bedrock, soil, weathering, and fracture patterns, as well as hydrologic properties and signatures within catchments in California and Oregon. These datasets, augmented by their fieldwork, will enable them to develop an integrated approach that resolves the influence of the bedrock weathering and fractures on subsurface hydrology and landslide potential--both the likelihood and extent. This integrated modeling of critical zone structure, subsurface hydrology, and slope failure will allow them to evaluate the effects of 3D topography and subsurface structure on slope stability for shallow and deep-seated landslides.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
