Prediction of rainfall-induced shallow landslide runout integrating hydro-mechanical slope stability analysis

This study introduces a novel, process-based framework for landslide runout assessment of rainfall-induced shallow landslides at the catchment scale, leveraging advanced numerical simulation techniques. A key innovation lies in overcoming a critical limitation of traditional approaches, which typically rely on infinite slope stability models and simplified vertical infiltration assumptions, by integrating slope stability analysis using the Limit Equilibrium (LE) method with transient pore water pressure data from Finite Element (FE) seepage simulations. This integration significantly enhances the accuracy of landslide initiation area prediction. The framework was rigorously validated against two landslide events from the extreme rainfall episode of May 2016, with simulated runout extents closely aligning with observed field data. Subsequently, the framework was applied to multiple potential failure locations across the catchment, producing a simulated landslide runout map that includes predicted runout extents. The simulation results were used to define the relationship between landslide volume, runout area, and angle of reach, providing critical insights for hazard quantification. This research delivers a robust, scalable, and data-efficient tool for regional landslide risk assessment, particularly valuable in data-scarce or resource-constrained settings. Its strong predictive capability and practical adaptability enhance its potential for integration into early warning, land-use planning, and disaster risk management.