Numerical earthquake-induced landslide hazard assessment at regional scale in the Colombian Andes

This paper presents an implementation of the SEM-Newmark analysis framework as a method for the earthquake-induced landslide hazard assessment at a regional scale. The implementation relies on a semi-coupling between (i) the physics-based numerical simulation of seismic wave propagation in the 3D domain through the Spectral Element Method (SEM) and (ii) the evaluation of seismic permanent displacements in spatial domains through the direct Newmark Method. The numerical solver was verified against analytical solutions and validated on the case study of the Mesetas earthquake in the Colombian Andes, where hundreds of landslides were triggered. Results highlight the significance of incorporating topographic effects and demonstrate that the proposed framework provides a more accurate hazard assessment compared to traditional pseudo-static approaches. A basic probabilistic hazard zonation approach is introduced, linking landslide occurrence to permanent displacement thresholds, resembling the concept of a fragility curve. The SEM-Newmark analysis framework offers a robust alternative for seismic hazard evaluation in regions with complex topography, improving decision-making for earthquake-prone areas.