SPH-based numerical modeling for the post-failure behavior of the landslides triggered by the 2016 Kumamoto earthquake

Abstract

Background: The 2016 Kumamoto earthquake triggered many fast landslides in Kyushu Region, Japan, which caused great damages and increased difficulty of rescue after the earthquake. The post-failure behavior analysis of the earthquake-triggered landslides is of great importance to determine the hazardous areas and estimate the extent of damage. Results: The features of the landslides triggered by the Kumamoto earthquake were presented and the damages caused were described based on the field investigation. Then, a mesh-free particle method called smoothed particle hydrodynamics (SPH) was introduced and a 3D numerical model was established based on a Bingham flow model and the equations of continuity and motion. Applying this model, two typical fast landslides in the Kumamoto earthquake zone were simulated. Their propagations were reproduced and the time histories of the velocity and run-out distance were obtained. Conclusions: The run-out distances simulated matched the in-situ evidences, thus verifying the calculation accuracy of the SPH model. The SPH-based approach presented in this work for the post-failure behavior analysis should contribute to the prevention and mitigation of fast landslide disaster.