A kinematic model of the Hsiaolin landslide calibrated to the morphology of the landslide deposit

This paper presents results of a case study on the Hsiaolin catastrophic landslide, including its kinematic process and the geometry of deposition. Based on geomorphologic analysis, the landslide initiated in thick, multi-aged colluvium soils at the headwaters of a small stream upslope of Hsiaolin village. A 3D discrete element program, PFC3D was used to model the kinematic process that led to the landslide and destruction of Hsiaolin village. The landslide advanced from debris slide to debris avalanche during the kinematic process. Assuming a friction coefficient of each particle of 0.1, the predicted maximum velocity was about 70 m/s, a velocity which permits the debris to cross Qishanxi stream and deposit on the opposite bank. Based on simulation results, Hsiaolin village was inundated in 60 to 65 s after failure initiation and at 112 s after the event, the debris avalanche came to rest, forming a landslide dam.