Process analysis of the Moxi earthquake-induced Lantianwan landslide in the Dadu River, China

Many large-scale landslides have occurred along the Dadu River, in particular in the middle section of the river, located on the eastern edge of the Qinghai-Tibet Plateau. The large-scale Lantianwan landslide was triggered by the 1786 Moxi earthquake (M-s = 7.75) at Luding, Sichuan province, China. Field investigations and 3D discrete element methods were used to examine the landslide formation mechanism and simulate landslide movement. The evolution of the landslide can be divided into four stages: initiation, high-speed motion, debris flow, and accumulation and river blocking. The results indicate that tension cracking and horizontal sliding were the geological origins of the Lantianwan landslide. The Moxi earthquake combined with the magnifying effect of the topography and the back slope formed deep-dip tensile structural planes in the Lantianwan slope, which triggered the landslide.