Characteristics and numerical runout modeling analysis of the Xinmo landslide in Sichuan, China

A catastrophic landslide hit Mount Fugui, Diexi Township, Mao County, Sichuan Province, at 05:38:58 on June 24, 2017. This landslide buried Xinmo Village, caused 83 deaths, and resulted in enormous losses of life and property. The landslide mass cut out and slid from a high position, loaded continuously, and accumulated at the top of the slope body. Subsequently, the landslide mass was transformed into avalanche debris. This process was a typical chain disaster of avalanche debris triggered by a ridge-top landslide. The total volume, elevation difference, and horizontal distance of the landslide were 1637.6 x 104 m(3), 1200 m, and 2800 m. In this research, the disaster-formation mechanism of the Xinmo Landslide was identified based on a geological field survey and remote sensing satellites. The disaster characteristics of the landslide source zone, debris avalanche zone, and accumulation zone were then numerically simulated. The entire process of the Xinmo Landslide movement was comparatively studied using DAN-W, a dynamic landslide software program, and multiple rheological models. The research findings indicated that the frictional model favorably simulated the movement characteristics of various phases of the Xinmo Landslide. This landslide lasted approximately 120 s, and it had a maximum velocity of movement of 74 m/s. Therefore, the frictional model and its parameters can be used in similar studies to investigate the dynamic disaster effects of ridge-top rock landslides.