Vol15 No.2: 380-393
【Title】Characteristics and failure mechanism of an ancient earthquake-induced landslide with an extremely wide distribution area
【Author】HUANG Chao1; LI Yu-sheng1*; YI Shu-jian1; LIU Kai1; WU Chun-hao2,3
【Addresses】1 State Key Laboratory of Geohazard Prevention and Geoenvironment Protection, Chengdu University of Technology, Chengdu 610059, China; 2 Key Laboratory of Mountain Hazards and Surface Process, Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu 610044, China; 3 University of Chinese Academy of Science, Beijing 100049, China
【Citation】Huang C, Li YS, Yi SJ, et al. (2018) Characteristics and failure mechanism of an ancient earthquake-induced landslide with an extremely wide distribution area. Journal of Mountain Science 15(2). https://doi.org/10.1007/s11629-017-4527-4
【Abstract】The Lamuajue landslide is located in Lamuajue village on the right bank of the Meigu River, Sichuan Province, China. This landslide is an ancient landslide with an extremely wide distribution area, covering an area of 19 km2 with a maximum width of 5.5 km and an estimated residual volume of 3×108 m3. The objectives of this study were to identify the characteristics and failure mechanism of this landslide. In this study, based on field investigations, aerial photography, and profile surveys, the boundary, lithology, structure of the strata, and characteristics of the landslide deposits were determined. A gently angled weak interlayer consisting of shale was the main factor contributing to the occurrence of the Lamuajue landslide. The deposition area can be divided into three zones: zone A is an avalanche deposition area mainly composed of blocks, fragments, and debris with diameters ranging from 0.1 m to 3 m; zone B is a residual integrated rock mass deposition area with large blocks, boulders and "fake bedrock"; and zone C is a deposition zone of limestone blocks and fragments. Three types of failure mechanism were analyzed and combined to explain the Lamuajue landslide based on the features of the accumulation area. First, a shattering–sliding mechanism caused by earthquakes in zone A. Second, a sliding mechanism along the weak intercalation caused by gravity and water in zone B. Third, a shattering–ejection mechanism generated by earthquakes in zone C. The results provide a distinctive case for the study of gigantic landslides induced by earthquakes, which is very important for understanding and assessing ancient earthquake-induced landslides.
【Keywords】Earthquake-induced landslide; Lamuajue landslide; Ancient landslide; Geological feature; Failure mechanism