Vol15 No.4: 793-807
【Title】Seismogenic fault and topography control on the spatial patterns of landslides triggered by the 2017 Jiuzhaigou earthquake
【Author】WU Chun-hao1,2; CUI Peng1,3*; LI Yu-sheng4; Irasema Alcántara AYALA5; HUANG Chao4; YI Shu-jian4
【Addresses】1 Key Laboratory of Mountain Surface Process and Hazards, Institute of Mountain Hazards and Environment, Chinese Academy of Science, Chengdu 610041, China; 2 University of Chinese Academy of Science, Beijing 100049, China; 3 Center for Excellence in Tibetan Plateau Earth Sciences, Chinese Academy of Sciences Beijing 100101, China; 4 State Key Laboratory of Geohazard Prevention and Geoenvironment Protection, Chengdu University of Technology, Chengdu 610059, China; 5 Universidad Nacional Autónoma de México, Instituto de Geografía Circuito Exterior s/n, Ciudad Universitaria, México, D.F., Distrito Federal, MX 04510
【Corresponding author】CUI Peng
【Citation】Wu CH, Cui P, Li YS, et al. (2018) Seismogenic fault and topography control on the spatial patterns of landslides triggered by the 2017 Jiuzhaigou earthquake. Journal of Mountain Science 15(4). https://doi.org/10.1007/s11629-017-4761-9
【Abstract】Jiuzhaigou National Park, located in northwest plateau of Sichuan Province, is a UNESCO World Heritage Site, and one of the most popular scenic areas in China. On August 8, 2017, a Mw 6.5 earthquake occurred 5 km to the west of a major scenic area, causing 25 deaths and injuring 525, and the Park was seriously affected. The objective of this study was to explore the controls of seismogenic fault and topographic factors on the spatial patterns of these landslides. Immediately after the main shock, field survey, remote-sensing investigations, and statistical and spatial analysis were undertaken. At least 2212 earthquake-triggered landslides were identified, covering a total area of 11.8 km2. These were mainly shallow landslides and rock falls. Results demonstrated that landslides exhibited a close spatial correlation with seismogenic faults. More than 85% of the landslides occurred at 2200 to 3700 m elevations. The largest quantity of landslides was recorded in places with local topographic reliefs ranging from 200 to 500 m. Slopes in the range of ~20°-50° are the most susceptible to failure. Landslides occurred mostly on slopes facing east-northeast (ENE), east (E), east-southeast (ESE), and southeast (SE), which were nearly vertical to the orientation of the seismogenic fault slip. The back-slope direction and thin ridge amplification effects were documented. These results provide insights on the control of the spatial pattern of earthquake-triggered landslides modified by the synergetic effect of seismogenic faults and topography.
【Keywords】2017 Jiuzhaigou earthquake; Landslide; Seismogenic fault; Topography; Spatial pattern