Yan Yan, Southwest Jiaotong University, Chengdu, China, Yifei Cui, State Key Laboratory of Hydroscience and Engineering, Tsinghua University, Beijing, China, Jian Guo, Department of Geological Engineering, Chang'an University, Xi an, China, Dingzhu Liu, Key Laboratory of Mountain Surface Process and Hazards/Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu, China and Sheng Hu, College of Urban and Environmental Sciences, Northwest University, Xi an, China