1. School of Earth Sciences, Chengdu University of Technology, Chengdu 610059, China
2. State Key Laboratory of Geological Hazard Prevention and Geological Environment Protection, Chengdu University of Technology, Chengdu 610059, China
3. Technology Service Center of Surveying and Mapping, Sichuan Bureau of Surveying, Mapping and Geoinformation, Chengdu 610081, China
4. School of Resources and Environment, University of Electronic Science and Technology of China, Chengdu 610054, China
5. Huffington Department of Earth Sciences, Southern Methodist University, Dallas, TX 75275, USA