1. China Railway Eryuan Engineering Group Co. Ltd, Chengdu, Sichuan, China
2. Geophysical Survey Center, China Geological Survey, Langfang, Hebei, China
3. School of Geophysics and Information Technology, China University of Geosciences, Beijing, China
4. College of Earth Sciences, Guilin University of Technology, Guilin, Guangxi, China
5. Hebei Institute of Geological Surveying and Mapping, Langfang, Hehei, China
6. School of Geosciences and Info-Physics, Central South University, Changsha, Hunan, China