1. China University of Geosciences (Beijing), School of Geophysics and Information Technology, Xueyuan Road 29, Haidian District, Beijing 100083, China and National University of Singapore, Department of Civil and Environmental Engineering, Singapore 117576, Singapore. (corresponding author)
2. BGP R&D Center, BGP Sci-Tech Park, Huayang East Road, Zhuozhou 072750, China.