1. Research Institute No. 270, CNNC , Nanchang , Jiangxi, 330200 , China
2. School of Geophysics and Geomatics, China University of Geosciences , Wuhan , Hubei, 430074 , China
3. Institute of Geophysics, University of Tehran , Tehran , Iran
4. School of Geophysics and Measurement-Control Technology, East China University of Technology , Nanchang , Jiangxi, 330013 , China