1. School of Geomatics and Prospecting EngineeringJilin Jianzhu University Changchun 130118 China
2. Department of PhysicsUniversity of Toronto Toronto ON M5S 3G3 Canada
3. College of Geo‐Exploration Science and TechnologyJilin University Changchun 130026 China
4. Sinopec Geophysical Research Institute Nanjing 210014 China