Spatial variation law of vertical derivative zero points for potential field data
Wang Wan-Yin1, Zhang Gong-Cheng2, and Liang Jian-She2
1. Gravity & Magnetic Institute of Chang’an University; College of Geology Engineering and Geomatics, Chang’an University; Key Laboratory of Western China’s Mineral Resources and Geological Engineering, China Ministry of Education, Xi’an, 710054, China.
2. Research Institute of China National Offshore Oil Coporation (CNOOC), Beijing, 100027, China.
Abstract：
In this paper we deduce the analytic solutions of the first- and second-order vertical derivative zero points for gravity anomalies in simple regular models with single, double, and multiple edges and analyze their spatial variation. For another simple regular models where it is difficult to obtain the analytic expression of the zero point, we try to use the profile zero points to analyze the spatial variation. The test results show that the spatial variation laws of both first- and second-order vertical derivative zero points are almost the same but the second-order derivative zero point position is closer to the top surface edge of the geological bodies than the first-order vertical derivative and has a relatively high resolution. Moreover, with an increase in buried depth, for a single boundary model, the vertical derivative zero point location tends to move from the top surface edge to the outside of the buried body but finally converges to a fixed value. For a double boundary model, the vertical derivative zero point location tends to migrate from the top surface edge to the outside of the buried body. For multiple boundary models, the vertical derivative zero point location converges from the top surface edge to the outside of the buried body where some zero points coincide and finally vanish. Finally, the effectiveness and reliability of the proposed method is verified using real field data.
WANG Wan-Yin,ZHANG Gong-Cheng,LIANG Jian-She. Spatial variation law of vertical derivative zero points for potential field data[J]. APPLIED GEOPHYSICS, 2010, 7(3): 197-209.
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