Influence factors and stability analysis of plane potential field continuation in space and frequency domains
Fen LIU1,2,3, Wan-Yin WANG1,2,3, Xiao-Lin JI1,2,3
1. College of Geology Engineering and Geomatics,Chang’an University, Xi’an 710054, China; 2. Insititute of Gravity and Magnetic Technology,Chang’an University, Xi’an 710054, China; 3. Key Laboratory of Western China’s Mineral Resources and Geological Engineering, Ministry of Education, Chang’an University, Xi’an 710054, China;
Potential field continuation is one of the important methods of gravity and magnetic potential field data processing, and obtaining high-precision continuation results is particularly important for subsequent data processing and interpretation. Starting with the basic formula of plane potential field continuation, the authors analyzed the factors and the stability that affect the accuracy of continuation results in space and frequency domains. Using the theory model, the authors investigated the buried depth of the top surface of the field source, the length of the section, the method of edge enlargement, the size of the window, the dot pitch and the continuation height, and compared the different influences of these factors in space domain and frequency domain. The theory model test shows that the dot pitch and continuation height have the greatest influence on the continuation results, followed by the section length, the method of edge enlargement and the size of window, with the top surface of the field source exhibiting minimal influence. With the increase of the top surface’s depth, the continuation results accuracy is reduced. Increasing and expanding the length of the section will improve the accuracy of the field continuation results. Selecting the appropriate sliding window can improve the calculation efficiency, with the increasing window radius, the accuracy of the field continuation results is improved, and it can generally be chosen as 20 times of the continuation distance. The accuracy of the field continuation results have similarity in space domain and frequency domain; nevertheless, in space domain, the continuation error is very large when the continuation distance is less than 1 time of the dot pitch, so it needs to encrypt the dot pitch by using the interpolation method in this situation.
刘芬, 王万银, 纪晓琳. 空间域和频率域平面位场延拓影响因素和稳定性分析[J]. 物探与化探, 2019, 43(2): 320-328.
Fen LIU, Wan-Yin WANG, Xiao-Lin JI. Influence factors and stability analysis of plane potential field continuation in space and frequency domains. Geophysical and Geochemical Exploration, 2019, 43(2): 320-328.
Wu Z Y, Den J Z, Wang Y G , et al. Comparative analysis on the iterative methods for downward continuation of gravity field[J]. Computing Techniques for Geophysical and Geochemical Exploration, 2018,40(2):189-196.
Zhang H, Chen L W, Ren Z X , et al. Analysis on convergence of iteration method for potential fields downward continuation and research on robust downward continuation method[J]. Chinese J. Geophys., 2009,52(4):1107-1113.
Xiong G Z . Some problems in the transformation of gravity and magnetic anomalies in mineral prediction -two.The role and problems of upward continuation[J]. Geophysical and Geochemical Exploration, 1992,16(5):358-455.
王建明 . 重磁异常变换中的延拓问题[J].新疆有色金属, 2006(2):11-16.
Wang J M . Continuation in the transformation of gravity and magnetic anomalies[J].Xinjiang Nonferrous Metals, 2006(2):11-16.
曾华霖 . 重力场与重力勘探[M]. 北京: 地质出版社, 2004.
Zemg H L. Gravity field and gravity exploration[M]. Beijing: Geological Publishing Press, 2004.
Wang W Y, Qiu Z Y, Liu J L , et al. There research to the extending edge and interpolation based on the minimum curvature method in potential field data processing[J]. Progress in Geophys., 2009,24(4):1327-1338.
Ma G Q, Meng L S, Du X J , et al. The study of edge expansion and optim ization median filtering method in magnetic data processing[J]. Computing Techniques for Geophysical and Geochemical Exploration, 2010,32(2):194-199.
Duan B C, Xu S Z , et al. A study of the scheme of extending in the processing of separating local field from regional field for magnetic/gravity anomaly[J]. Computing Techniques for Geophysical and Geochemical Exploration, 1997,19(4):298-304