Distribution patterns of the electromagnetic fields of orthogonal horizontal magnetic dipoles as sources in CSRMT
CHEN Xing-Peng1(), WANG Liang1(), LONG Xia1, XI Zhen-Zhu2, QI Qing-Xin1, XUE Jun-Ping1, DAI Yun-Feng3, HU Zi-Jun4
1. Hunan 5D Geosciences Co. Ltd., Changsha 410205, China 2. School of Geosciences and Info-Physics, Central South University, Changsha 410083, China 3. State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Nanjing Hydraulic Research Institute, Nanjing 210029, China 4. School of Information Science and Engineering, Hunan Women's University, Changsha 410004, China
Controlled source radio-magnetotellurics (CSRMT) measurements typically use artificial field sources transmitting at frequencies ranging from 1 to 1 000 kHz. Among the many transmitting sources of the artificial source electromagnetic method, the orthogonal horizontal electric dipole source and the orthogonal horizontal magnetic dipole source are preferred field sources for tensor resistivity measurements. Hence, using the analytical formulas for electromagnetic fields based on the horizontal electric dipole source and the horizontal magnetic dipole source, this study calculated the electromagnetic fields based on the orthogonal horizontal electric dipole source and the orthogonal horizontal magnetic dipole source in the homogeneous half-space model. The results show that: (1) The displacement current needs to be considered at transmitting frequencies above 100 kHz; (2) The effects of displacement current on the tensor apparent resistivity and the impedance phase can be ignored in the far zone; (3) With a constant model resistivity and varying distances between transmitter and receiver, model calculations indicate a larger measurement range in the far zone of the high-frequency electromagnetic field; (4) With a constant distance between transmitter and receiver and varying model resistivities, model calculations suggest that the far-zone range of the electromagnetic field is significantly influenced by resistivity, and that the high-resistivity model requires higher frequencies for achieving far-zone observation conditions.Compared with the electric dipole source, the magnetic dipole source exhibits smaller deviations on the tensor apparent resistivity and impedance phase with the actual value, which is more suitable for geological analysis.
陈兴朋, 王亮, 龙霞, 席振铢, 亓庆新, 薛军平, 戴云峰, 胡子君. CSRMT正交水平发射源电磁场分布规律研究[J]. 物探与化探, 2024, 48(3): 721-735.
CHEN Xing-Peng, WANG Liang, LONG Xia, XI Zhen-Zhu, QI Qing-Xin, XUE Jun-Ping, DAI Yun-Feng, HU Zi-Jun. Distribution patterns of the electromagnetic fields of orthogonal horizontal magnetic dipoles as sources in CSRMT. Geophysical and Geochemical Exploration, 2024, 48(3): 721-735.
Liu Z Y, Chen X B, Wang P J, et al. Field observation experiments and new data processing technologies for controlled source radio-frequency magnetotellurics[C]// Proceedings of the 2021 China Earth Sciences Joint Academic Annual Conference (Ⅶ),2021.
[2]
Bastani M. EnviroMT: A new controlled source/radio magnetotoelluric system[M]. Uppsala: Uppsala Dissertations from the Faculty of Science and Technology, 2001.
[3]
Bastani M, Savvaidis A, Pedersen L B, et al. CSRMT measurements in the frequency range of 1-250 kHz to map a normal fault in the Volvi Basin,Greece[J]. Journal of Applied Geophysics, 2011, 75(2):180-195.
[4]
Muttaqien I. Controlled source radiomagnetotelluric method applications in near surface geophysics[D]. Köln: Universitat zu Köln, 2018.
Tang J T, Ren Z Y, Zhou C, et al. Frequency-domain electromagnetic methods for exploration of the shallow subsurface:A review[J]. Chinese Journal of Geophysics, 2015, 58(8):2681-2705.
Xu Y F. Research on transmitter technology of controlled source radio frequency magnetotelluric (CSRMT) system[D]. Beijing: University of Chinese Academy of Sciences, 2014.
[7]
何继善. 可控源音频大地电磁法[M]. 长沙: 中南工业大学出版社,1990.
[7]
He J S. Controlled source audio-frequency magnetotellurics[M]. Changsha: Central South University of Technology Press,1990.
[8]
汤井田, 何继善. 可控源音频大地电磁法及其应用[M]. 长沙: 中南大学出版社, 2005.
[8]
Tang J T, He J S. Controlled source audio magnetotelluric method and its application[M]. Changsha: Central South University Press, 2005.
[9]
陈乐寿, 王光锷. 大地电磁测深法[M]. 北京: 地质出版社,1990.
[9]
Chen L S, Wang G E. Magnetotelluric sounding method[M]. Beijing: Geological Publishing House,1990.
[10]
周亚东. CSAMT多偶极子源特征与张量测量研究[D]. 成都: 成都理工大学, 2015.
[10]
Zhou Y D. Characteristics of multiple source and study on tensor measurement in CSAMT[D]. Chengdu: Chengdu University of Technology, 2015.
[11]
Saraev A K, Shlykov A A, Bobrov N Y. Tensor CSRMT system with horizontal electrical dipole sources and prospects of its application in Arctic permafrost regions[J]. Eng, 2023, 4(1):569-580.
[12]
Bastani M, Malehmir A, Savvaidis A. Combined use of controlled-source and radio-magnetotelluric methods for near surface studies[C]// 24th International Geophysical Conference and Exhibition, 2015.
[13]
Bastani M, Pedersen L B. Estimation of magnetotelluric transfer functions from radio transmitters[J]. Geophysics, 2001, 66(4):1038-1051.
[14]
Bastani M, Persson L, Mehta S, et al. Boat-towed radio-magnetotellurics—A new technique and case study from the city of Stockholm[J]. Geophysics, 2015, 80(6):B193-B202.
[15]
Tezkan B, Saraev A. A new broadband radiomagnetotelluric instrument:Applications to near surface investigations[J]. Near Surface Geophysics, 2008, 6(4):245-252.
[16]
Simakov A, Saraev A, Antonov N, et al. Mobile and controlled source modifications of the radiomagnetotelluric method and prospects of their applications in the near-surface geophysics[C] // 20th Working Group 1.2 of the International Association of Geomagnetism and Aeronomy (IAGA) Workshop on Electromagnetic Induction in the Earth, 2010.
[17]
Pedersen L B, Bastani M, Dynesius L. Groundwater exploration using combined controlled-source and radiomagnetotelluric techniques[J]. Geophysics, 2005, 70(1):G8-G15.
[18]
Bastani M, Malehmir A, Ismail N, et al. Delineating hydrothermal stockwork copper deposits using controlled-source and radio-magnetotelluric methods:A case study from northeast Iran[J]. Geophysics, 2009, 74(5):B167-B181.
[19]
Ismail N, Schwarz G, Pedersen L B. Investigation of groundwater resources using controlled-source radio magnetotellurics (CSRMT) in glacial deposits in Heby,Sweden[J]. Journal of Applied Geophysics, 2011, 73(1):74-83.
[20]
Shlykov A, Antashchuk K, Saraev A, et al. Applications of the controlled-source radiomagnetotelluric method in near-surface investigations[C]// 9th Congress of the Balkan Geophysical Society, 2017.
[21]
Saraev A, Shlykov A, Tezkan B. Technique and near-surface application of the controlled source radiomagnetotellurics with a horizontal electric dipole[C]// 24th European Meeting of Environmental and Engineering Geophysics, 2018.
[22]
Tezkan B, Georgescu P, Fauzi U. A radiomagnetotelluric survey on an oil-contaminated area near the Brazi Refinery,Romania[J]. Geophysical Prospecting, 2005, 53(3):311-323.
[23]
Tezkan B, Hördt A, Gobashy M. Two-dimensional radiomagnetotelluric investigation of industrial and domestic waste sites in Germany[J]. Journal of Applied Geophysics, 2000, 44(2-3):237-256.
[24]
Bastani M, Wang S G, Malehmir A, et al. Radio-magnetotelluric and controlled-source magnetotelluric surveys on a frozen lake:Opportunities for urban applications in Nordic countries[J]. Near Surface Geophysics, 2022, 20(1):30-45.
[25]
Simakov A E, Saraev A K. Application of the controlled-source RMT method for the solution of engineering tasks in chukotka region[C]// Near Surface 2011—17th EAGE European Meeting of Environmental and Engineering Geophysics, 2011.
[26]
Asghari F S, Smirnova M, Shlykov A, et al. A controlled-source radio-magnetotelluric experiment in Aleksandrovka,Russia[C]// 28th Schmucker-Weidelt-Kolloquium für Elektro-magnetische Tiefenforschung, 2019.
[27]
Asghari F S, Smirnova M, Shlykov A, et al. 2D/3D interpretation of controlled-source radio-magnetotelluric far field data from Aleksandrovka,Russia[C]//29th Schmucker-Weidelt Kolloquium für Elektromagnetische Tiefenforschung,2021.
Xi Z Z, Xu P Y, Long X, et al. The electromagnetic field distribution generated from the orthogonal horizontal magnetic dipole source[J]. Chinese Journal of Geophysics, 2011, 54(6):1642-1648.
[29]
席振铢. 人工源频率倾子测深法[D]. 长沙: 中南大学, 2013.
[29]
Xi Z Z. Artificial source frequency-tripper sounding method[D]. Changsha: Central South University, 2013.
[30]
Shlykov A A, Saraev A K. Wave effects in the field of a high-frequency horizontal electric dipole[J]. Izvestiya,Physics of the Solid Earth, 2014, 50(2):249-262.
[31]
Nabighian M N. Electromagnetic methods in applied geophysics[M]. Houston: Society of Exploration Geophysicists,1988.
[32]
King R W P, Owens M, Wu T T. Lateral electromagnetic waves[M]. New York: Springer New York,1992.
[33]
袁翊. 超低频和极低频电磁波的传播及噪声[M]. 北京: 国防工业出版社, 2011.
[33]
Yuan Y. Propagation and noise of SLF and ELF electromagnetic waves[M]. Beijing: National Defense Industry Press, 2011.
Yao N P, Hou W H, Zhang Q L, et al. Influences of ground conductivity,Earth curvature and ionosphere on long-distance lightning locating[J]. Insulators and Surge Arresters, 2022(2):31-38.
[35]
Key K. Is the fast Hankel transform faster than quadrature?[J]. Geophysics, 2012, 77(3):F21.
