Numerical modeling of magnetotelluric phase tensor in the context of 3D/3D formation
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摘要: 当地表存在三维非均匀电导率分布时,区域大地电磁响应发生畸变. 以往对这种畸变研究多假设近地表为三维,区域构造为一维或二维. 对于更一般的三维/三维构造,为了分析并消除这种畸变影响,真实反映地下三维区域构造信息,本文实现了三维大地电磁相位张量积分方程数值算法,并研究在不同地质模型下相位张量响应. 结果表明,相位张量不仅可以反映一般三维构造信息,亦可有效反映复杂近地表构造下三维区域构造信息,而无须假设区域构造为一维或二维,证明相位张量具有较强抗近地表局部非均匀构造干扰能力,能够保持更为一般的三维区域构造信息. 为了加快正演计算,同时保持一定精度,算法采用了积分方程多网格法.Abstract: 3D surface conductivity can cause the distortion of regional magnetotelluric response. Traditional researches for such distortion are based on the assumption that geological structures near earth surface are 3D, and regional structures are 1D or 2D. For more general 3D/3D formation, this paper realized 3D integral equation numerical modeling of magnetotelluric phase tensor and studied the phase tensor responses in the context of different geological models, in order to analyze and remove the distortion, and reflect true 3D subsurface regional formation. The results indicate that, phase tensor not only can reflect common 3D structures, but also can reflect 3D structures covered by complicated 3D surface conductivity distribution without supposing that regional formations are 1D or 2D. For accelerating forward modeling, meanwhile keeping some precision, the forward modeling makes use of integral equation multi-grid method.
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Key words:
- Magnetotelluric /
- 3D/3D formation /
- Distortion /
- Phase tensor /
- Integral equation
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[1] Jiracek G R. Near-surface and topographic distortions in electromagnetic induction. Surv. Geophys., 1990, 11(2-3): 163-203.
[2] Bruton P. Analysis of broadband magnetotelluric data and an application to the Irish Variscides . Galway: National University of Ireland, 1994.
[3] Smith J T. Understanding telluric distortion matrices. Geophys. J. Int., 1995, 122(1): 219-226.
[4] 魏胜, 王家映, 罗志琼. 全MT张量阻抗分解及其应用. // 应用地球物理学进展. 武汉: 中国地质大学出版社, 1998: 38-45. Wei S, Wang J Y, Luo Z Q. Full MT impedance tensor separation and its application. // Applied Geophysics Advance (in Chinese). Wuhan: China University of Geosciences Press, 1998: 38-45.
[5] 王书明. 表面局部三维大地电磁曲线畸变校正: MT畸变校正阻抗张量分解技术. 西北地震学报, 1998, 20(4): 1-11. Wang S M. The correction of magnetotelluric curve distortion caused by surficial local three-dimension inhomogeneities: the impedance tensor decomposition technique for the correction of MT curves distortion. Northwestern Seismological Journal (in Chinese), 1998, 20(4): 1-11.
[6] 晋光文, 孙洁, 王继军. 大地电磁(MT)阻抗张量的正则分解及其初步应用. 地震地质, 1998, 20(3): 243-249. Jin G W, Sun J, Wang J J. Canonical decomposition of the magnetotelluric (MT) impedance tensor and its preliminary application. Seismology and Geology (in Chinese), 1998, 20(3): 243-249.
[7] 赵国泽, 汤吉, 刘铁胜等. 山西阳高—河北容城剖面大地电磁资料的初步解释——阻抗张量分解技术及其应用. 地震地质, 1996, 18(1): 66-74. Zhao G Z, Tang J, Liu T S, et al. Preliminary interpretation of MT data along profile from Yanggao to Rongcheng: application of decomposition of MT impedance tensor. Seismology and Geology (in Chinese), 1996, 18(1): 66-74.
[8] Ritter P. Separation of local and regional information in geomagnetic response functions using hypothetical event analysis . Edinburgh: University of Edinburgh, 1996.
[9] McNeice G W, Jones A G. Multisite, multifrequency tensor decomposition of magnetotelluric data. Geophysics, 2001, 66(1): 158-173.
[10] 晋光文, 孔祥儒. 大地电磁阻抗张量的畸变与分解. 北京: 地震出版社, 2006. Jin G W, Kong X R. MT Impedance Distortion and Separation (in Chinese). Beijing: Seismological Press, 2006.
[11] 李洋, 于鹏, 张罗磊等. 基于混合优化算法的MT阻抗张量畸变分解方法. 地球物理学报, 2010, 53(8): 1924-1930. Li Y, Yu P, Zhang L L, et al. MT distortion decomposition of magnetotelluric impedance tensor based on hybrid optimization algorithm. Chinese J. Geophys. (in Chinese), 2010, 53(8): 1924-1930.
[12] 蔡军涛, 陈小斌, 赵国泽. 大地电磁资料精细处理和二维反演解释技术研究(一)——阻抗张量分解与构造维性分析. 地球物理学报, 2010, 53(10): 2516-2526. Cai J T, Chen X B, Zhao G Z. Refined techniques for data processing and two-dimensional inversion in magnetotelluricⅠ: tensor decomposition and dimensionality analysis. Chinese J. Geophys. (in Chinese), 2010, 53(10): 2516-2526.
[13] 杨长福, 林长佑, 徐世浙. 大地电磁GB张量分解法的改进. 地球物理学报, 2002, 45(增刊): 356-364. Yang C F, Lin C Y, Xu S Z. The improvement of the Groom-Baily's tensor decomposition in magnetotellurics. Chinese J. Geophys. (in Chinese), 2002, 45(Suppl.): 356-364.
[14] 王立凤, 晋光文, 孙洁等. 一种简单的大地电磁阻抗张量畸变分解方法. 西北地震学报, 2001, 23(2): 172-180. Wang L F, Jin G W, Sun J, et al. A simple decomposition method of distortion in magnetotelluric impedance tensor. Northwestern Seismological Journal (in Chinese), 2001, 23(2): 172-180.
[15] Berdichevsky M N, Dmitriev V L, Keller G V. Magnetotellurics in the Context of the Theory of Ill-Posed Problems. Frank: Society of Exploration Geophysicists, 2002.
[16] Berdichevsky M N, Dmitriev V I. Models and Methods of Magnetotellurics. Berlin: Springer-Verlag, 2008.
[17] 陈乐寿, 刘任, 王天生. 大地电磁测深资料处理与解释. 北京: 石油工业出版社, 1989. Chen L S, Liu R, Wang T S. Magnetotelluric Data Processing and Interpretation (in Chinese). Beijing: Oil Industry Press, 1989.
[18] 陈乐寿, 王光锷. 大地电磁测深法. 北京: 地质出版社, 1990. Chen L S, Wang G E. Magnetotelluric Sounding (in Chinese). Beijing: Geological Publishing House, 1990.
[19] Caldwell T G, Bibby H M, Brown C. The magnetotelluric phase tensor. Geophys. J. Int., 2004, 158(2): 457-469.
[20] Weidelt P. Inversion of two-dimensional conductivity structures. Physics of the Earth and Planetary Interiors, 1975, 10(3): 282-291.
[21] Homann G W. Three-dimensional induced polarization and electromagnetic modeling. Geophysics, 1975, 40(2): 301-324.
[22] Born M. Optics. Berlin: Springer, 1933.
[23] Born M, Wolf E. Principles of Optics. 6th ed. New York: Pergamon Press, 1980.
[24] Habasy T M, Groom R W, Spies B R. Beyond the Born and Rytov approximations: a nonlinear approach to electromagnetic scattering. J. Geophys. Res., 1993, 98(B2): 1759-1775.
[25] Zhdanov M S, Fang S. Quasi-linear approximation in 3-D electromagnetic modeling. Geophysics, 1996, 61(3): 646-665.
[26] Zhdanov M S. Geophysical Inverse Theory and Regularization Problems. Amsterdam: Elsevier, 2002.
[27] Fang S, Atlas B, Gao G Z, et al. Fast 3D modeling of borehole induction measurements in dipping and anisotropic formations using a novel approximation technique. Petrophysics, 2004, 45(4): 335-349.
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