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Near-surface and topographic distortions in electromagnetic induction

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Abstract

The most revealing description of electromagnetic (EM) distortions due to near-surface inhomogeneities and topography is in terms of galvanic and inductive effects. In either case, the distorted electric and magnetic fields can be best visualized as a vectorial sum of primary and secondary fields. Secondary electric fields due to electric charge build-up in the galvanic case persist to the longest periods. In contrast, the secondary electric and magnetic fields due to inductive, vortex currents disappear at long periods. The static shift of magnetotelluric (MT) apparent resistivity sounding curves is a classic example of the galvanic effect.

Methods to correct for unwanted distortions such as the static shift can be classified into six categories: use of invariant response parameters, curve shifting, statistical averaging, spatial filtering, use of distortion tensors, and computer modeling. Although invariant impedance calculations are simple to make, they cannot, in general, recover the undistorted impedance. Short period curve shifting is best done with auxiliary soundings such as time domain EM; however, this requires multiple surveys. The shifting of long period MT sounding branches is useful if a standard curve is known and can be matched. Statistical averaging of neighboring MT soundings that are conformal but static shifted has proven very effective at removing random distortions if adaquate data are available. The new EMAP (Electromagnetic Array Profiling) method combats the inherent spatial high pass characteristics of EM distortions by low pass operations in data collection and processing. EMAP proposes the continuous, in-field measurement of electric field dipoles to avoid spatial aliasing. Distortion tensor stripping of topographic distortions is possible since terrain is deterministic but stripping the effects of uncertain subsurface inhomogeneities may be misleading. A new decomposition of the MT impedance tensor under the assumption of surficial three-dimensional (3-D) galvanic effects imposed on a one- or two-dimensional (1-D and 2-D) regional setting promises a way to recover the regional structure. There is a continual need for 3-D computer modeling to test new methods and to calculate topographic and regional effects. Computer modeling has established the value of 2-D modeling of the data identified as transverse magnetic (TM) in some 3-D environments. Ideally, EM distortion correction requires continuous, or at least many, data and the application of more than one correction-modeling scheme.

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References

  • Adam, A., Szarka, L., Vero, J., and Wallner, A.: 1986, ‘Magnetotellurics (MT) in Mountains — Noise, Topography and Crustal Inhomogeneity Effects’,Phys. Earth Planet. Inter. 42, 165–177.

    Google Scholar 

  • Andrieux, P. and Wightman, W. E.: 1984, ‘The So-called Static Correction in Magnetotelluric Measurements’, 54th Ann. Internat. Mtg., Soc. Explor. Geophys., Expanded Abstracts, pp. 43–44.

  • Berdichevsky, M. N., Bezruk, I. A., and Chinavera, O. M.: 1973, ‘Magnetotelluric Sounding with the Use of Mathematical Filters (in Russian).Izv. Akad. Nauk SSSR Fiz. Zeml. 3, 72–92.

    Google Scholar 

  • Berdichevsky, M. N. and Dmitriev, V. I.: 1976a, ‘Distortion of Magnetic and Electric Fields by Near-Surface Lateral Inhomogeneities (in Russian)’,Acta Geod., Geophys. Mont. Hung. 11, 447–483.

    Google Scholar 

  • Berdichevsky, M. N. and Dmitriev, V. I.: 1976b, ‘Basic Principles of Interpretation of Magnetotelluric Sounding Curves’, in Adam, A. (ed.),Geoelectric and Geothermal Studies, KAPG Geophysical Monograph, Akademiai Kiado, pp. 165–221.

  • Berdichevsky, M. N., Vanyan, L. L., Kuznetsov, V. A., Levadny, V. T., and Mandelbaum, M.M. Nechaeva, G. P., Okulessky, B. A., Shilosky, P. P., and Shpak, I. P.: 1980, ‘Geoelectrical Model of the Baikal Region’,Phys. Earth Planet. Inter. 22, 1–11.

    Google Scholar 

  • Berdichevsky, M. N. and Zhdanov, M. S.: 1984,Advanced Theory of Deep Geomagnetic Sounding, Elsevier Sci. Pub., Amsterdam, 408 pp.

    Google Scholar 

  • Berdichevsky, M. N., Vanyan, L. L., and Dmitriev, V. I.: 1989, ‘Methods Used in the U.S.S.R. to Reduce Near-Surface Inhomogeneity Effects on Deep Magnetotelluric Sounding’,Phys. Earth Planet. Inter. 53, 194–206.

    Google Scholar 

  • Boersma, J. R. and Jiracek, G. R.: 1987, ‘Three-Dimensional Magnetotelluric Modelling with the Rayleigh-FFT Method’,Internat. Union of Geodesy and Geophysics General Assembly, Vancouver, Canada, Abs. 2, 1452.

    Google Scholar 

  • Bostick, F. X. Jr.: 1977, ‘A Simple Almost Exact Method of MT Analysis’, in Ward, S. (ed.),Workshop on Electrical Methods in Geothermal Exploration, Univ. of Utah Res. Inst., U. S. Geol. Surv. Contract 14-08-0001-g-359, pp. 174–183.

  • Bostick, F. X. Jr.: 1986,Electromagnetic Array Profiling (EMAP): 56th Ann. Internat. Mtg., Soc. Explor. Geophys., Expanded Abstracts, 60–61.

  • Chouteau, M, and Bouchard, K.: 1988, ‘Two-Dimensional Terrain Correction in Magnetotelluric Surveys’,Geophysics 6, 854–862.

    Google Scholar 

  • Dawson, T. W., Weaver, J. T. and Raval, V.: 1982, ‘B-polarization Induction in Two Generalized Thin Sheets at the Surface of a Conducting Half-Space’,Geophys. J. R. Astr. Soc. 69, 209–234.

    Google Scholar 

  • Dmitriev, V. I., Zakharov, E. V., and Kokotushkin, G. A.: 1973,Master Curves for Magnetotelluric Sounding in Homogeneous Media (in Russian).2, Moscow State Univ.

  • Dosso, H. W. and Weaver, J. T.: 1983, ‘The Collective Review Papers Presented at the 6th IAGA Workshop on Electromagnetic Induction in Earth and Moon-Preface’,Geophys. Surv. 6, 103.

    Google Scholar 

  • Eggers, D. E.: 1982, ‘An Eigenstate Formulation of the Magnetotelluric Impedance Tensor’,Geophysics 47, 1204–1214.

    Google Scholar 

  • Fainberg, E. B. and Singer, B. Sh.: 1987, ‘The Influence of Surface Inhomogeneities on Deep Electromagnetic Soundings of the Earth’,Geophys. J. R. Astr. Soc. 90, 61–73.

    Google Scholar 

  • Fischer, G. and Le Quang, B. V. 1981, ‘Topography and Minimization of the Standard Deviations in One-Dimensional Magnetotelluric Modelling’,Geophys. J. R. Astr. Soc. 67, 279–292.

    Google Scholar 

  • Fischer, G. and Weaver, J. T.: 1986, ‘Theoretical Investigation of the Ocean-Coast Effect at a Passive Continental Margin’,Phys. Earth Planet. Inter. 42, 246–254.

    Google Scholar 

  • Fuller, B. D.: 1967, ‘Two-Dimensional Frequency Analysis and Design of Grid Operators: in Mining Geophysics, v. 2, Soc. Expl. Geophys. 658–703.

  • Gamble, T. D., Goubau, W. M., Goldstein, N. W., Miracky, R., Stark, M., and Clarke, J.: 1981, ‘Magnetotelluric Studies at Cerro Prieto’,Geothermics 10, 169–182.

    Google Scholar 

  • Gomez-Trevino, E.: 1987, ‘Should the Electric Line be Straight in Magnetotelluric Surveys?’,Geophys. Prosp. 35, 920–923.

    Google Scholar 

  • Groom, R. W. and Bailey, R. C.: 1989, ‘Decomposition of Magnetotelluric Impedance Tensors in the Presence of Local Three-Dimensional Galvanic Distortion’,J. Geophys. Res. 94, 1913–1925.

    Google Scholar 

  • Gustafson, E. P.: 1986, ‘Three-Dimensional Magnetotelluric Response of the Rio Grande Rift near Socorro, New Mexico’, M.S. Thesis, San Diego State Univ.

  • Harinarayana, T.: 1986,Distortion of Telluric Field Measurements near a Hill, 8th Workshop on Electromagnetic Induction in the Earth and Moon, Neuchâtel, Switzerland, abs., pp. 7–1.

  • Harinarayana, T. and Sarma, S. V. S.: 1982, ‘Topographic Effects on Telluric Field Measurements’,Pure Appl. Geophys. 120, 778–783.

    Google Scholar 

  • Hermance, J. F.: 1982, ‘The Asymptotic Response of Three-Dimensional Basin Offsets to Magnetotelluric Fields at Long Periods: The Effects of Current Channeling’,Geophysics 47, 1562–1573.

    Google Scholar 

  • Hohmann, G. W.: 1988, ‘Numerical Modeling for Electromagnetic Methods of Geophysics’, in Nabighian, M. N. (ed.),Electromagnetic Methods in Applied Geophysics — Theory, v. 1., Soc. Explor. Geophys., Tulsa, pp. 313–363.

    Google Scholar 

  • Honkura, Y.: 1983, ‘Peninsular Effects in Central Japan and Their Relation to the Electrical Conductivity Structure’,J. Geomag. Geoelectr. 35, 39–56.

    Google Scholar 

  • Honkura, Y.: 1987, ‘Elimination of the Regional Coast Effect and a Local Resistivity Structure in the Norboribetsu Geothermal Area, Southwestern Hokkaido’,J. Geomag. Geoelectr. 39, 751–767.

    Google Scholar 

  • Honkura, Y., Isezaki, N., and Yaskawa, K.: 1981, ‘Electrical Conductivity Structure Beneath the Northwestern Philippines Sea as Inferred from the Island Effect on Minami-Diato Island’,J. Geomag. Geoelectr. 33, 365–377.

    Google Scholar 

  • Jensen, V and Seara, J. L.: 1988,Case History: The ECRE Method Applied to a Two-Dimensional Salt Structure, Geometra Ltd., 16 pp.

  • Jiracek, G. R., Gustafson, E., and Mitchell, P. S.: 1983, ‘Magnetotelluric Results Opposing Magma Origin of Crustal Conductors in the Rio Grande Rift’,Tectonophysics 94, 299–326.

    Google Scholar 

  • Jiracek, G. R., Curtis, J. H., Ramirez, J., Martinez, M., and Romo, J.: 1989a, ‘Two-Dimensional Magnetotelluric Inversion of the EMSLAB Lincoln Line’,J. Geophys. Res. 94, 14.145–14.151.

    Google Scholar 

  • Jiracek, G. R., Reddig, R. P., and Kojima, R. K.: 1989b, ‘Application of the Rayleigh-FFT Technique to Magnetotelluric Modelling and Correction’,Phys. Earth Planet. Inter. 53, 365–375.

    Google Scholar 

  • Jones, A. G.: 1983, ‘The Problem of Current Channelling: A Critical Review’,Geophys. Surv. 6, 79–122.

    Google Scholar 

  • Jones, A. G.: 1986, ‘On the Use of Line Current Analogues in Geomagnetic Depth Sounding’,J. Geophys. 60, 56–62.

    Google Scholar 

  • Jones, A. G.: 1988, ‘Static-Shift of Magnetotelluric Data and its Removal in a Sedimentary Basin Environment’,Geophysics 7, 967–978.

    Google Scholar 

  • Jones, F. W. and Pascoe, L. J.: 1973, ‘The Perturbations of Alternating Geomagnetic Fields by Three-Dimensional Structures’,Geophys. J. R. Astr. Soc. 32, 133–154.

    Google Scholar 

  • Jones, F. W. and Price, A. T.: 1970, ‘The Perturbations of Alternating Geomagnetic Fields by Conducting Anomalies’,Geophys. J. R. Astr. Soc. 20, 317–334.

    Google Scholar 

  • Kaikkonen, P., Vanyan, L. L., Martanus, E. R., and Okulessky, B. A.: 1985, ‘Contribution of the Surficial Effects on the Low-frequency Magnetotelluric Anomaly at the Rheingraben Area’,Phys. Earth Planet. Inter. 37, 223–227.

    Google Scholar 

  • Kaufmann, A. A.: 1985, ‘Tutorial: Distribution of Alternating Electrical Charges in a Conducting Medium’,Geophys. Prosp. 33, 171–184.

    Google Scholar 

  • Ku, C. C., Hsieh, M. S., and Lim, S. H.: 1973, ‘The Topographic Effect in Electromagnetic Fields’,Can. J. Earth. Sci. 10, 645–656.

    Google Scholar 

  • Kurtz, R. D., DeLaurier, J. M., and Gupta, J. C.: 1986, ‘A Magnetotelluric Sounding across Vancouver Island Detects the Subducting Juan de Fuca Plate’,Nature 321, 596–599.

    Google Scholar 

  • Lajoie, J. J. and West, G. F.: 1976, ‘The Electromagnetic Response of a Conductive Inhomogeneity in a Layered Earth’,Geophysics 41, 1133–1156.

    Google Scholar 

  • Larsen, J. C.: 1977, ‘Removal of Local Surface Conductivity Effects from low Frequency Mantle Response Curves’,Acta Geodaet. Geophys. et Montanist. Acad. Sci. Hung. 12, 183–186.

    Google Scholar 

  • LaTorraca, G. A., Madden, R. T., and Korringa, J.: 1986, ‘An Analysis of the Magnetotelluric Impedance for Three-Dimensional Conductivity Structures’,Geophysics 51, 1819–1829.

    Google Scholar 

  • Livelybrooks, D. W.: 1986, ‘Modelling Earth Resistivity Structure for MT Data: A Comparison of Rotationally-Invariant and Conventional Earth Response Functions (abs).EOS Trans. Amer. Geophys. Union 67, 918.

    Google Scholar 

  • McNeill, J. D., 1985, ‘The Galvanic Current Component in Electromagnetic Surveys, Geonics Ltd., Tech. Note TN 17, 22 p.

  • Menvielle, M.: 1988, ‘Effects of Crustal Conductivity Heterogeneities on the Electromagnetic Field’,Surveys in Geophysics 9, 319–348.

    Google Scholar 

  • Mikhlin, L. P.: 1984, ‘MT-sounding Curves for a Five-Layer Model with a Surface Elliptical Inclusion (in Russian)’,Fiz. Zemli. 3, 77–80.

    Google Scholar 

  • Morrison, H. F., Dolan, W., and Dey, A.: 1976, ‘Earth Conductivity Determinations Employing a Single Superconducting Coil’,Geophysics 41, 1184–1206.

    Google Scholar 

  • Mozley, E. C.: 1982, ‘An Investigation of the Conductivity Distribution in the Vicinity of a Cascade Volcano’, Ph.D. Thesis, University of California, Berkeley, LBL-15671.

    Google Scholar 

  • Nienaber, W., Dosso, H. W., Law, L. K., Jones, F. W., and Ramaswamy, V.: 1976, ‘An Analogue Model Study of Electromagnetic Induction for Island-Continent Ocean Channels’,Phys. Earth Planet. Inter. 13, 169–183.

    Google Scholar 

  • Park, S. K.: 1985, ‘Distortion of Magnetotelluric Sounding Curves by Three-Dimensional Structures’,Geophysics 50, 785–797.

    Google Scholar 

  • Park, S. K., Orange, A. S., and Madden, T. R.: 1983, ‘Effects of Three-Dimensional Structure on Magnetotelluric Sounding Curves’,Geophysics 48, 1402–1405.

    Google Scholar 

  • Park, S. K. and Torres-Verdin, C.: 1988, ‘A Systematic Approach to the Interpretation of Magnetotelluric Data in Volcanic Environments with Applications to the Quest for Magma in Long Valley, California’,J. Geophys. Res. 93, 13,265–13,283.

    Google Scholar 

  • Parkinson, W. D. and Jones, F. W.: 1979, ‘The Geomagnetic Coast Effect’,Rev. Geophys. Space Phys. 17, 1999–2015.

    Google Scholar 

  • Pellerin, L.: 1988, ‘Use of Transient Electromagnetic Soundings to Correct Static Shifts in Magnetotelluric Data’, M.S. Thesis, Univ. Utah.

  • Poll, H. E., Weaver, J. T., and Jones, A. G.: 1989, ‘Calculations of Voltages for Magnetotelluric Modelling of a Region with Near-Surface Inhomogeneities’,Phys. Earth Planet. Inter. 53, 287–297.

    Google Scholar 

  • Price, A. T.: 1973, ‘The Theory of Geomagnetic Induction’,Phys. Earth Planet. Inter. 7, 227–233.

    Google Scholar 

  • Price, A. T. and Jones, F. W.: 1972, ‘Reply by Authors to Discussion by John F. Hermance’,Geophysics 37, 541–542.

    Google Scholar 

  • Ramaswamy, V., Jones, F. W., and Dosso, H. W.: 1976, ‘A Numerical Study of the Topographic Effect on Electromagnetic Fields in a Three-Dimensional Conductivity Model’,Pure Appl. Geophys. 114, 653–662.

    Google Scholar 

  • Ranganayaki, R. P. and Madden, T. R.: 1980, ‘Generalized Thin Sheet Analysis in Magnetotellurics: An Extension of Price's Analysis’,Geophys. J. R. Astr. Soc. 60, 445–457.

    Google Scholar 

  • Reddig, R. P. and Jiracek, G. R.: 1984,Topographic Modeling and Correction in Magnetotellurics, 54th Ann. Internat. Mtg., Soc. Explor. Geophys., Expanded Abstracts, pp. 44–47.

  • Reddig, R. P., Holcombe, H. T. and Christopherson, K: 1989, ‘Imaging, Inversion and Modeling of Magnetotelluric Data Profiles, in Wannamaker, P. E. (ed.),Soc. Explor. Geophys. publication, Magnetotellurics in Geophysical Exploration (submitted).

  • Reddy, I. K., Rankin, D., and Phillips, R. J.: 1977, ‘Three-Dimensional Modelling in Magnetotelluric and Magnetic Variational Sounding’,Geophys. J. R. Astr. Soc. 51, 313–325.

    Google Scholar 

  • Rokityansky, I. I.: 1982,Geoelectric Investigation of the Earth's Crust and Mantle, Springer-Verlag, Berlin, 381 pp.

    Google Scholar 

  • Schmucker, U.: 1970,Anomalies of Geomagnetic Variations in the Southwestern United States, Bull. Scripps Inst. Oceanogr. Univ. of Calif. Press13, 165 pp.

  • Schmucker, U.: 1971, ‘Interpretation of Induction Anomalies Above Non-Uniform Surface Layers’,Geophysics 36, 156–165.

    Google Scholar 

  • Spies, B. R and Frischknecht, F. C.: 1989, ‘Electromagnetic Sounding’, in Nabighian, M. N. (ed.),Electromagnetic Methods in Applied Geophysics, v.2, Soc. Explor. Geophys. (in press).

  • Sternberg, B. K., Washburne, J. C., and Anderson, R. G.: 1985,Investigation of MT Static Shift Correction Methods, 55th Ann. Internat. Mtg., Soc. Explor. Geophys., Expanded Abstracts, pp. 264–267.

  • Sternberg, B. K., Washburne, J. C., and Pellerin, L.: 1988, ‘Correction for the Static Shift in Magnetotellurics Using Transient Electromagnetic Soundings’,Geophysics 53, 1459–1468.

    Google Scholar 

  • Thayer, R. E.: 1975, ‘Topographic Distortion of Telluric Currents: A Simple Calculation’,Geophysics,40, 91–95.

    Google Scholar 

  • Ting, S. C. and Hohmann, G. W.: 1981, ‘Integral Equation Modeling of Three-Dimensional Magnetotelluric Response’,Geophysics 46, 182–197.

    Google Scholar 

  • Torres-Verdin, C.: 1985, ‘Implications of the Born Approximation for the MT Problem in Three-Dimensional Environments’, M.S. Thesis, Univ. of Texas.

  • Torres-Verdin, C. and Bostick, F. X., Jr.: 1989, ‘Principles of Spatial Surface Electric Field Filtering in Magnetotellurics: Electromagnetic Array Profiling (EMAP)’,Geophysics (submitted).

  • Vanyan, L. L.: 1959, ‘Some Problems of the Theory on the Frequency Soundings of Horizontal Stratifications (in Russian)’,Prikladnaja Geophysika 23, 3–45.

    Google Scholar 

  • Vanyan, L. L.: 1965,Fundamentals of Electromagnetic Sounding (in Russian), Nedra, Moscow, 109 pp.

    Google Scholar 

  • Vanyan, L. L., Debabov, A. S., and Judin, M. N.: 1984,Interpretation of Magnetotelluric Data in Inhomogeneous Media, Nedra, Moscow, 195 pp.

    Google Scholar 

  • Wannamaker, P. E., Hohmann, G. W., and Ward, S. H.: 1984, ‘Magnetotelluric Responses of Three-Dimensional Bodies in Layered Earths’,Geophysics 49, 1517–1533.

    Google Scholar 

  • Wannamaker, P. E., Stodt, J. A., and Rijo, L. 1986, ‘Two-Dimensional Topographic Responses in Magnetotellurics Modeled Using Finite Elements’,Geophysics 51, 2131–2144.

    Google Scholar 

  • Ward, S. H.: 1967, ‘Electromagnetic Theory for Geophysical Application’, inMining Geophysics, v. 2, Soc. Explor. Geophys., pp. 10–196.

  • Weidelt, P.: 1975, ‘Electromagnetic Induction in Three-Dimensional Structures’,J. Geophys,41, 85–109.

    Google Scholar 

  • Wolfgram, P, and Scharberth, J.: 1986,Electrical Conductivity Reference Exploration (ECRE), Geometra Ltd., 18 pp.

  • Word, D. R., Goss, R., and Chambers, D. M.: 1986,An EMAP Case Study. 56th Ann. Internat. Mtg., Soc. Explor. Geophys., Expanded Abstracts, 61–63.

  • Wright, J. L.: 1988,VLF Interpretation Manual, EDA Instruments Inc., 87 pp.

  • Zhang, P., Roberts, R. G., and Pedersen, L. B.: 1986, ‘Magnetotelluric Strike Rules’,Geophysics 52, 267–278.

    Google Scholar 

  • Zhdanov, M. S.: 1987, ‘Application of Space Analysis of Electromagnetic Fields to Investigation of the Geoelectrical Structure of the Earth’,Phys. App. Geophys. 125, 483–497.

    Google Scholar 

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  1. Department of Geological Sciences, San Diego State University, 92182, San Diego, CA, U.S.A.

    George R. Jiracek

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Jiracek, G.R. Near-surface and topographic distortions in electromagnetic induction. Surv Geophys 11, 163–203 (1990). https://doi.org/10.1007/BF01901659

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