Equivalent-Source from 3D Inversion Modeling for Magnetic Data Transformation

Affiliation(s)

Applied Geophysics Research Group, Faculty of Mining and Petroleum Engineering, Bandung Institute of Technology, Bandung, Indonesia.

Applied Geophysics Research Group, Faculty of Mining and Petroleum Engineering, Bandung Institute of Technology, Bandung, Indonesia.

ABSTRACT

The well-known non-uniqueness in modeling of
potential-field data results in an infinite number of
models that fit the data almost equally. This non-uniqueness concept is exploited to devise a method to transform
the magnetic data based on their equivalent-source. The unconstrained 3D magnetic
inversion modeling is used to
obtain the anomalous sources, *i.e.* 3D magnetization distribution in the subsurface. Although the
3D model fitting the data is not geologically feasible, it can serve as
an equivalent-source. The transformations, which are commonly applied to magnetic data
(reduction to the pole, reduction to the equator, upward and downward continuation), are the
response of the equivalent-source with appropriate kernel functions. The application of the method to both synthetic and field data
showed that the transformation of magnetic data using the 3D equivalent-source gave satisfactory results. The method is relatively more stable than the filtering technique, with respect to the noise
present in the data.

KEYWORDS

Potential-Fields; Equivalent-Layer; Non-Uniqueness; Ambiguity; RTP; RTE; Upward Continuation

Potential-Fields; Equivalent-Layer; Non-Uniqueness; Ambiguity; RTP; RTE; Upward Continuation

Cite this paper

H. Grandis, "Equivalent-Source from 3D Inversion Modeling for Magnetic Data Transformation,"*International Journal of Geosciences*, Vol. 4 No. 7, 2013, pp. 1024-1030. doi: 10.4236/ijg.2013.47096.

H. Grandis, "Equivalent-Source from 3D Inversion Modeling for Magnetic Data Transformation,"

References

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[13] M. Fedi and A. Rapolla, “3-D Inversion of Gravity and Magnetic Data with Depth Resolution,” Geophysics, Vol. 64, No. 2, 1999, pp. 452-460. doi:10.1190/1.1444550

[14] A. H. Saad, “Understanding Gravity Gradients—A Tutorial,” Leading Edge, Vol. 25, No. 8, 2006, pp. 942-949. doi:10.1190/1.2335167

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[16] K. L. Mickus and J. H. Hinojosa, “The Complete Gravity Gradient Tensor Derived From The Vertical Component of Gravity: A Fourier Transform Technique,” Journal of Applied Geophysics, Vol. 46, No. 3, 2001, pp. 156-176. doi:10.1016/S0926-9851(01)00031-3

[17] D. W. Oldenburg and Y. Li, “On ‘3-D Inversion of Gravity and Magnetic Data with Depth Resolution’ (M. Fedi and A. Rapolla, Geophysics, 64, 452-460),” Geophysics, Vol. 68, No. 1, 2003, pp. 400-402. doi:10.1190/1.1552007

[1] C. A. Mendonca and J. B. C. Silva, “The Equivalent Data Concept Applied to the Interpolation of Potential Field Data,” Geophysics, Vol. 59, No. 5, 1994, pp. 722-732. doi:10.1190/1.1443630

[2] C. A. Mendonca and J. B. C. Silva, “Interpolation of Potential-Field Data by Equivalent Layer and Minimum Curvature: A Comparative Analysis,” Geophysics, Vol. 60, No. 2, 1995, pp. 399-407. doi:10.1190/1.1443776

[3] G. R. J. Cooper, “Gridding Gravity Data Using an Equivalent Layer,” Computer and Geosciences, Vol. 26, No. 2, 2000, pp. 227-233. doi:10.1016/S0098-3004(99)00089-8

[4] L. Cordell, “A Scattered Equivalent-Source Method for Interpolation and Gridding of Potential-Field Data in Three Dimensions,” Geophysics, Vol. 57, No. 4, 1992, pp. 629-636. doi:10.1190/1.1443275

[5] D. A. Emilia, “Equivalent Sources Used as an Analytic Base for Processing Total Magnetic Field Profiles,” Geophysics, Vol. 38, No. 2, 1973, pp. 339-348. doi:10.1190/1.1440344

[6] J. B. C. Silva, “Reduction to the Pole as an Inverse Problem and Its Application to Low-Latitude Anomalies,” Geophysics, Vol. 51, No. 2, 1986, pp. 369-382. doi:10.1190/1.1442096

[7] W. Menke, “Geophysical Data Analysis: Discrete Inverse Theory,” 3rd Edition, Academic Press, London, 2012.

[8] R. J. Blakely, “Potential Theory in Gravity and Magnetic Applications,” Cambridge University Press, Cambridge, 1995. doi:10.1017/CBO9780511549816

[9] W. H. Press, B. P. Flannery, S. A. Teukolsky and W. T. Vetterling, “Numerical Recipes: The Art of Scientific Computing,” 2nd Edition, Cambridge University Press, Cambridge, 1997.

[10] K. I. Kis, “Transfer Properties of the Reduction of Magnetic Anomalies to the Pole and to the Equator,” Geophysics, Vol. 55, No. 9, 1990, pp. 1141-1147. doi:10.1190/1.1442930

[11] S.-Z. Xu, C.-H. Yang, S. Dai and D. Zhang, “A New Method for Continuation of 3D Potential Fields to a Horizontal Plane,” Geophysics, Vol. 68, No. 6, 2003, pp. 1917-1921. doi:10.1190/1.1635045

[12] Y. Li and D. W. Oldenburg, “3-D Inversion of Magnetic Data,” Geophysics, Vol. 61, No. 2, 1996, pp. 394-408. doi:10.1190/1.1443968

[13] M. Fedi and A. Rapolla, “3-D Inversion of Gravity and Magnetic Data with Depth Resolution,” Geophysics, Vol. 64, No. 2, 1999, pp. 452-460. doi:10.1190/1.1444550

[14] A. H. Saad, “Understanding Gravity Gradients—A Tutorial,” Leading Edge, Vol. 25, No. 8, 2006, pp. 942-949. doi:10.1190/1.2335167

[15] G. Barnes, “Interpolating the Gravity Field Using Full Tensor Gradient Measurements,” First Break, Vol. 97, No. 4, 2012, pp. 97-101.

[16] K. L. Mickus and J. H. Hinojosa, “The Complete Gravity Gradient Tensor Derived From The Vertical Component of Gravity: A Fourier Transform Technique,” Journal of Applied Geophysics, Vol. 46, No. 3, 2001, pp. 156-176. doi:10.1016/S0926-9851(01)00031-3

[17] D. W. Oldenburg and Y. Li, “On ‘3-D Inversion of Gravity and Magnetic Data with Depth Resolution’ (M. Fedi and A. Rapolla, Geophysics, 64, 452-460),” Geophysics, Vol. 68, No. 1, 2003, pp. 400-402. doi:10.1190/1.1552007