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2D inversion of 3D magnetotelluric data: The Kayabe dataset

Abstract

In the last two Magnetotelluric Data Interpretation Workshops (MT-DIW) the participants were asked to model the Kayabe magnetotelluric dataset, a dense (100 m) grid of thirteen lines, with thirteen stations in each line. Bahr’s phase-sensitive skew and the Groom and Bailey decomposition were used to select those lines for which the data could be considered two-dimensional. For these lines we used a 2D inversion algorithm to obtain a series of resistivity models for the earth. Finally, we constructed a 3D model using the 2D models and critically examined the validity and practicality of this approach based on 3D model study. We found that in the Kayabe dataset case the common practice of using 2D models to depict 3D models, can only be used to create a starting model for 3D interpretation. The sequential 2D models as a representation of a 3D body is unacceptable in terms of fit to the observed data. We question the validity of some of the conductivity structures in the 2D models, as they can be mere artifacts created by the algorithm to match 3D effects.

References

  1. Bahr, K., Interpretation of the magnetotelluric impedance tensor: regional induction and local telluric distortion, J. Geophys., 62, 119–127, 1988.

    Google Scholar 

  2. Chave, A. and A. G. Jones, Electric and magnetic field galvanic distortion decomposition of BC87 data, J. Geomag. Geoelectr., 49, 767–789, 1997.

    Article  Google Scholar 

  3. Groom, R. W. and R. C. Bailey, Decomposition of magnetotelluric impedance tensors in the presence of local three-dimensional galvanic distortions, J. Geophys. Res., 94, 1913–1925, 1989.

    Article  Google Scholar 

  4. Jones, A. G., Static shift of magnetotelluric and its removal in a sedimentary environment, Geophysics, 43, 1157–1166, 1988.

    Google Scholar 

  5. Ledo, J. J., P. Queralt, and J. Pous, Effects of galvanic distortion on magne-totelluric data over a three-dimensional structures, Geophys. J. Int., 132, 295–301, 1998.

    Article  Google Scholar 

  6. Mackie, R. L., J. T. Smith, and T. R. Madden, Three-dimensional electro-magnetic modeling using finite difference equations: the magnetotelluric example, Radio Sci., 29(4), 923–935, 1994.

    Article  Google Scholar 

  7. McNeice, G. and A. G. Jones, Multisite, multifrequency tensor decomposition of magnetotelluric data, in Society of Exploration Geophysicists 66th Annual Meeting, Expanded Abstracts, pp. 281–284, 1996.

  8. Takasugi, S., Analyses of magnetotelluric fields for a three dimensional Earth on the basis of the transfer functions, J. Geomag. Geoelectr., 44, 325–344, 1992.

    Article  Google Scholar 

  9. Takasugi, S., K. Tanaka, N. Kawakami, and S. Muramatsu, High spatial resolution of the resistivity structure revealed by a dense network MT measurements—A case study in the Minabikayabe area, Hokkaido, Japan, J. Geomag. Geoelectr., 44, 289–308, 1992.

    Article  Google Scholar 

  10. Torres-Verdin, C. and F. X. Bostick, Implication of the Born approximation for the magnetotelluric problem in three-dimensional environments, Geophysics, 57, 587–602, 1992.

    Article  Google Scholar 

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Correspondence to Xavier Garcia.

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Garcia, X., Ledo, J. & Queralt, P. 2D inversion of 3D magnetotelluric data: The Kayabe dataset. Earth Planet Sp 51, 1135–1143 (1999). https://doi.org/10.1186/BF03351587

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Keywords

  • Apparent Resistivity
  • Impedance Tensor
  • Magnetotelluric Data
  • Strike Angle
  • Geoelectrical Structure