1887
Volume 37, Issue 3
  • ISSN: 0812-3985
  • E-ISSN: 1834-7533

Abstract

A stable inversion technique has been developed for three-dimensional (3D) interpretation of magnetotelluric (MT) data. The inversion method was based on the Gauss-Newton (linearised least-squares) method with smoothness regularisation. Static shifts were also treated as unknown parameters in the inversion. The forward modelling was done by using the staggered-grid finite difference method. The Akaike Bayesian information criterion (ABIC) was applied to the search for the optimum trade-off parameters while the minimising the data misfit, model roughness, and static shifts. The inversion method was then applied to a large volume MT dataset obtained in the Ogiri geothermal area, southwestern Japan. The inversion was performed stably, resulting in a good fit between the observed and computed apparent resistivities and phases. The 3D resistivity structure recovered was generally similar to that obtained by a two-dimensional (2D) inversion in previous work, although the deeper portion of the 3D model seemed to be more realistic than that of the 2D one. The 3D model was also in a good agreement with the geological interpretation of the geothermal reservoirs. These results indicated the necessity for 3D interpretation in geothermal exploration and in other applications in complicated geological environments.

© 2006 ASEG
Loading

Article metrics loading...

/content/journals/10.1071/EG06223
2006-09-01
2026-01-12

  • From This Site

    /content/journals/10.1071/EG06223
    dcterms_title,dcterms_subject,pub_keyword
    -contentType:Journal -contentType:Contributor -contentType:Concept -contentType:Institution
    10
    5
Loading full text...

Full text loading...

References

  1. Arnason, K., and Flovenz, O.G., 1992, Evaluation of physical methods in geothermal exploration of rifted volcanic crust: Geothermal Resources Council Transactions, 16, 207-214.
  2. Fiordelisi, A., Manzella, A., Buonasorte, G., Larsen, J.C., and Mackie, R.L., 2000, MT methodology in the detection of deep water-dominated geothermal systems: Proceedings, World Geothermal Congress 2000, 1121-1126.
  3. Goko, K., 2000, Structure and hydrology of the Ogiri field, West Kirishima geothermal area, Kyushu, Japan: Geothermics, 29, 127-149.
  4. deGroot-Hedlin, 1991, Removal of static shift in two dimensions by regularized inversion: Geophysics, 56, 2102-2106.
  5. Mackie, R., Rodi, W., and Watts, M.D., 2001, 3-D magnetotelluric inversion for resource exploration: 71st Annual International Meeting, Society of Exploration Geophysicists, Expanded Abstracts, 1501-1504.
  6. Maneja, E.C., Los Banos, C.F., Layugan, D.B., Apuada, N.A., and Rigor, D.M.Jr., 2001, Magnetotelluric sounding in the Northern Negros geothermal filed, Central Philippines: Journal of Geological Society of the Philippines, 56, 184-198.
  7. NEDO, 2000, Study on Geothermal Resources Exploration Techniques, Development of Technology for Reservoir Mass and Heat Flow Characterization, Electrical and Electromagnetic Monitoring, Fiscal Year 1999 Report.
  8. Newman, G., and Alumbaugh, D., 2000, Three-dimensional magnetotelluric inversion using non-linear conjugate gradients: Geophysical Journal International, 140, 410-424.
  9. Ogawa, Y., and Uchida, T, 1996, A two-dimensional magnetotelluric inversion assuming Gaussian static shift: Geophysical Journal International, 126, 69-76.
  10. Romo, J.M., Flores, C, Vega, R., Vazquez, R., Perez-Flores M.A., Gomez-Trevino, E., Esparza, F.J., Quijano, J.E., and Garcia, V.H., 1997, A closely-spaced magnetotelluric study of the Ahuachapan-Chipilapa geothermal field, El Salvador: Geothermics, 26, 627-656.
  11. Sasaki, Y., 1999, 3-D inversion of electrical and electromagnetic data on PC: Proceedings, 2nd International Symposium on Three-Dimensional Electromagnetics, 128-131.
  12. Sasaki, Y, 2001, Three-dimensional inversion of static-shifted magnetotelluric data: Proceedings, 5th SEGJ International Symposium, 185-190.
  13. Uchida, T., 1993, Smooth 2-D inversion for magnetotelluric data based on statistical criterion ABIC: Journal of Geomagnetism and Geoelectricity, 45, 841-858.
  14. Uchida, T, and Mitsuhata, Y., 1995, Two-dimensional inversion and interpretation of magnetotelluric data in the Sumikawa geothermal field, Japan: Geological Survey of Japan, Report No. 282, 17-49.
  15. Uchida, T., Ogawa, Y., Takakura, S., and Mitsuhata, Y., 2000, Geoelectrical investigation the Kakkonda geothermal field, northern Japan: Proceedings, World Geothermal Congress 2000, 1893-1898.
  16. Uchida, T., Lee, T.J., Honda, M, Ashari, and Andan, A, 2002., 2-D and 3-D interpretation of magnetotelluric data in the Bajawa geothermal field, central Flores, Indonesia: Bulletin of Geological Survey of Japan, 53, 265-283.
  17. Zhdanov M.S., Fang, S., and Hursin, G., 2000, Electromagnetic inversion using quasi-linear approximation: Geophysics, 65, 1501-1513.
/content/journals/10.1071/EG06223
Loading
  • Article Type: Research Article
Keyword(s): 3D inversion; geothermal reservoir; magnetotelluric method; Ogiri geothermal area; resistivity

Most Cited This Month Most Cited RSS feed

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error