Visualization of magnetotelluric data with apparent velocity method



Magnetotelluric (MT) field data are usually presented as plots of amplitude and phase MT sounding data vs frequency. Visualization of resistivity changes of geoelectric complexes with the use of apparent resistivity and phase curves give qualitative results only. Quantitative interpretation of MT sounding curves is needed to get geoelectric parameters. For a 1D horizontally layered earth, amplitude curves (apparent resistivity curves) and phase curves can be transformed into apparent velocity curves versus depth of EM field penetration into the conducting earth. Apparent velocity curves can be approximated by straight-line segments corresponding to homogeneous geoelectric layer complexes. Each segment of the apparent velocity curve (with a given angle of inclination) is related with the resistivity and thickness of individual geoelectric complexes. For heterogeneous earth (2D or 3D) vertical component of the magnetic field is directly connected with boundary of geo-electric complexes. It can be used to express components of vectors of apparent velocity. For a 1D horizontally layered earth, a vector of apparent velocity has only the vertical component. For heterogeneous earth horizontal components of apparent velocity also are inducted. The angle of inclination of the total vector of velocity and its value depend on the geometry of studied structure.


magnetotelluric sounding, visualization, apparent velocity, depth of penetration

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Levv S., Oldenburg D. & Wang J., 1988. Subsurface imaging using magnetotelluric data. Geophysics, 53, 104-114.

Lee K.H., Liu G. & Morrison H.F., 1989. A new approach to modeling the electromagnetic response of conductive media. Geophysics, 54, 9, 1180-1192.

Lee K.H. & Xie G., 1993. Subsurface imaging using magnetotelluric data. Geophysics, 56, 6, 780-196.

Miecznik J. & Czerwiński T., 2001. Electromagnetic energy velocity in magnetotelluric sounding interpretation. Abstracts of 63th EAGE Conference and Exhibition, Amsterdam, 1-4, M-24.

Miecznik J., Gajewski A. & Czerwiński T., 2002.Electromagnetic Energy Velocity in Non-homogeneous media. Abstracts of 64th EAGE Conference and Exhibition, Florence, 1-4, D-14.

Molochnov G.W., 1968. Interpretacia magnitotelluriceskich zondirovanij s ispolzovaniem efektivnoj glubiny proniknovenia elektromagnitnogo pola. Fizika Zemli, 9, 88-94.

Stefaniuk M., Wojdyła M., Maksym A., Czerwiński T. & Klityński W., 2004. The structure of the Carpathians basement in the area between Jaslo and Rzeszow as a result of magnetotelluric data interpretation. W: AAPG European region conference with GSA: regional geology and hydrocarbon systems of European & Russian Basins: looking for sweet spots: October 10-13, 2004 Prague, official program & abstract book, The Geological Society of America, Czech Geological Survey (Host Society), Tulsa, OK USA, AAPG Convention Department, 109.

Wainstain L.A., 1963. Fale elektromagnetyczne. PWN, Warszawa, 257-302.



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