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Volume 51 Supplement 10

Special Issue: Electromagnetic Induction in the Earth

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Magnetic distortion of GDS transfer functions: An example from the Penninic Alps of Eastern Switzerland revealing a crustal conductor


We carried out sixty-four MT and GDS soundings in the eastern Swiss Alps to obtain information on the electrical conductivity distribution. One of the main findings is an anomalous directional behaviour of the real induction arrows over the entire period range (T = 1–300; s) on the Bündnerschiefer. The Bündnerschiefer occurs between the crystalline Aar and Gotthard massives to the North and the crystalline Penninic nappes (Adula, Tambo, Suretta) to the South within the investigation area. The sediments form an elongated eastwards plunging ramp with a possible conductive link to the Northern Swiss Permo-carboniferous trough (Molasse basin). We consider electric currents induced in various local and regional conductive structures and leaking into the Bündnerschiefer as possible causes for the observed effect upon the electromagnetic field. Applying Hypothetical Event Analysis (HEA) we find a spatial decoupling of the induction processes with depth and a conductivity anomaly presumably due to the northward indentation by the Adriatic plate.


  • Alfano, L., G. Lorenzoni, C. Melachi, M. Mochi, G. Nuttini, F. Pirera, and M. E. Soffientini, A deep geoelectrical survey in the Southern Central Alps, Ann. Geofisica, XXXVII(5), 1185–1198, 1994.

    Google Scholar 

  • Arora, B. R. and A. Adam, Anomalous directional behaviour of induction arrows above elongated conductive structures and its possible causes, Phys. Earth Planet. Inter., 74, 183–190, 1992.

    Article  Google Scholar 

  • Bahr, K., Magnetotellurische Messungen des Elektrischen Widerstandes der Erdkruste und des oberen Mantels in Gebieten mit Lokalen und Regionalen Leitfȧhigkeitsanomalien, Ph.D. Thesis, G. August Univ., Göttingen, 1985.

    Google Scholar 

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

    Google Scholar 

  • Bailey, R., R. Edwards, G. Garland, R. Kurtz, and D. Pitcher, Electrical conductivity studies over a tectonical active area in Eastern Canada, J. Geomag. Geoelectr., 26, 125–146, 1974.

    Article  Google Scholar 

  • Banks, R. J. and D. Beamish, Local and regional induction in the British Isles, Geophys. J. R. astr. Soc., 79, 539–553, 1984.

    Article  Google Scholar 

  • Berktold, A., Erdmagnetische Tiefensondierung in Süddeutschland und in den Alpen, in Elektromagnetische Tiefenforschung, edited by A. Berktold, pp. 58–70, Deutsche Geophysikalische Gesellschaft, Grafrath/Bayern, 1974.

  • Berktold, A., On the distribution of the electrical conductivity in the area between the Rhinegraben, the Bohemian Massive and the Central Alps, Acta Geodaet., Geophys. and Montanist. Acad. Sci. Hung. Tomus, 13(3–4), 437–440, 1978.

    Google Scholar 

  • Berktold, A., M. Beblo, and K. Kemmerle, On the distribution of the electric conductivity below the Eastern Alps, Geol. Rundschau, 65(2), 715–732, 1976 (reprint).

    Article  Google Scholar 

  • Blohm, E.-K., Ultrabasisches Mantelmaterial: Tiefengeoelektrik beim Ultramafitit-Körper von Finero, 10 pp., Endbericht zur DFG-Sachbeihilfe Bl 131/1. Archiv BGR/Nlfb 77 855, Hannover, 1977.

  • Blundell, D., R. Freemann, and St. Müller, (eds.), A Continent Revealed. The European Geotraverse, 275 pp., Cambridge University Press, Cambridge, 1992.

  • Cassinis, R., F. Federici, A. Galmozzi, and S. Scarascia, A three-dimensional gravity model of crustal structure in the Central-Eastern Alpine sector, Ann. Geofisica, XL(5), 1095–1107, 1997.

    Google Scholar 

  • Coward, M. and D. Dietrich, Alpine tectonics—an overview, in Alpine Tectonics, edited by M. Coward, D. Dietrich, and R. G. Park, 45, pp. 1–29, Geol. Soc. London Spec. Publ., 1989.

  • Fischer, G., The North Pyrenean magnetic anomaly re-examined, Ann. Geophysicae, 2(2), 181–186, 1984.

    Google Scholar 

  • Groom, R. W., The effects of inhomogeneities on magnetotellurics, Ph.D. Thesis, Univ. Toronto, 1988.

  • Groom, R. W. and R. C. Bailey, Analytic investigation of the effect of near-surface 3D galvanic scatters on MT tensor decomposition, Geophysics, 56, 496–518, 1991.

    Article  Google Scholar 

  • Jones, A. G. and R. W. Groom, Strike-angle determination from the magne-totelluric impedance tensor in the presence of noise and local distortion: rotate at your peril!, Geophys. J. Int., 113, 524–534, 1993.

    Article  Google Scholar 

  • Pfiffner, O. A. and L. Hitz, Geologic interpretation of the seismic profiles of the eastern traverse (lines E1–E3, E7–E9): Eastern Switzerland, in Deep Structure of the Swiss Alps, edited by O. A. Pfiffner, P. Lehner, P. Heitzmann, St. Mueller, A. Steck, 380 pp., Birkhäuser Verlag, Basel, 1997.

  • Richards, M. L., U. Schmucker, and E. Steveling, Electrical conductivity in the Urach geothermal area, a geomagnetic induction study using pulsa-tions, in The Urach Geothermal Project (Swabian Alb Germany), edited by H. Ralph, pp. 301–311, Schweitzerbart’sche Verlagsbuchhandlung, Stuttgart, 1982.

    Google Scholar 

  • Ritter, P., Separation of local and regional information in geomagnetic response functions using hypothetical event analysis, Ph.D. Thesis, University of Edinburgh, Edinburgh, 1996.

    Google Scholar 

  • Ritter, P. and R. Banks, Separation of local and regional information in distorted GDS response functions by hypothetical event analysis, Geophys. J. Int., 135, 923–942, 1998.

    Article  Google Scholar 

  • Rokityansky, I., Geoelectromagnetic Investigation of the Earth’s Crust and Mantle, 381 pp., Springer Verlag, Berlin, 1982.

    Book  Google Scholar 

  • Schlunegger, F. R., A. Matter, D. W. Burbank, and E. M. Klaper, Magnetostratigraphic constraints on relationships between evolution of the central Swiss Molasse basin and Alpine orogenic events, Bull. Geol. Soc. Am., 109, 225–241, 1997

    Article  Google Scholar 

  • Schmid, S. M., O. A. Pfiffner, N. Froitzheim, Geophysical-geological transect and tectonic evolution of the Swiss-Italien Alps, Tectonics, 15(5), 1036–1064, 1996.

    Article  Google Scholar 

  • Schmucker, U., Anomalies of geomagnetic variations in the southwestern United States, Bull. Scripps. Inst. Oceanogr., 13, pp. 1–165, Univ. Calif., 1970.

    Google Scholar 

  • Schnegg, P.-A., The magnetotelluric survey of the Penninic Alps of Valais, Matériaux pour la Géologie de la Suisse, 32, 76 pp., Swiss Geophysical Commission, 1998.

    Google Scholar 

  • Steinmann, M., Ein Beckenmodell für das Nordpenninikum der Ostschweiz., Jb. Geol. B.-A, 137(4), 675–721, 1994.

    Google Scholar 

  • Suana, M., Die Manganerzlagerstätten von Tinizong (Oberhalbstein, Graubünden), Beiträge zur Geologie der Schweiz, 64, 92 pp., Schweizerische Geotechnische Kommission, 1984.

    Google Scholar 

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Gurk, M. Magnetic distortion of GDS transfer functions: An example from the Penninic Alps of Eastern Switzerland revealing a crustal conductor. Earth Planet Sp 51, 1023–1034 (1999).

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