Geomagnetic induction studies in Scandinavia — I. Determination of the inductive response function from the magnetometer array data

Main Article Content

A.G. Jones


Data from the Munster IMS Magnetometer Array (Kuppers et al. 1979) have been analysed in the frequency domain to derive the inductive response function, C(ω, 0), from the ratio of the vertical magnetic field to the spatial gradient of the horizontal magnetic field. The response function was best determined by statistical frequency analysis techniques after the spatial gradients had been derived by least-squares fitting of two-dimensional second-order polynomials to the observations, with the constraint imposed that the solutions be curl-free. The derived response function was found to obey two different causality requirements, and most of the inequality constraints imposed on it (Weidelt, 1972). A preliminary model, in which conductivity is a function of depth only and which explains the major details of the observed response, is presented. It has a highly resistive uppermost layer of some 104 Ωm and of the order of 30 km thick, underlain by a layer of about 125 Ωm to a depth of around 140 km, where a transition takes place to a highly conducting (3 Ωm) half space. The effect of various non-uniform sources on the observations of C(ω, k) for this 1D model is illustrated.

Google Scholar           ARK:



Article Details

How to Cite
Jones, A. (1980). Geomagnetic induction studies in Scandinavia — I. Determination of the inductive response function from the magnetometer array data. Journal of Geophysics, 48(1), 181-194. Retrieved from


Baumjohann, W., Greenwald, R.A., Kuppers, F. (1978) Joint magnetometer array and radar backscatter observations of auroral currents in northern Scandinavia. J. Geophys. 44:373-383

Baumjohann, W., Untiedt, J., Greenwald, R.A. (1980) Joint two-dimensional observations of ground magnetic and ionospheric electric fields associated with auroral zone currents. 1. Three-dimensional current flows associated with a substorm-intensified eastward electrojet. J. Geophys. Res. 85:1963-1978

Bendat, J.S., Piersol, A.G. (1971) Random data: analysis and measurement procedures. Wiley-Interscience, New York

Berdichevsky, M.N., Fainberg, E.B., Rotanova, N.M., Smirnov, J.B., Vanyan, L.L. (1976) Deep electromagnetic investigations. Ann. Geophys. 32:143-155

Cagniard, I. (1953) Basic theory of the magneto tell uric method of geophysical prospecting. Geophysics 18:605-635

Champeney, D.C. (1973) Fourier transforms and their physical application. Academic Press, London

Čižek, V. (1970) Discrete Hilbert Transform. IEEE Trans. Audio Electroacoust. AU-18:340-343

Edwards, R.N., Bailey, R.C., Garland, G.D. (1980) Crustal and upper mantle electrical conductivity studies with natural and artificial sources. Geophysics (Submitted)

Ferris, C.D. (1962) Linear network theory. Charles E. Merrill Books Inc., Columbus, Ohio

Fischer, G., Schnegg, P.-A. (1980) The dispersion relations of the magnetotelluric response and their incidence on the inversion problem. Geophys. J. R. Astron. Soc. (In press)

Frazer, M.C. (1974) Geomagnetic sounding with arrays of magnetometers. Rev. Geophys. Space Phys. 12:401-420

Golub, G. (1965) Numerical methods for solving linear least-squares problems. Numerische Math. 7:206-216

Gough, D.I. (1973a) The interpretation of magnetometer array studies. Geophys. J. R. Astron. Soc. 35:85-98

Gough, D.I. (1973b) The geophysical significance of geomagnetic variation anomalies. Phys. Earth Planet. Inter 7:379-388

Gough, D.I., Reitzel, J.S. (1967) A portable three component magnetic variometer. J. Geomagn. Geoelectr. 19:203-215

Hermance, J.F. (1978) Electromagnetic induction m the Earth by moving ionospheric current systems. Geophys. J. R. Astron. Soc. 55:557-576

Hibbs, R.D., Jones, F.W. (1976a) The calculation of the electromagnetic fields of a sheet current source with arbitrary spatial intensity distribution over a layered half-space-I. The general method and results. Geophys. J. R. Astron. Soc. 46:433-452

Hibbs, R.D., Jones, F.W. (1976b) The calculation of the electromagnetic fields of a sheet current source with arbitrary spatial intensity distribution over a layered half space - II. The computer program and its application. Geophys. J. R. Astron. Soc. 46:453-465

Hildebrand, F.B. (1956) Introduction to numerical analysis. McGraw-Hill, New York

Jones, A.G. (1977) Geomagnetic induction studies in southern Scotland. Ph.D. Thesis, University of Edinburgh

Jones, A.G. (1979) New coherence functions useful for determining the signal to random noise ratio in multivariate studies. IEEE Trans. Acoust., Speech, Signal Processing (Submitted)

Jones, A.G. (1980) On the reduction of bias in response function estimation for hand-digitised data. Geophys. J. R. Astron. Soc. (Submitted)

Jones, A.G., Hutton, R. (1979) A multi-station magnetotelluric study in southern Scotland - II. Monte-Carlo inversion of the data and its geophysical and tectonic implications. Geophys. J. R. Astron. Soc. 56:351-368

Jones, A.G., Olafsdottir, B. (1979) Geomagnetic induction studies in northern Scandinavia. Geophys. J. R. Astron. Soc. 57:265

Kanasewich, E.R. (1973) Time sequence analysis in geophysics. University of Alberta Press, Edmonton, Canada

Kuckes, A.F. (1973a) Relations between electrical conductivity of a mantle and fluctuating magnetic fields. Geophys. J. R. Astron. Soc. 32:119-131

Kuckes, A.F. (1973b) Correspondence between the magnetotelluric and field penetration depth analysis for measuring electrical conductivity. Geophys. J. R. Astron. Soc. 32:381-385

Kuppers, F., Untiedt, J., Baumjohann, W., Lange, K., Jones, A.G. (1979) A two-dimensional magnetometer array for ground-based observations of auroral zone electric currents during the International Magnetospheric Study. J. Geophys. 46:429-450

Lilley, F.E.M. (1975) Magnetometer array studies: A review of the interpretation of observed fields. Phys. Earth Planet. Inter. 10:231-240

Lilley, F.E.M., Sloane, M.N. (1976) On estimating electrical conductivity using gradient data from magnetometer arrays. J. Geomagn. Geoelectr. 28:321-328

Mersmann, U., Baumjohann, W., Kuppers, F., Lange, K. (1979) Analysis of an eastward electrojet by means of upward continuation of groundbased magnetometer data. J. Geophys. 45:281-298

Price, A.T. (1962) The theory of magnetotelluric fields when the source field is considered. J. Geophys. Res. 67:1907-1918

Porath, H., Dziewonski, A. (1971) Crustal resistivity anomalies from geomagnetic deep sounding studies. Rev. Geophys. Space Phys. 9:891-915

Schmucker, U. (1970) Anomalies of Geomagnetic Variations in the Southwestern United States. Bull. Scripps Inst. Oceanogr., Univ. Calif. Press 13

Schmucker, U., Weidelt, P. (1975) Electromagnetic Induction in the Earth. Lect. Notes, Aarhus University

Solodovnikov, V.V. (1952) Introduction to the statistical dynamics of automatic control systems. Chapter 1. (Translation edited by J.B. Thomas and L.A. Zadeh, Dover Publications Inc., New York, 1960)

Srivastava, S.P. (1965) Method of interpretation of magneto-tell uric data when source field is considered. J. Geophys. Res. 70:945-954

Untiedt, J., Pellinen, R., Kuppers, F., Opgenoorth, H.J., Pelster, W.D., Baumjohann, W., Ranta, H., Kangas, J., Czechowsky, P., Heikkila, W.J. (1978) Observations of the initial development of an auroral and magnetic substorm at magnetic midnight. J. Geophys. 45:41-65

Weidelt, P. (1972) The inverse problem of geomagnetic induction. J. Geophys. 38:257-289

Weidelt, P. (1978) Entwicklung und Erdprobung eines Verfahrens zur Inversion zweidimensionaler Leitfahigkeitsstrukturen in E-Polarisation. Habilitationsschrift Math.-Naturwiss. Fak. Univ. Gottingen

Westerlund, S. (1972) Magnetotelluric experiments in the range 0.01 Hz to 10 kHz. KGO Report No. 72:10, Kiruna Geophysical Observatory

Woods, D.V., Lilley, F.E.M. (1979) Geomagnetic induction in central Australia. J. Geomagn. Geoelectr. 31:449-458