Geomagnetic induction studies in Scandinavia — I. Determination of the inductive response function from the magnetometer array data
Main Article Content
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.
Authors who publish with this journal as of Vol. 63 agree to the following terms:
a. Authors share the copyright with this journal in equal parts (50% to the journal, 50% to the lead author), and grant the journal right of first publication, with the work after publication simultaneously licensed under Creative Commons Attribution License CC BY-NC-ND 4.0 that allows others to share the work with an acknowledgment of the work's authorship and initial publication in this journal.
b. Authors may enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgment of its initial publication in this journal, and a reference to this copyright notice.
c. Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) during the submission process, as this can lead to productive exchanges and earlier and greater citation of published work and better sales of the copyright.
Authors retain copyright and grant the Journal of Geophysics right of first publication, with the work three years after publication simultaneously licensed under the Creative Commons BY-NC-ND 4.0 License that allows others to share the work (with an acknowledgment of the work's authorship and initial publication in this journal), except for commercial purposes and for creating derivatives.
Authors can enter into separate, additional, but non-commercial contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository, but not publish it in a book), with an acknowledgment of its initial publication in this journal.
Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) before and during the submission process, as that can lead to productive exchanges, as well as earlier and greater citation of published work (See The Effect of Open Access).
This journal is one of a handful of scholarly journals that publish original scientific works under CC BY-NC-ND 4.0 - the only Creative Commons license affording the authors' intellectual property absolute worldwide protection.
Journal of Geophysics is published under the scholar-publishers model, meaning authors do not surrender their copyright to us. Instead, and unlike corporate publishers like Elsevier or Springer Nature that resell copyright to third-parties for up to $80,000 (per paper, per transaction!), the Journal of Geophysics authors share copyright equally with this journal.
Therefore, all the proceeds from reselling copyright to third parties get shared to equal parts (50% to the journal, 50% to the lead author). Under the Berne Convention, this protection is an inheritable right that lasts for as long as the rightsholder lives + 50 years.
By submitting to this journal, the lead author, on behalf of all co-authors, grants permission to this journal to represent all co-authors in negotiating copyright sales and collecting proceeds. The lead author should negotiate with his/her co-authors the modalities of distributing the lead author's portion of the proceeds. Usually, this is per pre-agreed percentage of each co-author's contribution to creating the copyrighted work. (more...)
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