Remarks on Spatial Distribution of Long Period Variations in the Geomagnetic Field over European Area
J. Pecová,K. Pec,O. Praus +2 more
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In this paper, the spectral amplitudes and phases of the 27-day variation and its harmonics over a network of mostly European observatories, but extended to global scale by including some suitably distributed geomagnetic stations on other continents.Abstract:
Geomagnetic observatory data were analysed to obtain the spectral amplitudes and phases of the 27-day variation and its harmonics over a network of mostly European observatories, but extended to global scale by including some suitably distributed geomagnetic stations on other continents. The spectral amplitudes, estimated by different methods, were subjected to spherical harmonic analysis by expanding the geomagnetic potential function into a series of spherical harmonics up to the 2nd order and by calculating the corresponding coefficients. The contours of the H and Z components were then calculated to analyse their latitude-longitude dependence over European area. The moduli of electromagnetic response functions estimated from global data for individual harmonics were compared with the results obtained previously for European data only. The distribution of deviations of (Z/H) ratios defined by differences between the actual data and the theoretical fits were investigated. Using the theoretical basis of electromagnetic induction in stratified conductors, we estimated the depths of a perfect substitute conductor at those depths from characteristics of the 27-, 13-, and 9-day variations.read more
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Journal ArticleDOI
The deep electrical structure of the Earth
TL;DR: In this paper, two different onedimensional inversion techniques are used to estimate the variation with depth of conductivity at depths between 300 and 1000 km beneath 17 locations which are scattered world-wide but concentrated in Europe.
Journal ArticleDOI
Lateral variations of the mid-mantle conductance beneath Europe
V. Yu. Semenov,W. Jozwiak +1 more
TL;DR: In this paper, a geomagnetic induction data set from 35 European observatories was used to estimate the geomagnetism response functions for various period ranges, typically of the width of 1.5 to 2.5 decades, and the combined responses were inverted individually for each observatory by an Occam procedure and a stochastic 1D inversion for spherically symmetric Earth.
Journal ArticleDOI
Global electromagnetic induction
TL;DR: In this article, the authors reviewed the effect of lateral inhomogeneity within the Earth and proposed an inversion of response function data to produce conductivitydepth profiles, and aspects of the inverse problem specific to global (spherical Earth) induction are discussed.
Journal ArticleDOI
Electrical conductivity structure in the lower crust
TL;DR: In this paper, the relationship between the electrical conductivity information and other types of geophysical and geological information for each geographical area investigated is investigated, and partial conclusions by different authors, using different methods and referring to different geographical regions, into a working scheme.
Book ChapterDOI
Appreciation of spherically symmetric models of electrical conductivity
TL;DR: In this article, a spherically symmetric model of the electrical conductivity of a radially inhomogeneous Earth has been proposed to solve the inverse problem of electric conductivity.
References
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Book
Anomalies of geomagnetic variations in the Southwestern United States
TL;DR: A survey with temporary geomagnetic field stations (Askania Variographs) has been conducted in the southwestern United States in order to study local differences of geOMagnetic variations as discussed by the authors.
Journal ArticleDOI
Geomagnetic Variations and the Electrical Conductivity of the Upper Mantle
TL;DR: The electrical conductivity of the upper mantle can be determined by comparing the measured response of the Earth to magnetic variations of all frequencies with the theoretical response of particular conductivity distributions as mentioned in this paper.
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