Main Article Content
Spherical harmonic analysis coefficients of the external and internal parts of the quiet-day geomagnetic field variations (Sq), separated for the North American, European, Central Asian and East Asian regions, were used to determine conductivity profiles to depths of about 600 km by the Schmucker equivalentsubstitute conductor method. All three regions showed a roughly exponential increase of conductivity with depth. Distinct discontinuities seemed to be evident near 255-300km and near 450-600km. Regional differences in the conductivity profiles were shown by the functional fittings to the data. For depths less than about 275 km, the North American conductivities seemed to be significantly higher than the other regions. For depths greater than about 300 km, the East Asian conductivities were largest.
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 as well as earlier and greater citation of published work and better sales of the copyright.
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 absolute worldwide protection of authors' intellectual property.
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 which resell the copyright to third-parties for up to $80,000 (per paper, per transaction!), the Journal of Geophysics authors share the copyright equally with this journal.
Therefore all the proceeds from reselling the copyright to third parties are shared to equal parts as well (50% to the journal, 50% to the lead author). Under the Berne Convention, this protection is an inheritable right which 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 of 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...)
Banks, R.J. (1969) Geomagnetic variations and the electrical conductivity of the upper mantle. Geophys. J. R. Astron. Soc., 17:457-487
Campbell, W.H., Anderssen, R.S. (1983) Conductivity of the subcontinental upper mantel : An analysis using quiet-day geomagnetic records of North America, J. Geomagn. Geoelectr., 35:367-382
Campbell, W.H., Schiffmacher, E.R. (1985) Quiet ionospheric currents of the Northern Hemisphere derived from geomagnetic field records. J. Geophys. Res., 90:6475-6486
Chapman, S., Bartels, J. (1940) Geomagnetism. Clarendon Press, Oxford
Dziewonski, A.M., Anderson, D.L. (1981) Preliminary reference Earth model. Phys. Earth Planet. Inter., 20, 297-356:1981
Lahiri, B.N., Price, A.T. (1939) Electromagnetic induction in nonuniform conductors and the conductivity of the Earth from terrestrial magnetic variations. Phil. Trans. R. Soc. London, A237:509-540
Pollack, H.N., Chapman, D.S. (1977) The flow of heat from the Earth's interior. Seis. Am. 237:60-76
Schmucker, V. (1970) An introduction to induction anomalies. J. Geomagn. Geoelectr., 22:9-33
Schmucker, V. (1979) Erdmagnetische Variationen und die elektrische Leitfahigkeit in tieferen Schichten der Erde. Sitzungsber. Mitt. Braunschw. Wiss. Ges., 4:45-102
Shankland, T.J., Waff, H.S. (1977) Partial melting and electrical conductivity anomalies in the upper mantle. J. Geophys. Res., 82:5409-5417