Paleomagnetic Secular Variations: statistical properties of real data

Category: 15-4
A.V. Khokhlov


UDC 550.384.3, 519.246.3, 519.258



A.V. Khokhlov


Institute of Earthquake Prediction Theory and Mathematical Geophysics of the Earth, RAS,

Moscow, Russia


Abstract. To understand the nature of the paleomagentic field variations a mathematically rigorous method of testing statistical hypotheses on real paleomagnetic data is required. The lava paleomagnetic data are sparse in time and space, and contain only partial and inaccurate information about the ancient magnetic field vectors. Theoretical descriptions of field variations operate the global parameters that related to the expansion coefficients of the magnetic potential in spherical harmonics (i.e. Gauss coefficients); such a global description allows to specify the vector field at any point of the earth's surface.

     An accurate calculation of the field potential is not achievable from only small, set of data fields (for instance, when all the data belong to one region) so a direct comparison between the observable gauss coefficients and the theoretic ones (that is, from a statistical hypothesis of secular variations) seem difficult.  The more appropriate question: whether the globally modeled field is compatible with the paleodirections from different site locations. Here the compatibility should be treated in statistical sense and the direct implementation of this test is sophisticated as the directions are not the numerical values and therefore the usual statistical approach fails. This article presents the new method of testing the consistency of paleomagnetic secular variations and paleomagnetic data, together with the results of application to Brunhes paleomagnetic real data


Keywords: paleomagnetism, paleosecular variations, Gaussian random process, statistics on spheres. 



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