An Estimation of the Variation in the Depth of the Sharp Rise in Conductivity Beneath Europe

Research Report MRR99-015

An Estimation of the Variation in the Depth of the Sharp Rise in Conductivity Beneath Europe

H. F. Petersons and S.-A. Gustafson

Abstract: Calculation of the depth z to the perfect substitute conductor beneath Europe for the 34.15 day geomagnetic variation by Petersons and Anderssen (1990) indicated a general increase in z the further southward a magnetic observatory is situated. If the electrical conductivity is known then a more reliable estimate of the depth can be obtained. Globally estimated conductivity values are used in order to obtain what may be better estimates of the depth d to a conducting sphere. The variation in d is found to be in general qualitative agreement with that expected as a result of plate motions, apart from an anomaly beneath the Baltic states, but the d values for the northern observatories are unexpectedly low. Such a qualitative agreement would indicate that subduction causes an increase in the depth to highly conductive material and a decrease in the depth some way away from the subduction. A more detailed study may reveal the reasons for the unexpected low d values for the northern observatories.

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Download paper:	PDF file (22K)
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Download cover sheet:	PDF file (51K)
	DVI file (2K)