Geoelectrical Structure of the Earth’s Mantle in Pannonian Basin

Abstract

Data from four geomagnetic observatories: Nagycenk, Tihany, Hurbanovo and Wien-Kobenzl together with magnetotelluric data obtained at 4 points situated not far from these observatories were analyzed to estimate the geoelectrical mantle structure in the Pannonian Basin. Response functions were estimated in the period range from seconds to several hours by the MT method and from 3 days to 1 year by using Dst variations. The published responses obtained from Sq variations were added to remove gaps between MT and MV curves. These deep soundings have confirmed that the upper mantle conductance below the Pannonian Basin is at least twice higher than below the Canadian and Ukrainian shields. The asthenosphere was detected with a conductance of about 4 kS at 80–280 km depths. A conductive zone (20 kS) was required by inversions at the depth of about 500 km. The mid mantle conductive zone was estimated to 550 kS at 850 km depth.