EFFECT OF DEEP-REACHING TECTONICS ON CONDUCTIVITY STRUCTURE IN THE PANNONIAN BASIN - CAN MAGNETOTELLURIC DATA CONSTRAIN TECTONIC INTERPRETATIONS

Magnetotelluric (MT) deep soundings carried out along the Pannonian Geotraverse detected anomalous conductivity structures below the narrow Szolnok flysch belt, with a characteristic width of about 20 km, both in the lower crust and the upper mantle. Here seismic investigations determined a strike-slip zone, the main fault zone of which penetrates below the Mohorovicic discontinuity to a depth of 35-40 km. Although the similarity in these two independent tectonic indications is high, the change in the conductivity structure is questioned, and is studied from the point of view of MT field distortions. It is concluded that the resolving power of MT methods is strongly reduced by the geologic noise, and so the tectonic interpretation of deeper horizons becomes uncertain.