In 1998, the Geophysical Exploration Company and the State Geological Institute of Poland started broad-scale magnetotelluric (MT) investigation in the Polish Carpathians. The measurements were made with the use of the MT-1 system designed and produced by Electromagnetic Instruments, Inc., over a frequency range of 300–0.0005 Hz, with remote magnetic reference applied. The results of data interpretation provided new elements in the recognition of the structure of the flysch orogen and its basement and confirmed earlier interpretation of the roof of the high-resistivity horizon.

A considerable resistivity differentiation was observed in the Mesozoic, Paleozoic, and Precambrian formations in the northern part of the cross sections, where the high-resistivity platform-type basement occurs beneath the autochthonous Miocene sediments. The zone of low-resistivity rocks occurs in the Outer Western Carpathians. The great differences in resistivity distribution are observed in the deep basement along the general axis of the flysch orogen in the southern part of the study area. The results along two MT sections and from three detail areas are presented. The general features of the Carpathian basement interpreted from MT sounding data are different for the eastern and the western part of the study area. Low-resistivity complex and overthrust zones are characteristic of the eastern part of the area. The geological identification of the low-resistivity layer is still not clear.