Deep structure of the Tatra Mountains border faults (Western Carpathians): insights from magnetotellurics and gravimetry

Abstract

The knowledge of geological structures and mainly tectonic dislocations (faults) affects various areas of problems (seismic risks, slope deformations, radon emanation and others) and provides important information about the tectonic development of the studied area. The multidisciplinary research of geophysical and structural parameters has been carried out within the framework of the DISLOCAT project, with a focus on the Western Carpathians. This work focuses on refining the position and deep course morphology of the faults that delineate the Neogene horst of the Tatry Mountains, utilizing the magnetotelluric (MT) method and gravimetric map analysis. MT measurements with subsequent 3D modelling were carried out in three areas to image the faults structures in the western, central, and eastern parts of Tatry Mountains. In all sections through the 3D MT models and in the density models, the principal Tatry Fault, which bounds the Tatry Mountains from the South and SE, was identified in its current form as steep, or gently dipping to the south, suggesting that it is a normal fault. The slight displacement of the fault's position into the Tatry massif in its eastern part, relative to its location on geological maps, is likely caused by inaccuracies due to the overlaying fluvioglacial Quaternary sediments. The NE continuation of this fault appears unclear, and it seems to be truncated by EW trending faults that are indicated in the north part of the Tatry Mountains. These faults emerge between the cover and Mesozoic nappe units. Another parallel EW fault was identified north of the massif in the Paleogene fill.