Risk faults in stable crust of the eastern Bohemian Massif identified by integrating GNSS, levelling, geological, geomorphological and geophysical data

Abstract

It is difficult to identify and assess the recently active faults, representing a risk factor for key human activities, in the areas of stable crust with slow tectonic deformation and reduced seismicity. We face the problem in the eastern Bohemian Massif (Central European Variscides) at a contact with the Eastern Alpine - Western Carpathian orogenic belt through building its integrated geodynamic model based on the long-term GNSS data cross-checked with the results from existing levelling, geological surveys, geophysical surveys, and a new geomorphological analysis. The model shows differently moving crustal blocks, determining the intervening boundary zones as the main risk regions, where weak earthquakes are also usually concentrated (primarily Diendorf-Cebin Tectonic Zone, Nectava-Konice Fault, Hand Faults, Bela Fault and Bulhary Fault Shear Zone). The maximum horizontal GNSS differential velocities in the exposed Bohemian Massif reach up to 1.5-2.0 mm.yr(-1). The up-thrusted segments of the Western Carpathians move individually similar to 2 mmyr(-1). The integration of a number of full-area datasets, corresponding to various dimensions and depth levels of crustal processes, allowed us to highlight the important fault zones as driving elements of regional geodynamics.