Pliocene to Quaternary stress field change in the western part of the Central Western Carpathians (Slovakia)

Abstract

Knowledge of the current tectonic regime plays an essential role in natural hazard assessment, especially in the risk assessment of fault activity. Structural analysis of brittle deformations (using inversion techniques) was used to determine the stress field state occurring within Pliocene and Quaternary deposits in the western part of the Central Western Carpathians. The deformation pattern of the reduced stress tensor showed that all structural measurements could be separated into two groups. An older, Late Pliocene fault population was activated under NNW-SSE oriented extension. A younger, Quaternary fault population reflected origin in a NE-SW extensional tectonic regime and it distinctly showed a change the orientation of the S3 of about 70°. The change in tectonic activity, as well as in the stress field orientation, is dated to the Pliocene-Pleistocene boundary. The Quaternary stress field developed during the post-collisional stage of the orogen. Our study shows that the Western Carpathian internal units document NE-SW to NNE-SSW extension in the broader region around of the northern Danube Basin.