Sources of recent tectonic stress in the Pannonian region: inferences from finite element modelling

We present the results of finite element modelling of the recent stress field in the Pannonian basin and surrounding Alpine orogenic belt. Our results show that the recent, predominantly compressive, stress regime in the Alpine-Pannonian-Carpathian-Dinaric system is governed by distinct tectonic factors. Of great importance is the deformation of crustal blocks with different geometries and rigidities in an overall convergent setting associated with the Africa-Europe collision. The most important stress source appears to be the counterclockwise rotation of the Adriatic microplate at the southwest boundary of the Pannonian basin. This plate tectonic unit has been interpreted as moving independently of both the European plate and the African plate. Additional boundary conditions-active: shortening and compression in the Vrancea zone and the Bohemian Massif, and the effect of the immobile Moesian Platform-also significantly influence the modelling results. The incorporation of additional stress sources such as crustal thickness variation and the presence of two main fault zones separating the primary tectonic units in the study area have only locally important effects but improve the fit between the calculated results and the observed stress pattern.