Vol.:(0123456789) Acta Geodaetica et Geophysica https://doi.org/10.1007/s40328-018-0228-x 1 3 ORIGINAL STUDY Probing tectonic processes with space geodesy in the south Carpathians: insights from archive SAR data Eszter Szűcs 1  · István Bozsó 1  · István János Kovács 1  · László Bányai 1  · Ágnes Gál 2  · Alexandru Szakács 3  · Viktor Wesztergom 1 Received: 7 June 2018 / Accepted: 23 July 2018 © Akadémiai Kiadó 2018 Abstract The Carpathian bend is amongst the tectonically most active areas in Europe where intra- plate subduction triggers sub-crustal earthquakes releasing signifcant amount of seis- mic energy in a well-defned seismic zone. To constrain the deep processes by exploiting their linkage to the surface processes an accurate knowledge of surface deformations is required. Detection of small-magnitude tectonic processes with high reliability is a chal- lenge in which the recent space geodetic techniques may bright a breakthrough. In this study we used the archive ENVISAT data set of the European Space Agency to investigate the feasibility limit of detecting crustal deformations in the region of the south Carpathian bend, where past geodetic observations failed to unravel the tectonic processes with high details. Despite the inherent limitations of radar interferometry our results show that coher- ent velocity feld can be estimated with a magnitude of few mm/year. The vertical displace- ment feld suggests subsidence in the Brasov basin which is in agreement with former stud- ies, however radar interferometry can provide a more detailed picture. Keywords Geodynamics · Vrancea zone · Radar interferometry · ENVISAT 1 Introduction The inner Carpathian bend is one of the most exciting part of the European lithosphere where, from time to time, large magnitude intermediate depth earthquakes occur far from the plate boundaries. Although there have been several eforts to couple the ongoing deep- earth processes to deformation pattern via the interpretation of diferent kind of geophys- ical observations and numerical modelling, the geodynamic model of the region is still unclear (Ismail-Zadeh et al. 2012). The internal part of the bend is interesting because of the recent volcanic and post-volcanic activities (Harangi et al. 2015), which is related to * István Bozsó bozso.istvan@csfk.mta.hu 1 MTA CSFK Geodetic and Geophysical Institute, Sopron, Hungary 2 Babeș-Bolyai University, Cluj-Napoca, Romania 3 Institute of Geodynamics, Romanian Academy, Bucharest, Romania