Characterization of seismogenic zones of Romania

Although the time and magnitude range covered by available seismological da ta is limited, several significant regional trends are outlined in the seis mogenic zones of Romania. Vrancea region, which is by far the most seismica lly active area, has a persistent rate of occurrence of intermediate-depth earthquakes, clustered in a very confined focal volume, and a clear compres sive stress regime. The deformation field, as deduced from the available fa ult plane solutions, is drastically reduced in the crust, where the maximum magnitude is below 6.5 (except Shabla zone, in Bulgaria). The system of ma jor faults developed in a NW-SE direction in the Carpathians foredeep area is certainly linked to the subduction process in Vrancea, although they see m not to play a significantly active role, as could be expected for an acti ve subduction process. The existing data indicate an extensional deformatio n regime over the foredeep area and Southern Carpathians, while a predomina nt compressive regime is outlined at the contact between the eastern margin of the Pannonian Depression and Carpathians orogen, in agreement with the bending tendency of the maximum horizontal compression orientation of the c rustal stress field from NE-SW, in western and central Europe, to E-W, in t he intra-Carpathian region (GRUNTHAL and STROMEYER, 1992).