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Turkish Journal of Earth Sciences

DOI

10.3906/yer-2011-18

Abstract

NW Iran-SE Turkey is a tectonically active zone related to the Arabia-Eurasia convergence, but the active stress state in this zone has not yet been clearly studied. To improve the knowledge of present-day stress state in this region, optimum reduced stress tensor was analysed. For this, a large number of earthquake focal mechanisms (277) were collected. The analyses show most mechanisms exhibit strike-slip to thrust faulting. These data indicate that this region is dominated by an N158° maximum horizontal compressive stress (SHmax) belonging to a transpressional tectonic regime. In the scale of the study area, the relative magnitude of the intermediate and minimum principal stress axes do not differ much (Φ = 0.09). Brittle deformation in this area is dominantly accommodated by a combination of strike-slip and thrust faulting (AΦ = 1.82 to 2.30). The analyses reveal that two sets of faults show a high tendency to slip and reactivate. These sets contain NW-SE-striking right-lateral and NNE-SSW-striking left-lateral faults. The results of this study may help to study the active seismicity, tectonic activity, and seismic risk in this region.

Keywords

Stress inversion, stress regime, focal mechanism solution, active tectonic, NW Iran-SE Turkey

First Page

235

Last Page

246

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