Neotectonic stress field and deformation pattern within the Zagros and its adjoining area: An approach from finite element modeling

Abstract

In this study, finite element modeling (FEM) is performed to analyze the Neotectonic stress field of Zagros fold-and-thrust belt and its adjoining areas. Our modeling results predict that the study area has somewhat complex stress orientation, deformational fashion and faulting pattern under oblique convergence tectonic setting. The modeled results demonstrate that the displacement vectors within the Coastal plain, Persian Gulf, eastern part of Sanandaj-Sirjan-Metamorphic Zone have NE-ward direction, while the Main Recent Fault and some part of Sanandaj-Sirjan-Metamorphic Zone have N-ward and sometimes NE-ward direction. The modeled maximum horizontal compressive stress (σHmax) orientation within the Lurestan, High Zagros Fault, Main Recent Fault and eastern Zagros Simple Folded Belt are predicted to have NE-SW, NW-SE and N-S, whereas the rest part of the study area displays mainly NE-SW. Fault pattern calculation of the study region predicts that strike slip faults are mainly present at shallow crustal level (up to 10 km), whereas thrust faults with strike-slip component are predominant at deeper crustal level (>10 km). Our modeling results are comparable with available data of focal mechanism solution, seismicity, GPS and world stress map (WSM). Thus we believe that modeling results can be used as a reference dataset, presenting to estimate overall stress condition, plate velocity and faulting pattern of an extensive area, because the other geophysical/geodetic data do not cover wide area of the region. Key words: Zagros fold and thrust belt, stress, focal mechanism solution, seismicity.