سید رضا منصوری

STUDY OF ORIENTATION OF HORIZONTAL SEISMIC STRAIN COMPONENTS IN THE ZAGROS BELT Tectonic stresses play an important role in the formation and the deformation of the earth's interior. So, the studying of stress changes is one of the best ways to recognize the tectonics and the geology structures in an area. Since the orientation stress depends on the environment so the stress absorption are different in various environments. Hence, the orientation of stresses varies in different locations that are followed by structural deformations. The stress regime that was discussed can be caused by crustal deformation in most places, and resulting in lateral shortening, wrinkle, and orogeny. This deformation can appear as a decrease in the length and height of the crust. The most reduction in the length or maximum strain, which is the crust response to the maximum stress, has been obtained with acceptable accuracy in the same direction as the stress orientation. The Zagros mountains due to the unique tectonic activity, and on the other hand due to tectonic structures and high seismicity and also the presence of major hydrocarbon resources is an important region for the studying the stress/strain distribution. This study is one of the new tectonic methods, which determines the stress orientation by the inversion method and the results are analyzed with the help of the mechanism data. By calculating the horizontal stress orientation, horizontal strain orientation can be achieved in various regions of the Zagros belt. Also, the results can be used to better understanding of the complex tectonic regime prevailing in the region. Through this research, the available data in 21 regions are analyzed. Finally, the results show that the orientation of the horizontal strain in the west and southwest of Zagros has the azimuth between 34 to 57 degrees. Except for the three regions that are not within this range but in the south of Zagros, this direction is nearly 180 degree. The prevailing r