بازسازي تنش كواترنري براساس تحليل لغزش گسل در نيمه جنوبي البرز خاوري

Quateranry Paleostress reconstruction based on fault slip analysis in southerneast Alborz

On the basis of Kinematic findings at different scales in Quaternary fault zones, and using modern methods of fault slip analysis, Quaternary stress field was reconstructed. Orientation of slip plane, slip vector, principal stresses, shape of stress ellipsoid and angle of internal friction are involved the fault slip analysis. Orientations of al , °.2 and Cr3 stresses for primary data (nonrotated) were determined as 084 ° 104 ° , 232 ° /82 ° and 077 ° 108 ° respectively. The shape of stress ellipsoid was defined on the basis of shape factor [R=((02 - cr 3) I(° : - 473 )] (Angelier, 1975). The R-value for all studied regions was about 0.5 and deformation type was mainly left lateral transpressional with small reverse components. Such results are evidence of north trending 6, in the region and northward movement of the crust. The results are in agreement with other methods such as focal mechanisms of earthquakes.