Tectonic Stress Variations in the Zagros Using Inversion of Earthquake Focal Mechanisms

Pourbeyranvand, SH; Tatar, M

doi:10.22071/gsj.2015.43385

Tectonic Stress Variations in the Zagros Using Inversion of Earthquake Focal Mechanisms

Document Type : Original Research Paper

Authors

SH Pourbeyranvand ¹

M Tatar ²

¹ Assistant Professor, International Institute of Semiology & Earthquake Engineering, Tehran, Iran.

² Associate Professor, International Institute of Semiology & Earthquake Engineering, Tehran, Iran.

10.22071/gsj.2015.43385

Abstract

Having knowledge of stress variations in the Zagros region, southwest Iran is necessary to study the deformation resulting from oblique collision between the Eurasian & the Arabian plates and to obtain insight into the complicated tectonics of the region. In this study, earthquakes focal mechanism data were used to collect information on the state of stress in 12 subdivisions of the data including teleseismic and local events in the Zagros region. The stress axis show noticeable variations in the Zagros region, especially around the Oman Line. The angular difference between the stress & strain axis increases from the southeast to the northwest of the ZagrosMountain. The deformation partitioning due to pre-existing faults and fractures and introducing a weak zone in the NW Zagros under the influence of the Main Recent Fault activity may explain this increasing.

Keywords

Tectonic Plate Motion

Oman Line

Earthquake

focal mechanism

Fault

Stress Inversion

Zagros