Stress Studies Using 3D Seismic Interpretation Results and Earthquakes in a Gas Field, Southern Iran

Paleostress studies play a major role in understanding of the geodynamics and tectonic evolution of the earth’s crust. In this study, the paleostress history of and area covering an oil fields in Southern Iran, where the usual outcrop data for paleostress studies was not available so far, has been revealed by using 3D seismic interpretation results. The strike and dip of the fault planes extracted directly from the triangles consisting the 3D model of the fault plane while a new method implemented to estimate slip direction from seismic interpretation data. The Allan lines were used to extract the separation data for each horizon and the slip direction calculated from heave and through of the separation pairs. To compare the paleostress direction with the present state of the stress in the study area, the stress tensor inversion performed on the fault plane data from available earthquake focal mechanisms from the Global CMT project. A significant clockwise rotation from older layers up to the younger ones and finally the present day state of the stress was observed. The starting point of the rotation coincides with the initiation of the collision between Arabia and Eurasia which affected the SHmax direction at Eocene time.