بررسي ريخت زمين ساخت و لرزه زمين ساخت پهنه گسلي راور، جنوب ايران مركزي

The ^Tectonic Geomorphology and Seismotectonics of the Ravar Fault Zone, South of Central Iran

According to potential of the intra-continental strike-slip faults for occurrence of large earthquakes, which are also considered as the main elements of active continental deformation, determination of their geometry and kinematics along with recognition of the active segments and temporal structural evolution is necessary. The oblique-slip fault of Ravar with about 137 km length is extending in vicinity of Ravar, north of Kerman. In the north of study area, the fault extends parallel to the Lakar-Kuh fault, but in the south converges toward to the Lakar-Kuh and the Kuh-Banan faults. Upthrusting of the eastern block of the Ravar fault and east-ward thrusting of the LakarKuh fault system constructed a positive flower structure. The motion of the Ravar fault have caused the dextral displacement and an accumulative horizontal displacement of the drainages about 940-970 in the north since Pleistocene. Regarding a minimum horizontal slip-rate of about 0.54 mm/yr, the recurrence time of earthquakes with Mw~ 6.7 would be about 1400 year. In the middle part of the fault, the Reidel fractures of R, Rl, and P has been well developed and caused a dextral deflection of the Esmail-Abad River about 16m. With assumption of characteristic earthquake occurrence, the maximum slip per event could be about 0.75 m, which is consistent with the minimum displacement of the recent gorges. The amount of horizontal dextral displacement of the fault decreases toward to the south, whereas the vertical component of the fault motion increases, so that the Pleistocene deposits show about 10 m difference in elevation across the southern part of the fault. Concerning the trend of meizoseismal zone of 1911/04/18 Ravar earthquake (M~ 5.8,10~ VIII) and parallelism of trend of the co-seismic surface rupture (N13W) with the southern part of the fault, the Ravar fault could be responsible of this earthquake. In addition, the active cross- faulting of the Dehu, the Dehzanan, the Chatrud, the Pasib, and the Darbid-Khun control the recurrence time and magnitude of the earthquakes in the study area. Keywords: Strike-slip faults, Segmentation, Active fault, Tectonic geomorphology, The Ravar fault zone, Central Iran For Persian Version see pages 57 to 66 Corresponding author: A. Shafiei Bafti; E -mail: Amir.Shafii@gmail.com