Morphotectonic evaluation in the epicenter region of the Khurgu 21.3.1977 earthquake (Eastern Zagros, south of Iran)

   Abstract:
      Morphotectonic evaluation in the epicenter region of the Khurgu 21.3.1977 earthquake shows this event had been associated to shortening basement and sedimentary cover along Mountain Front Fault and Khurgu ramp respectively. These two faults and gap between them have important roles in constructing of earthquake sources geometry. The region has been affected from NNW shortening due to Makran convergent subduction zone, but the presence of thick detachment surfaces and thick clastic sediments (Aghajari & Bakhtiary formations) lead to dominating of faulting so Khurgu anticline has along wavelength and has a hidden ramp in its core. A field investigation, which has been carried out emphasizing of satellite images and aerial photos interpretations, shows Khurgu 1977 earthquake had not associated to primary rupture and the event could be related to vertical segmentation along mountain front fault segments.

   General:
     Morphotectonic evaluation in the epicenter region of the Khurgu 21.3.1977 earthquake shows this event had been associated to shortening basement and sedimentary cover along Mountain Front Fault and Khurgu ramp respectively. These two faults and gap between them have important roles in constructing of earthquake sources geometry. The region has been affected from NNW shortening due to Makran convergent subduction zone, but the presence of thick detachment surfaces and thick clastic sediments (Aghajari & Bakhtiary formations) lead to dominating of faulting so Khurgu anticline has along wavelength and has a hidden ramp in tis core. A field investigation, which has been carried out emphasizing of satellite images and aerial photos interpretations, shows Khurgu 1977 earthquake had not associated to primary rupture nad the event could be related to vertical segmentation along mountain front fault segments