Neotectonics of the Central Kopeh Dagh drainage basins, NE Iran

Abstract

In the Central part of the Kopeh Dagh, there are a set of active right-lateral strike-slip faults that obliquely intersect the range and cause displacement in geomorphological and geological structures. In order to evaluate the rate of tectonic activities in the Central Kopeh Dagh, T, SL, Vf, HI, and RIAT morphometric indices were evaluated. The average value of T index is equal to 0.25, and the main rivers are tilted toward the south. So, the E-W trending folds and thrusts, which are parallel to the basins, have caused the main river to tilt to the south. The highest value of the SL index is related to the intersection of the strike-slip faults which cut the sixth and seventh order rivers. The lowest values of the Vf index are related to the northern part of the studied region; hence, the V-shape valleys and high incision rates are associated with the high degree of tectonic uplift in the Shirinrood basin. Moreover, high values of the SL index and low values of the Vf index are related to the intense tectonic activities in the northern part of the Central Kopeh Dagh. The hypsometric integral (HI) indicates that the highest rock uplifts rate happened in the Shirinrood basin. Neotectonic analysis of the Central Kopeh Dagh shows that the northern part of the study area has the highest tectonic activity and earthquake risk.