Estimating rate of tectonic activity in central Kopeh dagh using morphometric indices

Abstract

In central part of Kopeh dagh there is an array of active right-lateral strike-slip faults that obliquely cut the range and produce offsets of several kilometers in the geomorphology and geological structure. Geomorphic indices indicate the presence of differential uplifting in history of this area. Tectonic activity of the study area is investigated by a large number of DEM derived catchments and drainage lines using GIS: ratio of valley floor width to valley height, stream length-gradient index, transverse topographic system, hypsometric integral, drainage basin shape and sinuosity. The recent investigations show that west part of Yekehshakh basin is active part and morphotectonism has played a key role in the geomorphic evolution of this part of the Kopeh dagh mountain range. Low value of V_f index and high value of SL index is related to west of basin. Calculating morphometric indixes for Yekehshakh basin's show that, value of T index is 0.25 and direction of tilting is toward S. Geomorphic indices indicate the presence of differential uplifting was happened in past. The west of study area shows very high relative tectonic activity.