Evaluation of Morphotectonic Indices in Qangholichay Basin

Neo-tectonic is of dynamic factors which always affects on the watersheds and rivers. Neo-tectonic is said to the new tectonic factors which mainly reflects in the faults. Displacement of faults can trigger the epicenters of the earthquake, the release of earth internal forces and deformation of geomorphological factors of the land surface. The aim of this study is to investigate the tectonic situation of Qanqholichay basin, which Rudbar and Manjil earthquake landslide in 1990 was formed Lake Baklur in this basin. For this purpose, with the help of Arc GIS, Global Mapper 12,softwares and by using relative morphotectonic indexes such as slope length of river (SL), asymmetric factor (Af), integral hypsometric curve (Hi), valley floor width-to-height ratio (Vf), basin shape (Bs), Mountain-front sinuosity (Smf), transverse topographic (T) and sinusoidal of river (Sr), such activities have been reviewed According to the results of this study, SL, SMF and SR indices show the youngness of the basin in terms of erosion cycle of the area. The activity of faults of PoshteKuh and Manjil perpendicular on the basin caused the height difference and a distinguished change in longitudinal profile of Qangholichay Basin and SL index. Other indices represent the average tectonic activity of the basin. The great tectonic activity of the basin from the view of Relative Land form Active Index ( LAT), shows that each of such indices can not lonely specify the tectonic situation of the basin, and LAT index shall be estimated for all the basins, which on its basis, the basin will be placed at class 2 i.e. with a high tectonic activity. Use of non-dimensional chart is so useful in approval of tectonic activities of the basin especially for SL index. Based on its interpretation, it can be said that Qangholichay Basin is active from tectonic view.