Analysing of tectonic activity, Farahzad basin using geomorphic indicators

In the present age the parts of the earth's crust have tectonic movements and in the future will be more prone to risk. Geomorphological processes and also forms is very sensitive to the tectonic activity and changes by this motion. The assessment of tectonic activity using by some indicators have a major role in identifying these activities and helps to interpret the tectonic regions. Research In this study for the determination of tectonic activity in Frahzad basin in the north western of metropolitan Tehran, using and calculating geomorphic indices such as Stream length gradient index (Sl), Valley floorvalley height ratio (Vf), Asymmetric factor (Af), Topographic inversion symmetry (T), Drainage basin shape ratio (Bs), and meandering rivers (S). The research procedure is based on analytical method. The Physical and conceptual tools of this research are the topography and geology maps of the study area, satellite images and GIS software, in the form of ARC GIS 10 and several field visits from landforms, has been used. Discussion and This basin, with an area equivalent to 35,8 kilometers, one of the subbasins of the mountain range north of the Tehran metropolis, according to range of processes (mainly sliding and falling), is suitable for the assessment of relative tectonic activity. The results indicate that the farahzad basin based on indicators of the Sl, Vf, Af, T and S in active status and Semi-active status is measured according Bs. Analysis of these quantities represent the activity of the basin in the present age and the average tectonic activity based on IAT index (Index of relative active tectonics) puts this basin in the class 1. The results correspond with the geomorphological evidence (landslide occurrence).