Relative Assessment of Tectonic Activities, Upper Kangir Basin (Eyvanegharb) UsingGeomorphic Indicators

During recent years, various researchers tried to quantify the tectonic movements and have presented several indicators as geomorphic indices. Using these indicators provides the possibility for proper analysis of the evolution situation of the drainage network and changes of the mountain front due to the tectonic activities. Kangir basin (Eyvanegharb) is located at coordinates of geographical longitude of 46ْ, 17َ, and 11ًup to east 46ْ, 27َ, and 35ً and geographical latitude 33ْ, 41َ, and 14ًup to north 33ْ, 50َ, and 57ً with an area of122. 71square kilometers in southeast Eyvanegharb city (North of Ilam Province). The only drainage of this basin is Kangir River, which drains the total of Eyvanegharb plain. The main purpose of this paper is the relative evaluation of status of the basin active tectonics through using and calculating geomorphic indices such as Valley floor – valley height ratio (Vf), Asymmetric factor (Af), Stream length gradient index (Sl), Drainage basin shape ratio (Bs), Percentage dissected mountain fronts (Fd), Percentage undissected escarpments (Eu), Mountain front sinuosity (Smf), and Mountain front facet (Fmf). Thus, topographic maps and geology, satellite imagery and geographical information system software in Arc GIS 10 and several field visits from landforms, has been used. The results indicate that the Kangir watershed has a relatively active tectonic status; Based on indicators of Vf, Af, Sl, Fd, Eu, Smf and Fmf, this basin is placed at class one. The amount of qualitative calculated indices is matched with the existing Geomorphologic evidences available in the area such as the V-shaped and deep valleys, escarpments fault, triangular surfaces, young anticline, low cut mountains front, tilt the main drainage and lack of foothills.