Abstract

There are many valleys in the city of Zanjan and Eijrood and parts of Abhar, Tarom and Mahneshan Zanjan province. The valleys are very different in terms of geology, lithology and physiographic factors and they are dispersed in different directions geographically with different forms. First the valleys were classified according to geological structure; totally 149 valleys was identified, 37 valleys had a structure of perpendicular to the fault, 9 valleys faulty and perpendicular to the syncline in parallel structures the fault, 6 valleys in a parallel structure with the fault, 5 valleys in a mixed structure of the fault with syncline or anticline (the mixed valleys) and the remained valleys 64, were classified as "the other valleys". Then tectonic-geomorphologic indexes were used, such as the longitudinal gradient of the river (SL), asymmetry of drainage,(AF), the index of Width of valley floor to its height (VF) and the index of maze in rivers (S), to determine the amount of neotectonic activities of the valleys. The results show that the Average Index (VF) is between one and two in the area of hybrid and perpendicular to the fault, they have semi-active and active tectonics in other classes. The entire region is active with tectonics in Index (AF) and due to the symmetry of the drainage basin. The low index (S) in all classes is the indication of young and active area and straight rivers. All sub-systems based on faults are active tectonic in all indexes. Valleys indicated as "other" are less effected by Neotectonic.