Quantity Evaluation of Neotectonic with Emphasis on Geomorphic Evidence in Rijab Area

The Rijab area with189 square kilometers is located in northwest of Zagros and north of Sarpol zahab city. Its main skeleton is made of hard and resistive layers of Shahbazan dolomite and Asmari lime، that its eastern part is pressed as an anticlinorium form but its western part as a syncline form. As a result of Kerend fault Practice most of the tectonically activities are seen in middle parts that its consequence is the displacement of the lime –dolomite layers in the syncline area from the northeast and slanting to the southwest side and breaking occurrence in southwestern belt peak of syncline the bend process has caused breaks that result in turning displacement of broken pieces. This event causes the formation of a series of longitudinal and latitudinal faults، which cut the Rijab syncline lime –dolomite formation in different directions. To determine the neotectonic activities two comparative and interpretive methods have been used in this research، and with the use of ARC GIS software topography maps comparison and interpretation، hydrographic break and aerial images of the area were done by geomorphology forms maps، than it was analyzed by SPSS software. For quantity evaluation of neotectonically activities the following scales have been used: the of non-synchronic drainage area (AF)، the ratio width of valley bed to its height (VF)، the sinus scale of mountain (SMF)، the reversed synchronic topography scale (T)، and classification scale (LAT)، the river longitudinal slope (SL). Then it has continued by studying the role of breaks، clefts، and gaps in formation and developing pattern of floodways by using Golesorkhi chart. Based on the obtaining results the eastern part of the area that it builds on anticlinorium form is tectonically semi – active، western part active and middle part that has syncline structure is very active. Keywords: Neotectonic، Geomorphic Index، Geomorphologic Evidence، Northwestern Zagros، Rijab Area