بررسي مورفولوژي پرتگاه ها و تحول پسروي جبهه شمالي توده كوهستاني الوند

The Analysis of Cliff Morphology and Retrogressive Transformation in North Mountain Front of Alvand Mass.

Alvand Mountain is located in the direction of north-west and south east of Hamadan Province in the west of Iran. The morphology of its north front causes instability due to the tectonics and different factors of erosion. Using determination of the rate of erosion or studying elements affecting geomorphic structure, one can assess the rate of slope instability. For assessing cliff morphology retrograde transformation of northern mountain front of Alvand mass, the region has been divided into 12 sub-watersheds, and using different indexes such as decline, retreat, replacement, rounding, sinuous mountain front faceting river gradient indexes, thalweg on deep index, and fans area index transverse topographic symmetry factors, the analysis was carried out. Results define the intensity of morphodynamic activities and erosion in sub-watershed the region and Alvand Northen slope instability. The existence of such slopes not only cause transformation but they also result in decline, retreat, replacement and rounding processes. The retrograde and transformation of mountain front in Alvand, are triangualar and the exit of shutter ridge, facets and sinuous forms of Alvand are sometimes linear and at times curve-linear. This fact expresses retrograde and transformation that was affected by drainage basin spacing, time and wide area. It seems that north mountain front of Alvand mass was under prelacier effective erosion system that causes retrogressive transformation.