Selecting the Most Appropriate Route for Tehran-Shomal Freeway (Northern Iran) Based on Landslide Susceptibility Mapping

Abstract

The second lot of Tehran-Shomal freeway with approximately length of 22 km is on the development phase to select the suitable rout in central part of Alborz Mountain, northern Iran. There are three main proposed routs for construction of this freeway. According to the geological condition of the area, landslide hazard assessment is one of the main effective factors in rout selecting. So, in this paper we want to prepare an applicable landslide susceptibility map for the study area. For this purpose, at first, nine factors of slope angle, aspect, altitude, lithology, roads proximity, fault proximity, vegetation cover, precipitation and drainage density were recognized as major factors in occurrence of landslide in the study area. Then, the analytical hierarchy process (AHP), the frequency ratio (FR) and weight of evidence (WOE) methods were applied for landslide susceptibility mapping. A landslide inventory map applied to operation of two FR and WOE methods as well as validation of created landslide susceptibility maps. Finally, three landslide susceptibility maps were created using three mentioned method in the GIS environment. These maps were evaluated and validated using the landslide index (Li) and success rate carve (SRC). Results show that the two methods of FR and WOE, with the same SRC value of 80%, present a slightly better model fitting compared to the AHP method with the success rate of 77.2%.