Landslide susceptibility assessment along the southern coast of the Caspian Sea, Iran

Here, we investigated the landslide susceptibility in the southern coast of the Caspian Sea, located in the northern part of Iran. This is of high importance for this area as it is highly touristic and agriculturally used and therefore of high value for the local inhabitants. Lack of landslide susceptibility map regarding this area is particularly a main motivation for this study. As a basis for modeling, a field mapping of different landslide types was performed. According to the field studies, this area has a high potential for landslide occurrence, and various kinds of mass movement can be observed all over the area. In order to preparing the area’s landslide susceptibility map, topographic, geotechnical, and landslide data were gathered, digitalized, and stored as raster layers. Then, using the infinite slope analysis, the static safety factor was determined in different conditions of saturation (m) and thickness (t) of landslide in order to get the most appropriate landslide susceptibility map. The accuracy of analysis was evaluated by comparing the recent landslides with the FS maps. The results indicated that the map obtained using m = 1 and t = 5 m compared with other maps has more compliance with the area. Therefore, this condition was used as cutoff in preparing the area’s landslide susceptibility map. This map comprises five susceptibility ranges: very low, low, moderate, high, and very high. This map shows that high percent of the region (36 %) is subject to landslides. The landslide susceptibility map was verified using 69 older landslides in the area. The results indicated that most of the landslides in the area were concentrated in high and very high susceptibility classes. The landslide susceptibility map prepared in this study can be practical in engineering projects and architectural activities in the investigated area. Copyright Springer Science+Business Media Dordrecht 2013