GIS-based landslide susceptibility assessment: a case study in Kelemen Valley (Yenice-Karabuk, NW Turkey)

This study focuses on revealing the landslide susceptibility of mainly the Kelemen Valley and adjacent valleys in the Western Black Sea Region of Turkey by investigating the parameters causing landslide occurrences in the region in a GIS environment and applying the frequency rate method on landslide-prone areas. Many buildings and houses in the study area, 382 houses to be exact, had to be evacuated by the General Directorate of Disaster Affairs of Turkey based on the findings from landslide studies conducted in the region since 1950 and were declared unsuitable for construction and residence due to disaster. Therefore, it is of a vital significance to disclose the factors of landslide occurrences in the Kelemen Valley and consequently to prepare landslide susceptibility maps. For this purpose, 82 landslide exposed areas are determined by field surveys and checked against satellite imagery. All 82 landslides are found to have occurred in the Cretaceous Ulus Formation with the same climate and same vegetation, which are not considered distinctive parameters for the region. These findings have given rise to exclude these parameters from analyses on the basis that they are proclaimed as common parameters; instead, the parameters such as slope, aspect and distance to river are taken into consideration and assessed in ArcGIS software. Finally, the landslide susceptibility of the region has been obtained. Furthermore, a comparison is conducted between the existing landslides and the outcome map, and it is deduced that the map produced has a correlation ratio of 86 % with the existing occurrences for high-risk areas. This finding clearly dictates that land-slideprone areas need to be accounted for when planning for new settlement areas.