Abstract:

In this study, it was aimed to determine landslide susceptibility in the Melet River Basin, where landslides cause significant economic losses and the effects of which continue to be seen currently. A landslide is the most serious natural disaster in the basin located within the borders of Ordu province due to geomorphological-geological and climatic features. In this study, frequency ratio and Landslide Susceptibility Analysis (LSA) methods were used from among bivariate statistical analysis methods. The bivariate analysis method reveals the effect of different variables on landslide formation. Geology and topography maps and satellite images constitute the basic data in this study. The lithology layer was obtained from the geology maps covering the basin, while Digital Elevation Model (DEM) was used to obtain slope, aspect, elevation steps, plan curvature and topographic wetness index (TWI) layers. Rivers were digitized from the topography maps and the distance to river layer of was obtained. Normalized Difference Vegetation Index (NDVI) layer was formed using the Landsat 8 satellite image and distance to road layer was formed via Open Street Map data. The landslide inventory layer pertaining to the study area was obtained using the Directorate of Mineral Research and Exploration (MTA) Samsun plate and land surveys. The inventory map was overlapped with the layers and subsections of the layer with landslide and without landslide were identified. In accordance with the method, the layer weights were determined and registered on the attributes table of the reclassified layers. Susceptibility map was created by adding the layers with determined weights. The proportion of the areas with high and very high landslide susceptibility in the map obtained via frequency ratio method in Melet River Basin account for 12%, the proportion of the moderate susceptibility area account for 27% and the proportion of the low and very low susceptibility areas account for 61%. According to LSA, high and very high susceptibility areas account for 11%, moderate susceptibility areas account for 26%, very low and low susceptibility areas account for 63%. Ulubey and Kabadüz districts are classified as high and very high susceptibility areas within the basin boundaries. Considering the climate characteristics of the study area, landslides are inevitable due to hydro-meteorological events and anthropogenic effects. For this reason, planning should be made by taking into account the susceptibility map.

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