Gis based landslide susceptibility assessment of the Kadirli - Aslantaş (Osmaniye) region

In this study, landslide susceptibility assessments were achieved in 523 km2 area around Kadirli town. Inventory map revealed that 3 % of the area affected by landslides which are mostly rotational and complex movements in nature. The average landslide size is 0,07 km2 and the landslides smaller than 0.1 km2 area constitute 80% of all. 30 km.section of the Bakü Tiflis Ceyhan oil pipeline pass through the study area. Some settlements, agricultural lands and some places in vicinity of the pipeline have been adversely affected by landslides. Landslides are mostly located in Kadirli formation of Upper Pliocene which mainly corresponds to hillside morphologic units. Kadirli formation crops out in the 65 % of the entire study area and made up of slightly cemented conglomerate, sandstone and claystone intercalations. The land use map prepared using Landsat TM image revealed that 40 % of the area is represented by bare and farm lands.The GIS based landslide susceptibility map of the study area was prepared using logistic regression analysis. The landslide conditioning factors used in the statistical analysis were geological, landform classification, land use, curvature, aspect, slope, topographic wetness index, stream power index and slope length factor map. 25*25m pixels were used as mapping units during the statistical assessments. The obtained landslide susceptibility map divided into five intervals according to the probability values varying between very low susceptible (p < 0.18) and very high susceptible (p > 0.72) classes. The high and very high susceptible areas corresponds 35.54 % of the entire area where 86.46 % of the landslides were located hereinto. The accomplished landslide susceptibility map with relatively high performance could be used during the medium scale planning strategies.