Landslide Susceptibility Assessment of Gözne Region (mersin Turkey)

Gozne region is located 30 km north of Mersin, on the southern flanks of the Bolkar Mountain Range. Due to the rainfall induced landslide events in 1968 and 2001, 196 residences were either collapsed or heavily damaged in the region. In order to identify the spatial distribution of landslides, detail aerial photo interpretation and field verifications were conducted. Total landslide affected area was identified as 27.7 km2 which refers 7 % of the entire study area. Landslides are characterized mostly by rotational and complex type of movements. The most susceptible units are Mersin ophiolite and Ophiolitic melange units that cover almost 50 % of the area preserving 72% of the all landslides. Landslide susceptibility assessments were performed using logistic regression analyses to identify other potential landslide prone areas in the region. 47 independent geoenvironmental variables were considered such as DEM derivative terrain classifications, geological and morphological units. Landslide inventory datasets were randomly divided into two groups as 80 % for the training and 20 % for the test datasets. Same procedure was repeated five times and logistic regression method was applied for each dataset. Considering the training and test data sets, 78-81% and 65-80% of the landslides were found in high to very high susceptible zones, respectively. Additional validation approaches were also evaluated in order to determine the prediction capacity of the susceptibility maps using ROC curves, Cohen’s Kappa index and prediction and success curves. According to ROC curves, AUC scores obtained between 0.76-0.79 and Cohen’s Kappa index range between 0.431-0.480 which refer acceptable discrimination and moderate classes, respectively. These results suggest that the adequacy of the method and of the maps obtained is reasonably acceptable