Evaluation of Effective Factors in Landslide Occurrence Using Logistic Regression Method ACase Study: Syahdareh Hamadan Watershd)

This study aims to prepare a landslide hazard map for the Syahdareh watershed using multivariate logistic regression analysis. To do this the most important factors affecting the occurrence of landslides، including altitude، slope، aspect، annual precipitation، distance from the fault، distance from the drainage system، distance from the road network، land use and litology information were collected and analyzed in the GIS environment. Then، using the interpretation of aerial photos and field surveys in 75 landslide points were identified. 75 points at which there were no landslides were randomly selected from the study area. The landslide factors layers were overlaid on the landslide and non-landslide points to which a code of one and zero was given respectively. Having entered independents variables including all coded classes and dependent variables including 150 landslide and non-landslide points into the SPSS software (version12) the forward stepwise in logistic regression statistical analysis was used for data analysis. The results show that the most effective factors for landslide occurrence include slope، elevation، rainfall، distance from the drainage system and distance from fault. The accuracy of statistical models was confirmed using -2LL، Cox and Snell R2 and Nagelkerk R2.