Landslide risk assessment using a multi-method approach in Hashtchin region (NW of Iran)

Abstract

Landslide risk assessment methods can be carried out at the regional or site scales. In the present study, logistic regression method (a quantitative method) and the fuzzy sets theory (a semi-quantitative method) have been used for landslide hazard and risk assessment, respectively, at a regional scale. The hazard potential and resource damage potential have been obtained from the hazard zonation and the land cover / land use maps. The landslides occurrence probability has been estimated based on the causal factors responsible for slope destabilization, in a specified period of time. At this stage, 75 % of the pixels with landslide have been entered to the model as the estimation group, in which new landslides have occurred with a moderate to high intensity or at least have displaced once or more in the past 50 years. The accuracy of the results from the statistical estimation of landslide occurrence probability have been evaluated and validated based on 25 % of the remaining landslide pixels. Landslide hazard assessment representing the accuracy of prediction model is 83.2 %. The risk zonation was performed by combination of the hazard potential and resource damage potential and using the fuzzy algebraic product operator in the region. Results show that 62.9 % of the area is placed in low and very low risk categories and 19.5 % of the rangeland areas are located in class of high risk zone. Proposed method was used for landslide risk assessment in Hashtchin region (in the northwest of Iran), and obtained results can be used in the land use planning, developmental activities and implementation of building.