Quantitative landslide risk analysis in the Hashtchin area (NW-Iran)

Abstract

Quantitative risk models were obtained for each element by integrating landslide hazard and vulnerability models in the Hashtchin area (NW-Iran). Landslide hazard has been analysed in two stages. In the first stage, magnitude of landslides has been estimated by their volume and velocities. With the help of causative factors and based on landslide pixels, which have occurred or have been reactivated at least once in the last 50 years, a landslide hazard model was constructed using logistic regression modelling approach. Vulnerability values (0–1) were obtained by comparing damages experienced in the past 50 years by each type of element. Obtained risk values are not precise predictions of future losses but rather a means to identify areas where damages are likely to be greater and require priority for mitigation actions. The final result is a risk map combining all damages per pixel for a 50-year period in Hashtchin area. By studying the landslide hazard and risk zonation maps in this region, the possibility of them happening in the so-called stable slopes in similar regions can be predicted, and the best actions for stabilising the regions and reducing the damages can be determined. The methods proposed allow the identification of the areas where greater damages are to be expected and prevention efforts would have better benefit/cost ratios.

Keywords:

• Landslides
• hazard
• risk
• vulnerability
• damage and hashtchin