Landslide susceptibility assessment of the Asi watershed, southern Türkiye

Abstract

Landslides constitute recurrent natural hazards worldwide with greater socioeconomic impacts in low-income places. Landslide susceptibility studies are carried out to determine the potential for landslides to occur in a region, to predict possible risks in the future and to integrate this information into sustainable planning and management strategies. Slip-type landslides occur in limited areas of less than 1% of the Asi watershed in Southern Turkey. Therefore, meaningful estimations cannot be made with classical statistical models. Hence, a landslide susceptibility assessment was modeled with the maximum entropy method (MaxEnt), which is a method used for estimation based on a limited number of observations. In the maximum entropy method, the relationship between the areas where landslides are observed, and environmental variables are modeled with the optimum probability density. The analyzes were repeated with three different random selection methods using two thirds of the landslide dataset to analyse it and one third as validation data. The accuracy and precision of the obtained models were evaluated with the area under the receiver operating characteristic curves and success prediction curves. Hence, we performed a susceptibility assessment based on a maximum entropy method in the 7893 km2 Asi watershed. Accordingly, the area under the receiver operating characteristic curves was 0.76, and 72% of the landslides were found in high and very high susceptible areas with a total area of 28%. The determination of the landslides that will develop in the region over time and the susceptibility assessments to be repeated will contribute to the more effective planning of mitigation studies. This method can be applied in other watersheds with localized landslides processes that affect human activities. Landslide susceptibility studies are a fundamental tool for understanding landslide risks at a regional scale and predicting future hazards. These studies have a central role in regional planning, infrastructure management, crisis response and the formulation of sustainable development strategies.