A Geospatial Framework for Landslide Risk Assessment of Road Infrastructure at a Regional Level in Greece

This study presents a comprehensive geospatial framework for landslide risk assessment across the 4,523 km road network of the Region of Epirus in Greece. Utilizing a field-verified inventory of 295 active landslides, the research evaluates five key predisposing factors—lithology, slope inclination, elevation, land use, and cumulative annual precipitation—using the bivariate Frequency Ratio (FR) statistical model. Among six tested scenarios, the most robust model integrated all factors, achieving high predictive accuracy by classifying nearly 80% of the study area within Moderate to Very High susceptibility zones. The resulting Landslide Susceptibility Index (LSI) was converted into a Landslide Hazard Index (LHI) and integrated with a weighted Road Vulnerability Map, which categorized road sectors based on functional importance and traffic volume. The final Landslide Risk Map indicates that the most critical risk zones are clustered along major transportation corridors that traverse geologically weak formations, moderate to high precipitation areas and steep mountainous sectors. This quantitative approach provides a vital decision-support tool for regional authorities, enabling the prioritization of geotechnical monitoring and the strategic allocation of resources for infrastructure stabilization. The methodology offers a replicable workflow for enhancing the resilience of transportation networks in landslide-prone Mediterranean regions facing evolving climatic threats.