## 4 Hazards Analysis
### Landslide Hazard Assessment
Lefkas has mostly shallow soils, with deeper layers found in the north. * Slope Curvature: Soils found on concave slopes are generally more prone to landslides because these landforms tend to accumulate and retain rainfall, increasing soil saturation and instability. In contrast, convex slopes are less likely to retain water and may also indicate the presence of underlying bedrock, which contributes to slope stability. On Lefkas Island, areas with high landslide risk due to slope curvature are limited and scattered across the island. * Slope Aspect: Slopes that receive more sunlight tend to retain less soil moisture, which generally reduces the likelihood of landslides. In Greece, east- to southeast-facing slopes are typically warmer and more sun exposed, resulting in drier conditions that are less favorable for slope failures [34]. Lefkas Island is characterized mainly by north- to northwest-facing slopes, receiving less sunlight and retain more moisture, making them more susceptible to landslides. Although seismic activity is a known landslide trigger--particularly in tectonically active regions like Lefkas ([35; 36])--this factor was excluded due to the lack of spatially detailed seismic acceleration data at a resolution appropriate for island-scale modeling. While this omission reflects a data limitation, it is acknowledged as a key constraint of the current model. Based on the AHP results, the Landslide Hazard Map (Figure 10) shows that most of Lefkas Island falls under medium- to high-hazard categories. Medium-hazard areas are spread across the island, while high- and very-high-hazard zones are concentrated in the central part, and along the eastern and western coastal slopes. Notably, most historical landslides align with these zones (Figure 11), supporting the accuracy of the model. This assessment highlighted areas where slope failures are more likely and points to the need for preventive measures, such as slope stabilization, drainage improvements, and land-use restrictions in high-risk zones. Future versions of this model should incorporate dynamic triggers, including seismic parameters and rainfall thresholds, to enhance realism and predictive capability. \begin{table}
\begin{tabular}{c c c c c c c c c c c c} \hline \hline  & **A** & **B** & **C** & **D** & **E** & **F** & **G** & **H** & **I** & **K** & **Weights** \\ \hline
**A** & 1 & 2 & 3 & 4 & 4 & 5 & 5 & 6 & 6 & 7 & 0.25449 \\ \hline
**B** & 0.5 & 1 & 2 & 4 & 4 & 5 & 4 & 6 & 5 & 7 & 0.19809 \\ \hline
**C** & 0.333 & 0.5 & 1 & 3 & 4 & 5 & 4 & 5 & 4 & 7 & 0.15603 \\ \hline
**D** & 0.25 & 0.25 & 0.333 & 1 & 4 & 4 & 3 & 4 & 3 & 7 & 0.11037 \\ \hline
**E** & 0.25 & 0.25 & 0.25 & 0.25 & 1 & 4 & 3 & 4 & 4 & 6 & 0.08869 \\ \hline
**F** & 0.2 & 0.2 & 0.2 & 0.333 & 0.25 & 1 & 2 & 3 & 3 & 5 & 0.05761 \\ \hline
**G** & 0.2 & 0.25 & 0.25 & 0.333 & 0.333 & 0.5 & 1 & 2 & 3 & 5 & 0.05027 \\ \hline
**H** & 0.167 & 0.167 & 0.2 & 0.25 & 0.25 & 0.333 & 0.5 & 1 & 2 & 5 & 0.03666 \\ \hline
**I** & 0.1667 & 0.2 & 0.25 & 0.333 & 0.25 & 0.333 & 0.333 & 0.5 & 1 & 4 & 0.03126 \\ \hline
**K** & 0.143 & 0.143 & 0.143 & 0.143 & 0.167 & 0.2 & 0.2 & 0.333 & 0.25 & 1 & 0.01652 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Pairwise comparison matrix used in the multi-criteria analysis for landslide susceptibility assessment. A: slope, B: lithology, C: land use, D: distance from faults, E: distance from roads, F: distance from drainage network, G: precipitation, H: soil depth, I: curvature, and K: slope aspect. The numerical values in each cell indicate the degree of preference between the corresponding factors. The final column presents the calculated weights for each factor, along with the consistency ratio (CR) of the matrix. Figure 10: Spatial distribution of normalized parameters used (**a–k**). The Landslide Hazard Map of Lefkas Island (**I**) indicates that the island falls under medium- to high-hazard categories. The map also marks the locations of past landslide events.