## 5 Local Scale Analysis
### Vulnerability Analysis  
The first step of the local scale analysis consists of estimating the vulnerability of the buildings, based on data collected during a field survey. Four different areas were selected for an in-depth risk analysis (Figure 11), each chosen for its unique characteristics to cover a broad range of cases across the valley:  
1. Alpenzu Walser village (Area 01): an Alpine pasture at the edge of the forest;
2. The locality of Noversch (Area 02): a historic settlement on the valley floor;
3. Gressoney-La-Trinite (Area 03): the town centre, with receptive activities and a ski area;
4. Locality Orsa (Area 04): dispersed houses on the slopes at the end of the valley.  
For each location, an estimation of the vulnerability of the buildings was made consisting of five parameters: age and state of conservation, road access and reachability, exposed slope facade and protections, number of floors and building size and use, functions and the presence of people, as summarized in Table 3. Each parameter was assigned a score ranging from 1 (low vulnerability) to 3 (high vulnerability) for each building. The final sum of these scores gives the Total Vulnerability. The highest value found was 15 (historic houses, hardly accessible, unprotected, and still inhabited), while the lowest value was 7 (new houses, located along the main infrastructure, with little exposed facades). The nine scores obtained were then grouped into three categories:  
* V scores 7, 8, and 9 > moderate V;
* V scores 10, 11, and 12 > medium V;
* V scores 13, 14, and 15 > high V.  
The second step involves determining the worth exposed, which takes into account the presence of people in the buildings considered. This factor, called \"temporal spatial probability\", refers to the likelihood that people will be in the area affected by the hazard at the time of its occurrence. The strong seasonal nature of these tourist areas must be considered, as the timing of the potential event is crucial in this context. For the preliminary assessment, the highest value was assigned to public facilities, shops, restaurants, hotels, and mountain huts, as these typically host the largest number of people. A medium value was assigned to houses permanently or occasionally inhabited, while the lowest value was given to uninhabited structures like barns, sheds, garages, etc.  
Figure 10: The Lys Valley: the risk map and its representation as a box-plot for the municipalities.  
Figure 11: Positions of the four case studies for the local scale analysis representing the landscapes of the Lys Valley. Data obtained from regional geoportals and databases of the Autonomous Region of Valle d’Aosta.  
\begin{table}
\begin{tabular}{c c c c} \hline
**Vulnerability** & \multicolumn{3}{c}{**Scores**} \\
**Criteria** & **1 (Moderate)** & **2 (Medium)** & **3 (High)** \\ \hline Age and state of & & & \\ conservation & recent construction & built in the 20 th century & historic house or \\  & & & \\ \hline Road access and & & & \\ reachability & located along the main road & accessible by car & only accessible on foot \\ \hline Exposed slope & & & \\ facade and & small facade with few & & \\ protections & openings & facade with various windows & large, unprotected facade, \\ \hline Number of floors & & & \\ and building size & one floor & two floors & three or more floors \\ \hline Use, functions, and & & & \\ presence of people & & & \\ \end{tabular}
\end{table}
Table 3: Vulnerability criteria and scores used in the local-scale vulnerability analysis.  
Subsequently, with the obtained data, it was possible to calculate the potential damage to buildings by multiplying the vulnerability (V) and worth exposed (W) values. Finally, through combining the potential damage with the hazard values, the total landslide risk assessment was derived.