# Seismic Resilience in Critical Infrastructures: A Power Station Preparedness Case Study
## 4 Case Study
### The Location and Seismic Risks  
The power station is located in the south of the coastal plain in Israel, near Ashkelon city. Consequently, the seismic hazard evaluation considered the existing seismic risk in this area. The seismic hazard was evaluated based on the defined risks presented by [56; 57; 58]. PGA, a parameter representing the value of ground motion at the site, was applied to assess seismic hazards. The Israeli building seismic design code (SI 413) [23], along with [56], provides PGA zone maps for Israel. These maps were developed using the Probabilistic Seismic Hazard Analysis (PSHA) methodology and provide three return periods: 2%, 5%, and 10% over 50 years. Considering the power station's designation as critical infrastructure, a return period of 2% in 50 years was selected. In the south coastal plain region, where the power station is located, the PGA value was determined to be 0.15 g. According to the hazard scale proposed for ground shaking effects by [PERSON] et al. (2018) [58], a predicted PGA between 0.15 g and 0.20 g is categorized as a high hazard level (Table 1). The soil composition in the southern coastal plain area is not prone to local amplification. Furthermore, as detailed by ([PERSON] et al., 2014) [PERSON], [PERSON], et al. (2014) [57], the site is classified as normal ground, indicating it lacks potential for local amplification. Consequently, the selected PGA value for the primary earthquake event is expected to generate a ground motion of 0.2 g at the site. According to the slope stability analysis carried out by [PERSON] et al. (2008) [59], which presents the sensitivity to slope failure in Israel, the southern part of the coastal plain is categorized at the lowest degrees, \"I-II\". This sensitivity level is considered negligible due to the very high critical acceleration (>0.5 g) required for failure. This aligns with the low slope stability risk at the power station site, attributed to the relatively flat topography of the coastal plain. The absence of significant slopes or hillsides near the site reduces the likelihood of earthquake-induced landslides or slope failures. Regarding liquefaction risk, the coastal area is defined as having a high degree of susceptibility to liquefaction (see Table 2). This means that there is a significant risk of soil liquefaction for foundations that are shallower than 20 m in depth. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Level of Hazard** & **Relative Degree of Hazard (HGS)** & **Criteria** \\ \hline Highest & 4 & PGA \(\geq\) 0.2 g \\ High & 3 & 0.2 g \(>\) PGA \(\geq\) 0.15 g \\ Moderate & 2 & 0.15 g \(>\) PGA\(\geq\) 0.1 g \\ Lowest & 1 & PGA \(<\) 0.1 g \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Earthquake Hazard Scale as proposed by [PERSON] et al. (2018). \begin{table}
\begin{tabular}{c c c} \hline \hline
**Level of** & **Relative Degree** & **Criteria** \\ \hline Highest & 4 & \"Unconsolidated soil\" + \"PGA \(\geq\) 0.15 g\" + \"shallow (\(<\)20 m) \\ ground water\"; reclaimed areas; coastal area within this PGA \\ High & 3 & \"Unconsolidated soil\" + \"0.10 g \(\leq\) PGA \(<\) 0.15 g\" + \"shallow (\(<\)20 m) ground water\"; coastal area within this PGA \\ Moderate & 2 & \"Unconsolidated soil\" + \"0.05 g \(\leq\) PGA \(<\) 0.10 g\" + \"shallow (\(<\)20 m) ground water\"; coastal area within this PGA \\  & & coastal area within this PGA \"Unconsolidated soil\" + \"PGA \(<\) 0.05 g\" + “shallow (\(<\)20 m) ground water”; coastal area within this PGA \\ Lowest & 1 & \"PGA \(<\) 0.05 g\" + “shallow (\(<\)20 m) ground water”; coastal area within this PGA \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Liquefaction Hazard Level as proposed by [PERSON] et al. (2018). The tsunami risk assessment along Israel's Mediterranean coast relies on historical data from approximately 22 events that have impacted the eastern Mediterranean shoreline, with about 10 of these affecting Israel directly. The estimated likelihood of a tsunami occurring in Israel is defined by an event with a return period of 200 years.