# GIS-Based Optimal Route Selection of Submarine Cables Considering Potential Seismic Fault Zones
## 3 Results
### Case Study 1: Submarine Telecommunication Cable Connecting Crete with Libya  
In the sequence, the smart tool has been applied to investigate several alternative routings in the case of a telecommunication cable, based on an existing routing of a cable connecting Crete with Libya. Seabed inclination, bathymetry and the seismically active fault zones have been taken into account as basic criteria for this case study. It should be noted that the presence of \"no-go\" areas has been neglected due to a lack of relevant data. The developed decision-support tool has been applied by examining the following five scenarios:  
* Scenario 1  
Seabed inclination is extremely more important than bathymetry and seismic fault zones, whereas bathymetry and seismic fault zones have the same importance. * Scenario 2  
Bathymetry is extremely more important than seabed inclination and seismic fault zones, whereas seabed inclination and seismic fault zones have the same importance. * Scenario 3  
Seismic fault zones are extremely more important than seabed inclination and bathymetry, whereas seabed inclination and bathymetry zones have the same importance. * Scenario 4  
An intermediate scenario where seabed inclination, bathymetry and seismic fault zones are equally important. * Scenario 5  
A realistic scenario where the qualitative prioritization of the criteria is based on the experience of cable routing engineers obtained from several industry partners. The utilized scale factors, which are summarized in Table 2, are in accordance with the study of [PERSON] et al. [2]. Table 3 presents the weight values that resulted from the AHP for each of the aforementioned scenarios, as well as the rating score for each sub-criterion. It is noted that similarly to seabed inclination, bathymetry has been distinguished into five sub-criteria. Having assigned the weights and the rating score to the selected criteria, the LCPA technique has been applied within the GIS environment and five different cost (and length) minimized cable routes have been derived (i.e., five different scenarios). Figure 10a,b present the results of the routing analysis. In particular, Route I corresponds to the realistic scenario 5, Route II represents the extreme scenario 1, Route III denotes the extreme scenario with a greater weight value to seismic fault zones, Route IV constitutes the intermediate scenario, whereas Route V corresponds to the extreme scenario 2. In addition, the existing submarine telecommunication cable has been added for comparison. The previously described numerical methodology has been applied to numerically simulate the problem of fault-cable intersection. A single armored (SA) submarine telecommunication cable of typically infinite length has been considered. An equivalent simplified cross-section has been developed, as shown in Figure 11. The outer diameter, \(\mathrm{D_{ext}}\) has been set equal to 28 mm, whereas the inner diameter, \(\mathrm{D_{int}}\) is equal to 1.9 mm. The equivalent elastic modulus has been set equal to 63.06 GPa according to [PERSON] et al. [32]. \begin{table}
\begin{tabular}{c c c c} \hline \hline  & **Seabed Inclination** & **Bathymetry** & **Seismic Fault Zones** \\ \hline
**Seabed Inclination** & 1 & 4 & 1/2 \\ Bathymetry & 1/4 & 1 & 1/9 \\ Seismic Fault Zones & 2 & 9 & 1 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Qualitative prioritization for Case Study 1 with a consistency ratio equal to 0.0013. Figure 11: SA submarine cable and its equivalent cross-section.