# GIS-Based Optimal Route Selection of Submarine Cables Considering Potential Seismic Fault Zones
## 3 Results  
The current version of the developed smart decision-support tool has been efficiently applied in the southeastern Mediterranean Sea. The main aim of the presented implementation is to optimize the routing of three real engineering projects, a submarine telecommunication cable connecting the island of Crete, Greece, with Libya, and two offshore power transmission cables that will be used in the near future to transfer energy to/from the island of Crete to Cyprus and Egypt, respectively.  
Figure 6 provides a further insight of the area under consideration. For the realistic description of the seabed, a digital bathymetry model (DBM) has been created in the GIS  
Figure 5: Submarine power cable and its equivalent cross-section.  
environment based on a GeoTIFF format file that was downloaded from OpenTopography.org [61]. The boundaries of the wider area of interest have been downloaded as a shapefile from Marineregions.org [62] and they have been further processed in GIS. The points represent the origin and destination points (i.e., their approximate locations at the coastline) of the examined case studies.  
Figure 7a-d depict all of the geodata that have been collected and further processed within the GIS environment. The data provided from the Shuttle Radar Topography Mission plus (SRTM plus) of a 30-arc second resolution global bathymetry grid have been utilized to represent the bathymetry of the area under consideration [63]. It is noted that for reasons of simplification, the bathymetric data herein (i.e., Figure 7a) are presented in the form of nested polygons for each depth (i.e., \(-200\) m, \(-1000\) m, \(-2000\) m, \(-3000\) m and \(-4000\) m). The map in Figure 7b illustrates the seabed slope inclination, as derived from the GIS software. Seabed slope inclination varies from \(0^{\circ}\) to slightly more than \(50^{\circ}\). Figure 7c depicts that numerous earthquake events of magnitude M \(\geq\) 4.5 occurred between 1960 and 2022, especially near the island of Crete, according to the United States Geological Survey (USGS) [64].  
According to Figure 7d, there are six main fault zones, four of them are located between the island of Crete and Libya: (i) the Cretan-Rhodes Ridge, (ii) the Hellenic trench, (iii) the East Mediterranean ridge and (iv) the Herodotus trough, whereas the remaining are observed near Cyprus: (v) the West Cyprus arc and (vi) the South Cyprus Trench. The aforementioned seismic fault zones have been acquired in the form of linear entities from a geospatial database infrastructure provided by the International Hydrographic Organization's Data Center for Digital Bathymetry (IHO DCDB) co-located with NOAA's National Centers for Environmental Information (NCEI) and maintained for the General Bathymetric Chart of the Oceans (GEBCO), under the auspices of the IHO and the UNESCO Intergovernmental Oceanographic Commission (IOC) [65] and the global database maintained by the Global Earthquake Model Foundation [66]. It is important to mention that the exact details regarding the geometry, the type and the potential maximum slip of the seismic fault zones are not available. In addition, Figure 8 presents a map showing the thickness of the sediments in the Mediterranean Sea, which was developed by [PERSON] and [PERSON] [67] and is available at the International Hydrographic Organization Data Center for Digital Bathymetry (IHO-DCDB) in the framework of Seabed 2030 Project.  
Figure 6: General view of the area under consideration.  
Figure 8: The thickness of the sediments on the seabed of the Mediterranean Sea (adopted from ([[https://www.ngdc.noaa.gov/mgg/ibcm/ibcmsedt.html](https://www.ngdc.noaa.gov/mgg/ibcm/ibcmsedt.html)]([https://www.ngdc.noaa.gov/mgg/ibcm/ibcmsedt.html](https://www.ngdc.noaa.gov/mgg/ibcm/ibcmsedt.html)) (accessed on 1 February 2023)) [67]).  
Figure 7: Geodata of the area under consideration for the application of the smart decision-support tool: (**a**) bathymetry, (**b**) seabed inclination, (**c**) seismicity and (**d**) major seismically active fault zones.