Optimal Routing of Gas Pipelines in Seismic Regions Using an Efficient Decision-Support Tool: A Case Study in Northern Greece  
[PERSON]  
1 School of Chemical and Environmental Engineering, Technical University of Crete, 73100 Chania, Greece; 1  
[PERSON]  
2 School of Rural, Surveying and Geoinformatics Engineering, National Technical University of Athens, 15772 Athens, Greece; 2  
[PERSON]  
1 School of Chemical and Environmental Engineering, Technical University of Crete, 73100 Chania, Greece; 1  
Footnote 1: email: [EMAIL_ADDRESS]  
Optimal route selection of CI is a complex and demanding task that is typically carried out \"manually\", i.e., it heavily relies on the expertise and subjective opinion of engineers. Initially, a suitable routing corridor is identified based on the available and reliable data of the area under examination using existing analog maps. A preliminary survey is then conducted along this corridor, and several alternative CI routes are examined. After analyzing the survey data and ensuring that any potential hazards or obstacles have been avoided, the optimal route is chosen. Nevertheless, this manual approach can be time-consuming, error-prone, and limited in scope. It does not always guarantee the optimal path, as it does not take into account the various project-specific criteria, constraints, and design guidelines that usually complicate the selection of optimal routing. To address this issue, researchers have developed mathematical models and algorithms to select the optimal route for CI [2; 3]. Although such models are not affected by human bias, they encounter difficulties in handling the vast amount of geodata required for such complex spatial multi-criteria applications, as well as with the efficient visualization of the corresponding results. As a solution, the use of Geographic Information System (GIS) has replaced the aforementioned models. GIS offers a robust method for capturing, managing, evaluating, and visualizing information while enabling the efficient handling of geospatial data for multi-criteria analysis. GIS-based tools allow users to overlay different layers of geospatial data and simulate various scenarios, thereby ensuring that decisions are made with high precision and accuracy. In applications such as the optimal route selection of CI, where, according to [PERSON] [4], approximately 70% of a project's financial administration and resource allocation are based on geospatial information, GIS offers a valuable solution that overcomes the aforementioned limitations of traditional methods and mathematical models. Furthermore, GIS provides the Least-Cost Path Analysis (LCPA) method, which utilizes a series of sophisticated geoprocessing tools to identify the most cost-effective route on a given cost surface between specified starting and ending points [5]. Relevant research has indicated that utilizing GIS for the optimal route selection of CI can lead to cost savings of up to 30% compared to the traditional process of CI routing [6; 7]. Furthermore, the LCPA can be integrated with advanced Multi-Criteria Decision Methods (MCDMs) to improve the process of decision-making. The combination of GIS and MCDMs has been successfully implemented in various fields, including land-use analysis, urban planning and site suitability analysis. In the process of optimum CI routing, GIS and MCDMs have been effectively combined by many researchers (e.g., [5; 7; 9]). Nevertheless, large-scale CI often cross seismic-prone areas for hundreds to thousands of kilometers, thus being considerably vulnerable to various earthquake-related geohazards, such as strong ground motion, slope instabilities, soil liquefaction phenomena, and seismic fault ruptures at the ground surface. Numerous significant failures of CI resulting from earthquake-related geohazards have been reported over the past few decades.