Active Faults Affecting Linear Engineering Projects: Examples From Greece

Siting linear engineering projects on or near active faults is usually inevitable in areas of intense seismotectonic activity, such as Greece. To confidently site and mitigate fault rupturing associated hazards, the design and construction of these projects requires knowledge of exact location of active fault traces as well as determination of their characteristics. Detailed investigations of the geological structures were performed along the 500 km-long Athens-Thessaloniki route in mainland Greece, particularly of the potential for surface faulting across or in the vicinity of the most important transportation facilities and lifelines (highway, railway and natural gas pipeline). The identified faults were evaluated and classified as seismic, active and potentially active, on the basis of geologic and geomorphologic evidences of repeated displacements throughout the Quaternary, as well as on the basis of macroseismic data. The map of active faults was compiled, while the magnitude of possible surface displacements along these faults in case of seismic reactivation was estimated. The dominant faults in the study zone are exclusively of normal or oblique-slip character, striking E–W and acting under N–S oriented extensional stresses. It is estimated that many of the numerous active faults which are crossing the Athens-Thessaloniki route and the other linear lifelines are capable of causing a seismic surface displacement up to about 1 m.