Assessment and treatment of earthquake-related geohazards threatening offshore gas pipelines in the Mediterranean sea
Proceedings Publication Date
The transportation of hydrocarbons to Central and Northern Europe is currently being performed by high-pressure onshore pipelines coming mainly from Central Asia. Undoubtedly, in the following decades the increased demand for energy in European countries will require the smooth and safe transfer of hydrocarbons from East Mediterranean, Middle East, and North Africa. This process is expected to be performed via offshore pipeline networks and seaside facilities connecting various countries in the wider Mediterranean region (i.e., Tunisia, Italy, Greece, Cyprus, Turkey, Lebanon, Israel, etc). However, since the Mediterranean region is characterized by moderate to high seismicity, the seismic design of any offshore pipeline should aim to eliminate the probability of occurrence of potential accidents such as explosion, fire, leakage, etc., and their devastating consequences (deaths/injuries, economic loss, environmental pollution, etc). This goal may be achieved through: (a) the identification and the quantification of the potential geohazards, and (b) the realistic estimation and, if needed, the effective improvement of the integrity of offshore pipelines. The potential earthquake-related geohazards, apart from strong ground motion, include mainly coastal or submarine landslides, active faults, soil liquefaction phenomena, and in some cases tsunamis. Since the accumulated experience worldwide related to the design of offshore pipelines exists mainly in low-seismicity regions (such as North Sea, Gulf of Mexico, etc), the objective of the current work is to shed some light to the very challenging issue of seismic design of offshore gas pipelines. After a short presentation of the geology, the bathymetry and the seismicity that characterizes the Mediterranean region, the main earthquake-related geohazards are briefly described. Finally, the paper conceptually proposes certain technically and economically feasible mitigation/protection measures.