High-resolution marine seismic reflection studies on the eastern shelf of the Saros Gulf have revealed the presence of gascharged sediments across a narrow submarine valley incised by the Ganos Fault along the North Anatolian Fault system. Quaternary sediments, accumulated during glacial and interglacial periods through transgressional and progradational units, were controlled by glacio-eustatic sea-level fluctuations and tectonic deformation. The transgressional units made of upward-fining deposits created seals at their tops to form gas accumulation pockets. | Turkish Journal of Earth Sciences Turkish J Earth Sci 2021 30 862-881 http earth TÜBİTAK Research Article doi yer-2107-28 Fault-controlled gas escapes in the shelf sediments of the Saros Gulf NE Aegean Sea 1 2 3 3 Şebnem ÖNDER Naci GÖRÜR Alina POLONIA Luca GASPERINI 1 Department of Geophysical Engineering Faculty of Engineering Çanakkale Onsekiz Mart University Çanakkale Turkey 2 The Science Academy İstanbul Turkey 3 Institute of Marine Sciences National Research Council Bologna Italy Received Accepted Published Online Final Version Abstract High-resolution marine seismic reflection studies on the eastern shelf of the Saros Gulf have revealed the presence of gas- charged sediments across a narrow submarine valley incised by the Ganos Fault along the North Anatolian Fault system. Quaternary sediments accumulated during glacial and interglacial periods through transgressional and progradational units were controlled by glacio-eustatic sea-level fluctuations and tectonic deformation. The transgressional units made of upward-fining deposits created seals at their tops to form gas accumulation pockets. Conversely the progradational units appear heavily eroded at their top which is unfavorable for gas accumulation. The sediment s gas accumulation features include enhanced reflections acoustic blanking or blanket acoustic turbidity acoustic curtain and acoustic columns. In contrast the gas escape features consist of acoustic plumes cloudy turbidity domes and pockmarks. Their concentration along the Ganos Fault indicates that active deformation punctuated by large magnitude earthquakes has played an essential role in their formation storage and seep. Understanding these interactions may provide valuable contributions to hydrocarbon explorations and early-warning strategies against earthquake risk. Key words Aegean Sea North Anatolian Fault Gulf of Saros seismic stratigraphy high-resolution seismic reflection
