High-Resolution Seismic Characterization of Shallow Gas Accumulations in the Southern Shelf of Marmara Sea, Turkey

Vardar D., Alpar B.

ACTA GEOPHYSICA, vol.64, no.3, pp.589-609, 2016 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 64 Issue: 3
  • Publication Date: 2016
  • Doi Number: 10.1515/acgeo-2015-0059
  • Journal Name: ACTA GEOPHYSICA
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.589-609
  • Keywords: shallow gas, pockmarks, high-resolution seismic, southern Marmara Sea, acoustic properties, NORTH ANATOLIAN FAULT, SURFACE SEDIMENTS, MIDDLE STRAND, CHARGED SEDIMENTS, CONTINENTAL-SHELF, ACOUSTIC EVIDENCE, AEGEAN SEA, GEMLIK BAY, NW SPAIN, METHANE
  • Istanbul University Affiliated: Yes


High-resolution seismic survey was conducted to investigate acoustic characteristics of gassy sediments along the southern shelf of the Sea of Marmara. The acoustic turbidity zones outlined within the study area are generally below 2-9 m (2-10 ms TWT) the seafloor whilst this vertical distance varies between 9 and 21 m (10-25 ms TWT) for acoustic blanket type reflections. The gassy sediments cover an area of sea floor of about 45, 110, and 75 km(2) in front of Gonen River, Kocasu River, and Gemlik Bay, respectively. The gassy sediments in the center of Gemlik Bay exhibited an elliptical geometry similar to its basin while the others have deltaic forms in front of the rivers. The sea bottom and near surface sedimentary units are made-up of organic-rich sediments, mostly transported by the southern rivers. The gas observed in sediments is thought to be of biogenic origin, which may be caused by degradation of organic matter in the sediment.