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| Batsi, Evangelia; Lomax, Anthony; Tary, Jean-baptiste; Klingelhoefer, Frauke; Riboulot, Vincent; Murphy, Shane; Monna, Stephen; Ozel, Nurcan Meral; Kalafat, Dogan; Saritas, Hakan; Cifci, Gunay; Cagatay, Namik; Gasperini, Luca; Geli, Louis. |
| A detailed study, based on ocean‐bottom seismometers (OBSs) recordings from two recording periods (3.5 months in 2011 and 2 months in 2014) and on a high‐resolution, 3D velocity model, is presented here, which provides an alternative view of the microseismicity along the submerged section of the North Anatolian fault (NAF) within the western Sea of Marmara (SoM). The nonlinear probabilistic software packages of NonLinLoc and NLDiffLoc were used for locating earthquakes. Only earthquakes that comply with the following location criteria (e.g., representing 20% of the total amount of events) were considered for analysis: (1) number of stations≥5; (2) number of phases≥6, including both P and S; (3) root mean square (rms) location error≤0.5 s; and... |
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| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00453/56416/58103.pdf |
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| Grall, Celine; Henry, Pierre; Dupre, Stephanie; Geli, Louis; Scalabrin, Carla; Zitter, Tiphaine A. C.; Sengor, A. M. Celal; Cagatay, M. Namik; Cifci, Gunay. |
| Gases of various sources were collected at the seafloor of the Marmara basin suggesting that the gases expelled have experienced multiple sequences of upward migration, from multiple sources. The pathways of upward migration of gas can be reconstructed by considering the distribution of gas seeps with respect to the near-surface geomorphostructure and the regional stratigraphic architecture of the Marmara Basin. Gas seeps appear to be more favourably localized within a 1–2 km swath around active faults where sediment permeability is probably enhanced by deformation. In the fault zones, fault intersections between sets of transtensive and transpressive subsidiary faults, or between subsidiary faults and main faults, are the preferred gas pathways. These... |
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| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00445/55629/57264.pdf |
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| Okay, Seda; Jupinet, Benoit; Lericolais, Gilles; Cifci, Gunay; Morigi, Catherina. |
| In 2002, the Bosphorus outlet was mapped using an EM 300 multibeam echo-sounder together with a Chirp sonar system. This survey, carried out on board the Ifremer RV 'Le Suroit' in the frame of the BlaSON project, completes the data previously acquired directly at the mouth of the Bosphorus by Di Iorio et al. (1999) in the frame of a NATO SACLANT Undersea Research project using jointly the NATO RV Alliance, and the Turkish Navy Survey ship 'Cubuklu'. This acoustic imaging has identified a canyon system at the slope and a shallow marine fan, which contains shelf incisions extending the Istanbul Strait incision. Multibeam bathymetry, ultra-high resolution seismic profiling and coring correlations on this subaqueous fan area allowed reconstruction of... |
| Tipo: Text |
Palavras-chave: Multibeam; High resolution seismic; Sea level change; High energy Mediterranean water input; Subaqueous fan. |
| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00036/14676/13677.pdf |
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| Hillman, Jess I. T.; Klaucke, Ingo; Bialas, Joerg; Feldman, Howard; Drexler, Tina; Awwiller, David; Atgin, Orhan; Cifci, Gunay; Badhani, Shray. |
| A large geophysical dataset, including bathymetry, and 2D and 3D P-cable seismic data, revealed evidence of numerous gas flares near the S2 Canyon in the Danube Fan, northwestern Black Sea. This dataset allows us to investigate potential relationships between gas migration pathways, gas vents observed at the seafloor and submarine slope failures. Vertical gas migration structures as revealed in the seismics appear to be concentrated near submarine slope failure structures. Where these seismically defined features extend upwards to the seafloor, they correlate with the location of gas flares. However, not all these structures reach the seafloor, in some cases because they are capped by overlying sediments. A strong correlation is inferred between gas... |
| Tipo: Text |
Palavras-chave: Gas migration; Chimneys; Gas hydrate; Danube Fan; Slope failure; Black Sea. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00439/55013/57803.pdf |
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| Saritas, Hakan; Cifci, Gunay; Geli, Louis; Thomas, Yannick; Marsset, Bruno; Henry, Pierre; Grall, Celine; Rochat, Alexis. |
| Based on 3D and 2D high-resolution multichannel seismic reflection data in the Western High-Sea of Marmara, this study reviews shallow gas occurrence and related structures and classifies gas conduit systems within the upper, few hundred meter-thick sediment layers below the seafloor. Acoustic anomalies including high amplitude-reverse polarity reflections (bright spots), low amplitude transparent zones, chaotic or discontinuous reflections, pull-down effects, and plumes in the water column are interpreted in terms of natural gas occurrence and fluid flow structures (e.g., mud volcanoes, pockmarks). The gas occurrence is thought to be mostly of thermogenic origin. Mud volcanoes are one of the primary gas conduits forming craters on the seabed due to... |
| Tipo: Text |
Palavras-chave: Shallow gas; Gas conduit systems; Mud volcano; Pockmark; 2D-3D seismic; Western High; Sea of Marmara. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00456/56737/58689.pdf |
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| Lericolais, Gilles; Algan, Oya; Morigi, Caterina; Okay, Seda; Kirci-elmas, Elmas; Cifci, Gunay. |
| Since the preliminary mapping of the northern Bosphorus outlet of the Black Sea continental shelf by the 90’s NATO project, an important data set bringing morphological, seismic and sedimentological information is now available to describe there a shallow fan system consisting of a main channel and short distributary branches, levees, and sediment waves, correlative to a southern source flowing to the north. This paper brings complementary quantitative data from landscape at the eastern and western shelf area of the shallow fan system. It confirms that the Bosphorus outlet fan preserved on the shelf surface provides an important record of surface water flow. To deduce the history of the Marmara/Black Sea last connexion, it is fundamental to understand how... |
| Tipo: Text |
Palavras-chave: Bosphorus; Black Sea; Seismic; Sediment cores; Multibeam bathymetry; Shallow fan. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00501/61254/64838.pdf |
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