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| Geli, Louis; Henry, P.; Grall, Celine; Tary, Jean-baptiste; Lomax, A.; Batsi, Evangelia; Riboulot, Vincent; Cros, Estelle; Gurbuz, C.; Isik, S. E.; Sengor, A. M. C.; Le Pichon, X.; Ruffine, Livio; Dupre, Stephanie; Thomas, Yannick; Kalafat, D.; Bayrakci, G.; Coutellier, Q.; Regnier, Thibaut; Westbrook, Graham; Saritas, H.; Cifci, G.; Cagatay, M. N.; Ozeren, M. S.; Gorur, N.; Tryon, M.; Bohnhoff, M.; Gasperini, L.; Klingelhoefer, Frauke; Scalabrin, Carla; Augustin, Jean-marie; Embriaco, D.; Marinaro, G.; Frugoni, F.; Monna, S.; Etiope, G.; Favali, P.; Becel, A.. |
| Understanding micro-seismicity is a critical question for earthquake hazard assessment. Since the devastating earthquakes of Izmit and Duzce in 1999, the seismicity along the submerged section of North Anatolian Fault within the Sea of Marmara (comprising the “Istanbul seismic gap”) has been extensively studied in order to infer its mechanical behaviour (creeping vs locked). So far, the seismicity has been interpreted only in terms of being tectonic-driven, although the Main Marmara Fault (MMF) is known to strike across multiple hydrocarbon gas sources. Here, we show that a large number of the aftershocks that followed the M 5.1 earthquake of July, 25th 2011 in the western Sea of Marmara, occurred within a zone of gas overpressuring in the 1.5–5 km depth... |
| Tipo: Text |
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| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00439/55072/56500.pdf |
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| Henry, P.; Grall, Celine; Kende, J.; Viseur, S.; Ozeren, M. S.; Sengor, A. M. C.; Dupre, Stephanie; Scalabrin, Carla; Geli, Louis. |
| The Sea of Marmara is traversed by the North Anatolian Fault system and also presents abundant emission sites of methane gas into the water column. In order to assess the spatial relationship between gas emissions and active faults, the distribution of distances between gas emission sites and the nearest fault is calculated and compared with the distribution of distances between a uniform random distribution of points (Poisson process representing the null hypothesis of an absence of relationship between gas emissions and faults) and the nearest fault. Interestingly, the distance distribution for the Poisson process is nearly exponential, indicating that the fault map does not have a characteristic scale other than that representing the intensity of the... |
| Tipo: Text |
Palavras-chave: Cold seeps; Gas emissions; Transform plate boundary; Strike-slip fault; Damage zone. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00441/55252/56739.pdf |
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| Sakic, P.; Piete, Helene; Ballu, V.; Royer, J. -y.; Kopp, H.; Lange, D.; Petersen, F.; Ozeren, M. S.; Ergintav, S.; Geli, Louis; Henry, P.; Deschamps, Anne. |
| The submarine Istanbul-Silivri fault segment, within 15 km of Istanbul, is the only portion of the North Anatolian Fault that has not ruptured in the last 250 years. We report first results of a seafloor acoustic ranging experiment to quantify current horizontal deformation along this segment and assess whether the segment is creeping aseismically or accumulating stress to be released in a future event. Ten transponders were installed to monitor length variations along 15 baselines. A joint least squares inversion for across-fault baseline changes, accounting for sound speed drift at each transponder, precludes fault displacement rates larger than a few millimeters per year during the 6 month observation period. Forward modeling shows that the data better... |
| Tipo: Text |
Palavras-chave: Seafloor geodesy; North Anatolian Fault; Marmara Sea; Acoustic ranging. |
| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00344/45513/45067.pdf |
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| Burnard, P.; Bourlange, S.; Henry, Pierre; Geli, Louis; Tryon, M. D.; Natal'In, B.; Sengor, A. M. C.; Ozeren, M. S.; Cagatay, M. N.. |
| Fluids venting from the submarine portion of the Marmara Main Fault (part of the North Anatolian Fault system, Turkey) were sampled in Ti bottles deployed by submersible. The fluids consist of mixtures of fault derived gases, fault related cold seep fluids, and ambient seawater; these components can readily be distinguished using the isotopes of He and the He/Ne ratios. He-3/He-4 ratios range between 0.03 +/- 0.1 and 4.9 +/- 0.4 Ra, indicating that both crustal and mantle derived sources of helium are sampled by the fault. The dominant gas in all the samples analyzed is methane with the abundance of CO2 below detection (<= 2%) in the mantle rich (high He-3/He-4) fluids. This is in contrast to nearly all mantle derived fluids where the C species are... |
| Tipo: Text |
Palavras-chave: Fluids; Gas emission; Helium; Marmara Sea; North Anatolian Fault. |
| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00098/20954/18576.pdf |
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| Kende, Julia; Henry, P.; Bayrakci, G.; Ozeren, M. S.; Grall, C. |
| The free-air gravity in the Marmara Sea reveals that the low density of sedimentary basins is partly compensated in the lower crust. We compiled geophysical upper crust studies to determine the sediment basin geometries in and around the Marmara Sea and corrected the gravity signal from this upper crust geology with the Parker method. Then, assuming long wavelength anomalies in the residual gravity signal is caused by variations in the Moho topography, we inverted the residual to build the Moho topography. The result shows that the Moho is uplifted on an area greater than the Marmara Sea with a maximum crust thinning beneath the basins where the Moho is at about 25 km, 5 km above the reference depth. We then evaluated the Neogene extension by comparing the... |
| Tipo: Text |
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| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00371/48188/48303.pdf |
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