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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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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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Tary, Jean-baptiste; Géli, Louis; Lomax, Anthony; Batsi, Evangelia; Riboulot, Vincent; Henry, Pierre. |
The Sea of Marmara (SoM) is a marine portion of the North Anatolian Fault (NAF) and a portion of this fault that did not break during its 20th century earthquake sequence. The NAF in the SoM is characterized by both significant seismic activity and widespread fluid manifestations. These fluids have both shallow and deep origins in different parts of the SoM and are often associated with the trace of the NAF which seems to act as a conduit. On July 25th, 2011, a 5 strike-slip earthquake occurred at a depth of about 11.5 km, triggering clusters of seismicity mostly located at depths shallower than 5 km, from less than a few minutes up to more than 6 days after the mainshock. To investigate the triggering of these clusters we first employ a match filter... |
Tipo: Text |
Palavras-chave: Shallow seismicity; Triggering; Stress transfer; North Anatolian Fault; Sea of Marmara. |
Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00484/59522/62605.pdf |
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Batsi, Evangelia. |
Since the devastating earthquakes of 1999, east of Istanbul, the submerged section of the North Anatolian Fault (NAF), in the Sea of Marmara (SoM) has been intensively monitored, mainly using land stations. Still, the micro-seismicity remains poorly understood. In addition, although the connection of the SoM with the hydrocarbon gas system from the Thrace Basin is now well established, along with the presence of widespread gas within the sedimentary layers, the role of gas on seismicity is still not recognized.Here, we have analyzed Ocean Bottom Seismometer (OBS) data from two deployments (April-July 2011 and September-November 2014) in the western SoM. Based on a high-resolution, 3D-velocity model, and on non-linear methods (NonLinLoc), our location... |
Tipo: Text |
Palavras-chave: Localisation; Micro-séismicité; Sismomètres de fond de mer; Sismicité induite par le gaz; Micro-seismicity; Earthquake location; Ocean bottom seismometers; Gas-related seismicity. |
Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00497/60906/64254.pdf |
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Batsi, Evangelia; Tsang‐hin‐sun, Eve; Klingelhoefer, Frauke; Bayrakci, Gaye; Chang, Emmy T.y.; Lin, Jing‐yi; Dellong, David; Monteil, Clément; Géli, Louis. |
Ocean bottom seismometers (OBS) commonly record short duration events (SDEs), that could be described by all of these characteristics: (i) duration < 1 s, (ii) one single‐wave train with no identified P‐ nor S‐wave arrivals and (iii) a dominant frequency usually between 4 Hz and 30 Hz. In many areas, SDEs have been associated with gas or fluid‐related processes near cold seeps or hydrothermal vents, although fish bumps, instrumental or current‐generated noise have been proposed as possible sources. In order to address some remaining issues, this study presents results from in situ and laboratory experiments combined with observations from 2 contrasting areas, the Sea of Marmara (Turkey) and the Chilean subduction zone. The in situ experiment was... |
Tipo: Text |
Palavras-chave: Marine seismology; Gas and fluid migration; Sea of Marmara; Chilean subduction. |
Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00507/61895/65983.pdf |
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