Gas and seismicity within the Istanbul seismic gap

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 range, from where pressurized gas is expected to migrate along the MMF, up to the surface sediment layers. Hence, gas-related processes should also be considered for a complete interpretation of the micro-seismicity (~M < 3) within the Istanbul offshore domain

Strategic analysis of healthcare service quality using fuzzy AHP methodology

Managers in the service sector are under pressure to demonstrate that their services are customer-focused and that continuous performance improvement is being delivered. It is essential that customer expectations are properly understood and measured under the constraints that organizations must manage. The majority of the work to date has attempted to use the SERVQUAL (service quality) methodology in an effort to measure service quality. In this study, firstly the concept and factors of service quality are examined. Then a fuzzy AHP (analytic hierarchy process) is structured to evaluate the proposed service quality framework. A case study in healthcare sector in Turkey is presented to clarify the methodology. © 2011 Published by Elsevier Ltd

Clinical importance of serum neopterin level in patients with pulmonary tuberculosis

Objective: Neopterin is a sensitive marker for cell-mediated immune response. Because of this, the neopterin levels of body fluids show cell-mediated immune response in different infectious diseases which involve T cells and macrophages.The aim of this study was to determine the clinical importance of neopterin levels in patients with tuberculosis and compare with those levels of healthy subjects. Methods: Seventy patients with tuberculosis (46 newly diagnosed cases, 15 relapse cases, and 9 multidrug-resistant tuberculosis cases) and 18 healthy adult individuals were included in the study. Neopterin concentrations were measured by the ELISA method according to the protocol of the manufacturer. Chi-square test was used in statistical analysis; p?. 0.05 was considered statistically significant. Results: Serum mean neopterin levels were 23.74. ±. 21.8. nmol/L (median: 18.3) in newly diagnosed patients with pulmonary tuberculosis; 28.69. ±. 21.2. nmol/L (median: 21.2) in relapse patients and 31.28. ±. 14. nmol/L (median: 25.4) in multidrug-resistant tuberculosis cases, respectively. Serum mean neopterin levels were 4.03. ±. 5.12. nmol/L (median: 5.1) in healthy subjects. The serum neopterin levels were found to be significantly higher in patients with tuberculosis than the control group.There was a statistically significant correlation between neopterin positivity (neopterin level ?10. nmol/L was accepted to be positive) and clinical symptoms of hemoptysis and weight loss. Besides statistically significant correlations between neopterin positivity and hemoglobin level, sedimentation rate, mean leukocyte count and radiological involvement (localized or diffuse) were determined. Conclusion: Serum neopterin levels can be used as a helper laboratory finding for the diagnosis of patients with tuberculosis. For this aim, further controlled studies are needed. © 2014 Asian-African Society for Mycobacteriology

Contribution of high-resolution 3D seismic near-seafloor imaging to reservoir-scale studies: application to the active North Anatolian Fault, Sea of Marmara

International audienceHigh Resolution (HR) marine seismic acquisition contributes to numerous research fields. The vertical resolution is of metric scale in order to study geological processes at a short time scale or to characterise small objects. 3D seismic imaging allows optimal resolution to be reached whereas 2D images are blurred mainly by side effects. Developed for the oil industry decades ago and tailored to the exploration for hydrocarbon reservoirs, 3D seismic, as applied to higher resolution targets, is more recent. Available technological advances in acquisition have allowed research institutes to develop innovative 3D high-resolution marine seismic systems tailored to these targets. The seismic survey carried out in 2009 on the Western High, Sea of Marmara, illustrates the value of HR3D imaging. Since the destructive İzmit earthquake in 1999, an intensive international research effort has demonstrated that the Western High is one of the key structures for assessing the processes of deformation related to the North Anatolian Fault (NAF). The 30-km² HR3D survey centred on the main NAF was acquired using a dual streamers-dual source-array configuration. In spite of the minimal 3D processing sequence that was applied to the data, the fine imaging of the seabed and of the sedimentary stratigraphy and structures is much better than HR2D seismic. Comparison with an autonomous underwater vehicle (AUV) multi-beam bathymetric survey carried out at the same location enables the limits of the vertical resolution of the seismic data to be assessed. The lateral resolution is between 13.5 and 25 metres at the seabed. The HR3D seismic data highlight the interplay between tectonic processes and stratigraphy. In particular, differential uplift leads to syntectonic deposition and submarine slides. The widespread occurrence of gas in the sedimentary sequence is clearly shown by anomalously high seismic amplitudes. 3D imaging of these high amplitudes enables the identification of the pathways through faults and permeable units that gas takes as it migrates to the seabed

Control of active faults and sea level changes on the distribution of shallow gas accumulations and gas-related seismic structures along the central branch of the North Anatolian Fault, southern Marmara shelf, Turkey

Detailed reviews of multichannel seismic reflection, sparker, chirp and multibeam data that were collected on the southern Marmara Sea shelf revealed various shallow gas indicators and related sedimentary structures, including enhanced reflections, seismic chimneys, acoustic blanking, bright spots, pockmarks, mound-like features and seeps. Seismic attribute analyses were applied to characterise the existence of gas-bearing sediments. The distribution of shallow gas indicators provides important insights into their origin and the geological factors that control them. Prominent gas accumulations and seeps are observed along the profiles that cross the branches of the central segment of the North Anatolian Fault Zone, which indicates that the gas seeps are controlled by active faulting. This indicates that the faults act as conduits through the sedimentary column. The dense occurrences of gas directly off the river mouths along the shallow bays provide clues about the organic-rich carbon content of the sediments and biogenic methane generation. In some areas, the gas-related acoustic anomalies are mostly located in the upper sediments below the marine unit, which indicates that the gas emissions in these areas were terminated as a result of the increased overburden pressure after the Holocene sea level rise and the deposition of the marine unit

Gas and seismicity within the Istanbul seismic gap

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 range, from where pressurized gas is expected to migrate along the MMF, up to the surface sediment layers. Hence, gas-related processes should also be considered for a complete interpretation of the micro-seismicity (~M &lt; 3) within the Istanbul offshore domain