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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Relations entre fluides et sismicité dans le domaine sous-marin à partir de sismographes de fond de mer : étude de cas en Mer de Marmara et Application au Delta du Niger

Tary, Jean-Baptiste 15 March 2011 (has links) (PDF)
Le présent travail de thèse aborde la question du couplage entre fluides et déformation en milieu sous-marin, un sujet d'importance dans le domaine des risques, naturels (séismes, glissements de terrain) ou industriels (stabilité des plateformes de forage en mer, par exemple). Trois études de cas sont présentées : les deux premières concernent la Mer de Marmara, en Turquie, une zone fortement exposée au risque sismique, du fait de la proximité de la Faille Nord-Anatolienne ; la troisième concerne une zone pétrolifère offshore, sur la pente continentale du delta profond du Niger. La première étude de cas en Mer de Marmara porte sur l'activité micro-sismique qui caractérise l'escarpement ouest du Bassin de Tekirdag. Notre étude montre que la déformation contribue à maintenir des perméabilités élevées associées au réseau de failles sous l'escarpement, ce qui permet aux fluides de remonter des réservoirs gaziers du Bassin de Thrace jusqu'à la surface. La deuxième étude de cas porte sur des micro-évènements enregistrés par les sismographes de fond de mer, non sismiques, de courtes durées (200 à 600 msec), et caractérisés par des fréquences comprises entre 10 et 30 Hz. Notre étude montre que ces micro-évènements sont liés à des expulsions de gaz. Les OBS fournissent donc des informations inattendues pour l'étude des processus de dégazage naturel en fond de mer. La troisième étude de cas, sur la pente continentale du Nigeria, démontre que la combinaison de piézomètres et d'OBS voisins en fond de mer permet de suivre l'évolution des phases d'accumulation et de vidange de gaz dans les sédiments superficiels. La détection et la surveillance des phénomènes de dégazage naturel en fond de mer est d'une importance qui pourrait s'avérer critique dans les zones d'exploitation pétrolière en domaine offshore. D'une manière générale, ce travail plaide pour la nécessité : i) de disposer de plusieurs réseaux d'observatoires sous-marins câblés en Mer de Marmara et d'un modèle de vitesse-3D rendant compte du fort gradient de vitesses sismiques dans les couches superficielles (la structure de vitesses du domaine sous-marin étant radicalement différente de celle du domaine émergé, la combinaison des données sismologiques à terre et en mer s'avère très difficile); ii) de développer des approches de surveillance multi-paramètres. Pour chaque paramètre, il est nécessaire de connaître la variabilité naturelle "normale", de manière à détecter les variations anormales. La recherche sur les processus physiques et le développement algorithmique doivent être conduits de front.
12

The Effects Of The Material Density And Dimensions Of The Landslide On The Generated Tsunamis

Insel, Isil 01 September 2009 (has links) (PDF)
In this thesis study / mechanism and modeling of tsunamis generated by landslides are investigated. Landslide parameters affecting the surface wave characterisics are studied. In order to understand occurance of this kind of tsunamis, among many historical tsunamis, the ones that are triggered by landslides are detected and studied. The generation of the landslide generated tsunamis are modeled using TWO-LAYER model, which solves nonlinear long wave equations simultaneously within two interfacing layers with necessary boundary conditions at the sea bed, interface and water surface. The model is applied to one of the possible landslides at offshore Yalova in the Sea of Marmara. Two of the controlling parameters, which are the density and the thickness of the slid material, are analysed and a sensitivity analysis is performed to determine the level of their effects on the evolution and amplitude of the tsunami source. Furthermore, the propagation and coastal amplification of the landslide generated waves are investigated using the tsunami simulation and visualization code NAMI DANCE. The results are presented, compared and discussed.
13

Development Of A Web Gis-based Tsunami Inundation Mapping Service / A Case Study For Marmara Sea Region

Ayca, Aykut 01 June 2012 (has links) (PDF)
Tsunamis, as the catastrophic disasters, can cause loss of live and property when they come to the shores. Preparation of emergency plans is essential to reduce the damage. Consequently, any initiative in tsunami modeling and inundation mapping is of vital importance for progressing safety surveillance and maintenance. In an effort to achieve a thorough analysis of effect of tsunami, it is critical to estimate the geographical extent of possibly affected area and to predict tsunami impacts. The inundation mapping system also must serve to manage the simulation data in a scalable environment to reach end-users in the time of event. For this purpose, in this study, the generation of a Web based Geographic Information System (GIS) to serve inundation maps through web. The research methodology consists of four main stages: (i) simulating tsunamis based on six different scenarios (ii) processing simulation data through a GIS application / (iii) development of web interfaces and implementation of the developed model for Web-GIS application / (iv) verification of the created model for Marmara Sea Region. The proposed system is expected to be an efficient tool for improving inundation mapping efforts for expected tsunamis in Turkey.
14

&#039 / production Of Space! In The Post Earthquake Region: Three Cases Form Duzce

Demirel, Sinem 01 January 2006 (has links) (PDF)
This thesis is about the processes and attitudes behind building production as it is about architecture as such, and it aims at understanding architecture&amp / #8217 / s critical capacity and its relation to wider society. In this context, the differing attitudes and orientations in the construction of the residential environments in D&uuml / zce after the two unsettling earthquakes that took place in 1999 are believed to provide a study field, where the relationship between architecture and different economic, political and cultural structures that constitute civil society can be examined. Against this backdrop, our discussion will concentrate on the specific housing concerns and solutions proposed by three different groups, namely: &amp / #8216 / Solidarity Houses Project&amp / #8217 / realized by the villagers of G&ouml / lyaka, settlement proposal for G&ouml / lyaka prepared by the Project Implementation Unit of Prime Ministry and the struggle of the D&uuml / zce Depremzedeler Dernegi for tenants&amp / #8217 / rights. The examination of these case studies will be based on our reading of Henri Lefebvre&amp / #8217 / s &amp / #8216 / Production of Space&amp / #8217 / and particularly his analytical categories: physical, mental and social space. The relation between this theoretical framework and the case studies will be a reciprocal one, in which the analysis on the three examples of house production will both utilize the analytical framework and be an instrument for understanding it. Although considered separately, the concepts we discuss in each chapter are inextricably interwoven. At the end what we aim to outline is a more total picture of the character of the redevelopment processes after the 1999 Marmara earthquakes and represent architectural practice in its complexity.
15

High-resolution lake-based magnetic mapping and modelling of basement structures, with examples from Küçükçekmece Lagoon, Turkey and Charity Shoal, Lake Ontario

Suttak, Philip A. 10 1900 (has links)
<p>Magnetic surveys are one of the principal geophysical methods employed to map the structure of basement rocks deeply buried below cover strata. In resource studies, aeromagnetic surveys are commonly acquired at regional scales (100-1000’s km2) while very few studies have attempted to resolve basement structures at site-scale (<10 >km2). In this study, high-resolution lake-based magnetic survey methods were evaluated for mapping of deeply-buried basement faults (Küçükçekmece Lagoon, Turkey; 6 km2) and a suspected meteorite impact crater (Charity Shoal, Lake Ontario; 9 km2). Total magnetic intensity (TMI) surveys were acquired using a single Overhauser magnetometer with 50-150 m line spacing. Interpretation of the magnetic data was aided by forward modelling of TMI data and depth to basement estimates using Euler and analytic signal methods. Total magnetic intensity (TMI) maps of Küçükçekmece Lagoon identify several north-northwest trending (340-350°) magnetic lineaments that are aligned with strike-slip faults mapped from offshore seismic data. The pattern of magnetic anomalies in the lagoon is consistent with extensional normal faulting of bedrock and lake sediments. Magnetic results from Charity Shoal reveal a large (>1400 nT) parabolic-shaped magnetic anomaly centered over the crater basin and an annular magnetic high (40-50 nT) corresponding with the basin rim. Modelling results exclude the origin of the CSS as a shallow glacial erosional or karst sinkhole feature and are most consistent with a pre-Paleozoic meteorite impact in the Precambrian basement.</p> / Master of Science (MSc)
16

The evolution and transmission of HA-MRSA ST239 through hospitals in Turkey and intercontinental spread

Aldeljawi, Mona January 2015 (has links)
Next-generation sequencing technology provides high-resolution data for epidemiological surveillance of bacterial pathogens on local and global scales. This approach has been used for many species including Methicillin Resistant Staphylococcus aureus (MRSA). In this thesis I demonstrate the utility of these data for understanding the spread of the globally disseminated clone MRSA ST239. I focus both on local and national-level epidemiology through sequence data of 71 isolates recovered from four hospitals representing three cities in Turkey; Istanbul (x2). Ankara and Izmir. I analyse whole genome sequence data from a further 33 ST239 isolates from global sources. These data were combined with previously published data for phylogenetic analysis based only on the core genome. I demonstrate how transmission events can be inferred from this approach on multiple levels; within hospital, between hospitals and between countries. The data pointed to a European origin of ST239, and independent introductions from Europe to Turkey, South America and East Asia. I also demonstrate how whole genome sequence data can be used to develop bespoke PCR assays, based on phage variation, for rapid local epidemiology. Finally, I consider how the sequence data might be used to explain variation in virulence potential, and describe the distribution and transfer of an important phage-borne virulence determinant, sasX, within Europe. Finally, I identified a single isolate with very strong biofilm forming ability likely due to the over-expression of the important adhesion SasG.
17

Preparation Of A Source Model For The Eastern Marmara Region Along The North Anatolian Fault Segments And Probabilistic Seismic Hazard Assessment Of Duzce Province

Cambazoglu, Selim 01 March 2012 (has links) (PDF)
The North Anatolian Fault System is one of the most important active strike-slip fault systems in the world. The August 17, 1999 and November 12, 1999 earthquakes at Kocaeli and D&uuml / zce are the most recent devastating earthquakes. The study area lies in the Eastern Marmara Region and is bounded by the 28.55-33.75 E and 40.00-41.20 N, latitude and longitude coordinates, respectively. There are numerous studies conducted in the study area in terms of active tectonics and seismicity, however studies are scale dependent. Therefore, a comprehensive literature survey regarding active tectonics of the region was conducted and these previous studies were combined with the lineaments extracted from 10 ASTER images via principle component analysis manual extraction method. Therefore, a line seismic source model for the Eastern Marmara region was compiled mainly based on major seismic events of instrumental period. The seismicity of these line segments were compared with the instrumental period earthquake catalogue compiled by Kandilli Observatory and Earthquake Research Institute with a homogeneous magnitude scale between 1900 and 2005. Secondary event and completeness of this catalogue was checked. The final catalogue was matched with the compiled seismic source for historical seismicity and source-scenario-segment-weight relationships were developed. This developed seismic source model was tested by a probabilistic seismic hazard assessment for D&uuml / zce city center by utilizing four different ground motion prediction equations. It was observed that Gutenberg-Richter seismicity parameter &lsquo / b&rsquo / does not have significant effect over the model, however change in the segmentation model have a low but certain influence.
18

Neural Network Prediction Of Tsunami Parameters In The Aegean And Marmara Seas

Erdurmaz, Muammer Sercan 01 July 2004 (has links) (PDF)
Tsunamis are characterized as shallow water waves, with long periods and wavelengths. They occur by a sudden water volume displacement. Earthquake is one of the main reasons of a tsunami development. Historical data for an observation period of 3500 years starting from 1500 B.C. indicates that approximately 100 tsunamis occurred in the seas neighboring Turkey. Historical earthquake and tsunami data were collected and used to develop two artificial neural network models to forecast tsunami characteristics for future occurrences and to estimate the tsunami return period. Artificial Neural Network (ANN) is a system simulating the human brain learning and thinking behavior by experiencing measured or observed data. A set of artificial neural network is used to estimate the future earthquakes that may create a tsunami and their magnitudes. A second set is designed for the estimation of tsunami inundation with relation with the tsunami intensity, the earthquake depth and the earthquake magnitude that are predicted by the first set of neural networks. In the case study, Marmara and Aegean regions are taken into consideration for the estimation process. Return periods including the last occurred earthquake in the Turkish seas, which was the izmit (Kocaeli) Earthquake in 1999, were utilized together with the average earthquake depths calculated for Marmara and Aegean regions for the prediction of the earthquake magnitude that may create a tsunami in the stated regions for various return periods of 1-100 years starting from the year of 2004. The obtained earthquake magnitudes were used together with tsunami intensities and earthquake depth to forecast tsunami wave height at the coast. It is concluded that, Neural Networks predictions were a satisfactory first step to implement earthquake parameters such as depth and magnitude, for the average tsunami height on the shore calculations.
19

Sustainable Development Within The Region Strategies and The Complex Social System : What Can Turkey and U.S.A. learn from Skåne, Sweden

Tepecik, Aslı, Anderson, Eric January 2006 (has links)
Thanks primarily to the international community, sustainable development has in recent decades been more in the forefront. Many communities around the world are taking part in discussions and implementing strategies that address sustainable development. However, Sweden has been and continues to be extremely proactive in addressing sustainable development. Perhaps, this can be seen best in the län of Skåne. There are numerous communities throughout Skåne that address sustainable development. In addition, and what also makes Skåne an even more interesting case study is its recent history, which includes a significant influx of immigrants, the construction of the Öresund Bridge, and the desire of the national government of Sweden to address sustainable development. This project looks at a specific region in the two types of countries that do not address sustainable development (Turkey and the U.S.A.) and examines what methods from Skåne can be implemented into the respective regions. In addition, addressing sustainable development in a regional context involves the creation of a complex social system. Therefore, the paper also analyzes how these two regions can think and operate like regions and initiate a plan for sustainable development. / tepecikasli@gmail.com, eem_anderson@yahoo.com
20

Simulating Co2 Sequestration In A Depleted Gas Reservoir

Ozkilic, Ismet Oke 01 September 2005 (has links) (PDF)
Carbon dioxide is one of the greenhouse gases which have strong impacts on the environment and its amount in the atmosphere is far beyond to be ignored. Carbon dioxide levels are projected to be reduced by sequestering it directly to the underground. High amounts of carbon dioxide can be safely stored in underground media for very long time periods. Storage in depleted gas reservoirs provides an option for sequestering carbon dioxide. In 2002, production of Kuzey Marmara gas reservoir has been stopped due to gas storage plans. Carbon dioxide sequestration in Kuzey Marmara field has been considered in this study as an alternative to the gas storage projects. Reservoir porosity and permeability maps were prepared with the help of Surfer software demo version. These maps were merged with the available Kuzey Marmara production information to create an input file for CMG-GEM simulator and a three dimensional model of the reservoir was created. History match of the field model was made according to the 1998-2002 production data to verify the similarity between the model and actual reservoir. Kuzey Marmara field is regarded as a candidate for future gas storage projects. The reservoir still contains producible natural gas. Four different scenarios were prepared by considering this fact with variations in the regional field properties and implemented into previously built simulation model. These scenarios primarily focus on sequestering carbon dioxide while producing as much as natural gas possible. After analyzing the results from the scenarios it is realized that / CO2 injection can be applied to increase natural gas recovery of Kuzey Marmara field but sequestering high rate CO2 emissions is found out to be inappropriate.

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