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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.
31

Geodinamička analiza pomeranja Zemljine kore regionalnog karaktera / A geodynamical analysis of Earth's crust movements of regional character

Sušić Zoran 08 March 2014 (has links)
<p>Stanje Zemljine kore određeno je istovremenim i suprotstavljenim uticajem<br />endodinamičkih i egzodinamičkih procesa. Povr&scaron;inski slojevi omotača<br />Zemljine kore su u stalnom pokretu pod dejstvom uticaja, kao &scaron;to su<br />promena nivoa podzemnih voda, tektonske pojave, klizi&scaron;ta itd. Značajne<br />deformacije mogu se javiti kao posledica niza regionalnih i lokalnih<br />naponskih stanja, posebno u graničnim zonama litosfernih ploča, gde se<br />akumuliraju naponi i javljaju nelinearne innterseizmičke deformacije. U<br />disertaciji je prikazano istraživanje pomeranja Zemljine kore regionalnog<br />karaktera sa geodetskog aspekta, na osnovu ponovljenih opažanja metodom<br />satelitskog pozicioniranja, čime je dat doprinos multidisciplinarnom<br />razumevanju stanja Zemljine kore.</p> / <p>The state of the Earth&rsquo;s crust is determined by the simultaneous and opposed<br />influence of the endodynamic and exodynamic processes. The surface layers of<br />the Earth&rsquo;s crust envelope are in the state of permanent moving due to divers<br />influences, such as the level variation of underground waters, tectonic<br />phenomena, landslides, etc. Significant deformations can arise as a consequence<br />of a number of regional and local strain states, especially in the boundary zones<br />of lithosphere plates where strains are accumulated and non-linear interseismic<br />deformations appear. The subject of the thesis is a study of movements of the<br />Earth&rsquo;s crust of regional character from the aspect of geodesy, on the basis of<br />repeated observations by applying the satellite positioning method. In this way a<br />contribution is given to a multidisciplinary concept of the state of the Earth&rsquo;s crust.</p>
32

Innovation of the Magnetotelluric method and its application to the characterization of the Pyrenean lithosphere

Campanyà i Lloret, Joan 14 February 2013 (has links)
This thesis is a compendium of three papers related to the magnetotelluric (MT) method and its application to the characterization of lithospheric-scale geoelectrical structures. The thesis begins with an Introduction where the motivation and the aims are presented as well as the geological context of the Pyrenees, the previous geophysical studies and the used data set. The Introduction also contains a description of the MT method with basic concepts useful to understand the MT analysis developed in the three papers. Then the three papers, which are the main part of the thesis, are exposed. After the papers, there is a Discussion where the results are commented and compared, extending some of the ideas proposed in the articles and including a new geoelectrical crustal model of the Western Pyrenees. Then there are the Conclusions and proposals of future works related to the MT sites acquired in the Pyrenees and the proposed method for processing MT data. At the end of the thesis there are the references of the cited works and an annex containing a copy of the two published papers and a copy of the submitted manuscript of the third paper. The first published paper determines the geoelectrical structures below the Central Pyrenees using new BBMT and LMT data acquired close to the ECORS-Pyrenees deep seismic profile. The aim of this study has been to improve the results obtained by Ledo (1996) and Pous et al. (1995a), taking advantage of the progress occurred in the last fifteen years associated with the MT method and the acquisition of MT data. The most important improvements that have been achieved are the better definition of the top of the electrical resistivity structure associated with the Iberian subducted lower crust (IBSLC) and the determination of the lithosphere-asthenosphere boundary (LAB) below the Iberian and the European plates close to the collision zone. Complementary, an analysis of the geological properties of the lower-crust and the dehydration point of the muscovite and biotite rocks provides more arguments in favour of the hypothesis of partial melting to explain the geophysical observations associated with the IBSLC. In the second paper the MT method has been applied to characterize the geoelectrical structures below the West-Central Pyrenees in a new MT profile across the Pyrenean mountain range. This new MT profile is 130 km long and is composed by twenty BBMT sites acquired in 2010, seven of them also with LMT data. Results have been compared with the ones obtained in the Central Pyrenees characterizing the main geoelectrical variations between the two MT profiles. An analysis of the thermal re-equilibration of the IBSLC has been developed completing the analysis of the previous paper about the presence or absence of partial melting in the IBSLC. This analysis corroborates partial melting as the best explanation for the low electrical resistivity values of the IBSLC. The LAB below the West-Central Pyrenees has been determined not only below the Iberian and the European plates, as in the Central Pyrenees, but also below the collision zone. Additionally, an unexpected geoelectrical structure completely buried below the Ebro basin has been associated with a Variscan boundary. In the third paper a new method is proposed for processing MT data. The proposed method uses the horizontal magnetic fields recorded at a neighbouring site to process the MT data of a local site from inter-station tensor relationships. Results obtained in the experiments validate the method. A parameter has been defined in order to determine, in each specific study for each used period, if the proposed method can be applied. / Aquesta tesi es composa de tres articles relacionats amb el mètode Magnetotelluric (MT) i la seva aplicació a la caracterització d’estructures geoelèctriques de la litosfera. La tesi comença amb una introducció on es presenten les motivacions d’aquesta i els objectius plantejats, així com el context geològic dels Pirineus, els estudis previs que s’han realitzat i les dades fetes servir pel desenvolupament de la tesis. La introducció conté també una descripció del mètode MT amb l’objectiu d’ajudar a entendre l’anàlisi que es desenvolupa en els articles. Tot seguit s’exposen els tres articles, es discuteixen els resultats obtinguts i s’exposen les conclusions a les que s’ha arribat. El primer article mostra les estructures geoelèctriques sota el Pirineu Central. L’objectiu d’aquest estudi ha estat millorar els resultats de Ledo (1996) i Pous et al. (1995a), aplicant els progressos que hi ha hagut en el camp de la MT en els darrers quinze anys. Els nous resultats han permès caracteritzar millor la zona de fusió parcial associada amb la subducció de l’escorça Ibèrica Inferior (IBSLC) i el límit litosfera astenosfera (LAB). De forma complementaria, s’ha dut a terme un anàlisi de les propietats de l’escorça inferior que ha permès aportar més arguments a favor de la hipòtesis de la fusió parcial. En el segon article el mètode MT s’ha fet servir per caracteritzar les estructures geoelèctriques sota el Pirineu Occidental-Central en un nou perfil de MT. En aquest estudi també s’han observat estructures geoelèctriques associades amb la fusió parcial de la IBSLC i amb el LAB. Sota la conca de l’Ebre s’ha observat per primer cop una anomalia geoelèctrica que s’ha associat amb la presència d’un límit Hercinià. Els resultats han estat comparats amb els del Pirineu Central per tal de caracteritzar l’evolució de les principals estructures geoelèctriques al llarg de la serralada. En el tercer article s’ha proposat un nou mètode per processar dades MT. Aquest mètode utilitza els camps magnètics horitzontals enregistrats en una estació veïna per processar les dades de la zona d’estudi únicament a partir de relacions tensorials entre estacions. Els experiments duts a terme corroboren la validesa del mètode.
33

Žemės plutos horizantaliųjų judesių Ignalinos atominės elektrinės rajone tyrimas geodeziniais metodais / Research of the eartch’s crust horizontal movements in the Ignalina nuclear power plant region by geodetic methods

Stanionis, Arminas 17 January 2006 (has links)
A method prepared and created algorithm for computations and evaluation of relation between Earth’s crust horizontal deformations and variations of tectonic stresses. Hooke’s law was used for relation description. Method of evaluation of Earth’s crust horizontal deformations was improved as well as modelling method based on observation data. Elements of deformation tensors were evaluated by applying finite element method. New data of Earth’s crust horizontal movements and their geodynamic interpretation at the Ignalina Nuclear Power Plant region were obtained.
34

Analýza a inverze povrchových vln - aplikace na Český masiv / Surface Wave Analysis and Inversion-Application to the Bohemian Massif

Kolínský, Petr January 2010 (has links)
title: Surface Wave Analysis and Inversion Application to the Bohemian Massif author: Mgr. Petr Kolínský, DiS. author's e-mail address: kolinsky@irsm.cas.cz departments: Department of Geophysics Faculty of Mathematics and Physics Charles University Prague V Holešovičkách 2, Praha 8 - 180 00, Czech Republic and Department of Seismology Institute of Rock Structure and Mechanics, v.v.i. Academy of Sciences of the Czech Republic V Holešovičkách 41, Praha 8 - 182 09, Czech Republic supervisor: RNDr. Johana Brokešová, CSc. supervisor's e-mail address: johana.brokesova@mff.cuni.cz consultant: RNDr. Jiří Málek, PhD. consultant's e-mail address: malek@irsm.cas.cz keywords: surface waves, group velocity, phase velocity, frequency-time analysis, multiple filtering, tomography, inversion problems, Earth crust structure, Bohemian Massif An overview of surface wave analysis methods as well as of inversion techniques is given. Special attention is paid to the multiple filtering method for dispersion curve estimation, which is described by two different ways in detail. The isometric method is used for dispersion curve inversion and its description and tests are presented. Described methods are further used in applications. The applications show examples of surface wave analysis and inversion for 1D and 2D...

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