Dissertations / Theses on the topic 'Applied geophysics'
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Platt, John Daniel. "Dynamics and Materials Physics of Fault Rupture and Glacial Processes." Thesis, Harvard University, 2015. http://nrs.harvard.edu/urn-3:HUL.InstRepos:14226054.
Full textHarris, Matthew W. "Numerical realization of the generalized Carrier-Greenspan transform for the shallow water wave equations." Thesis, University of Alaska Fairbanks, 2015. http://pqdtopen.proquest.com/#viewpdf?dispub=1598961.
Full textRun-up of long waves in sloping U-shaped bays is studied analytically in the framework of the 1-D nonlinear shallow-water theory. By assuming that the wave flow is uniform along the cross-section, the 2-D nonlinear shallow-water equations are reduced to a linear semi-axis variable-coefficient 1-D wave equation via the generalized Carrier-Greenspan transformation (Rybkin et al., 2014). A spectral solution is developed by solving the linear semiaxis variable-coefficient 1-D equation via separation of variables and then applying the inverse Carrier-Greenspan transform. To compute the run-up of a given long wave a numerical method is developed to find the eigenfunction decomposition required for the spectral solution in the linearized system. The run-up of a long wave in a bathymetry characteristic of a narrow canyon is then examined.
Fortson, Samuel King. "Usability Engineering Applied to an Electromagnetic Modeling Tool." Thesis, Virginia Tech, 2012. http://hdl.handle.net/10919/33665.
Full textMaster of Science
Bergman, Björn. "High-Resolution Seismics Methods Applied to Till Covered Hard Rock Environments." Doctoral thesis, Uppsala University, Department of Earth Sciences, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-4811.
Full textReflection seismic and seismic tomography methods can be used to image the upper kilometer of hard bedrock and the loose unconsolidated sediments covering it. Developments of these two methods and their application, as well as identifying issues concerning their usage, are the main focus of the thesis. Data used for this development were acquired at three different sites in Sweden, in Forsmark 140 km north of Stockholm, in the Oskarshamn area in southern Sweden, and in the northern part of the Siljan Ring impact crater area.
The reflection seismic data were acquired with long source-receiver offsets relative to some of the targeted depths to be imaged. In the initial processing standard steps were applied, but the uppermost part of the sections were not always clear. The longer offsets imply that pre-stack migration is necessary in order to image the uppermost bedrock as clearly as possible. Careful choice of filters and velocity functions improve the pre-stack migrated image, allowing better correlation with near-surface geological information.
The seismic tomography method has been enhanced to calculate, simultaneously with the velocity inversion, optimal corrections to the picked first break travel times in order to compensate for the delays due to the seismic waves passing through the loose sediments covering the bedrock.
The reflection seismic processing used in this thesis has produced high-quality images of the upper kilometers, and in one example from the Forsmark site, the image of the uppermost 250 meters of the bedrock has been improved. The three-dimensional orientation of reflections has been determined at the Oskarshamn site. Correlation with borehole data shows that many of these reflections originate from fracture zones.
The developed seismic tomography method produces high-detail velocity models for the site in the Siljan impact area and for the Forsmark site. In Forsmark, detailed estimates of the bedrock topography were calculated with the use of the developed tomography method.
Thirunavukkarasu, Senganal. "Impedance Matching for Discrete, Periodic Media and Application to Two-Scale Wave Propagation Models." Thesis, North Carolina State University, 2015. http://pqdtopen.proquest.com/#viewpdf?dispub=3690210.
Full textIttharat, Detchai. "3D radio reflection imaging of asteroid interiors." Thesis, Colorado School of Mines, 2014. http://pqdtopen.proquest.com/#viewpdf?dispub=1557520.
Full textImaging the interior structure of comets and asteroids in 3D holds the key for understand- ing early Solar System and planetary processes, aids mitigation of collisional hazards, and enables future space investigation. 3D wavefield extrapolation of time-domain finite differ- ences, which is referred to as reverse-time migration (RTM), is a tool to provide high-quality images of the complex 3D-internal structure of the target. Instead of a type of acquisition that separately deploys one orbiting and one landing satellite, I discuss dual orbiter systems, where transmitter and receiver satellites orbit around the asteroid target at different speeds. The dual orbiter acquisition can provide multi-offset data that improve the image quality by illuminating the target from different directions and by attenuating coherent noise caused by wavefield multi-pathing. Shot-record imaging requires dense and evenly distributed receiver coordinates to fully image the interior structure at every source-location.
I illustrate a 3D imaging method on a complex asteroid model based on the asteroid 433 Eros using realistic data generated from different acquisition designs for the dual orbiter system. In realistic 3D acquisition, the distribution and number of receivers are limited by the acquisition time, revolving speed and direction of both the transmitter and receiver satellites, and the rotation of the asteroid. The migrated image quality depends on different acquisition parameters (i.e., source frequency bandwidth, acquisition time, the spinning rate of the asteroid) and the intrinsic asteroid medium parameters (i.e., the asteroid attenuation factor and an accurate velocity model).
A critical element in reconstructing the interior of an asteroid is to have different ac- quisition designs, where the transmitter and receivers revolve quasi-continuously in different inclinational and latitudinal directions and offer evenly distributed receiver coordinates in the shot-record domain. Among different acquisition designs, the simplest orbit (where the transmitter satellite is fixed in the longitudinal plane and the receiver plane gradually shifts in the latitudinal direction around the asteroid target) offers the best data coverage and requires the least energy to shift the satellite. To obtain reasonable coverage for successfully imaging the asteroid interior, the selected acquisition takes up to eight months. However, this mission is attainable because the propulsion requirements are small due to the slow (< 10 cm/s) orbital velocities around a kilometer-sized asteroid.
Johansson, Stefan. "Earthquake Analysis Using a Migration Based Detection Algorithm Applied to Local Earthquake Data." Thesis, Uppsala universitet, Geofysik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-325373.
Full textI denna studie analyserades jordskalvsdata med hjälp av en nyligen utvecklad 'migration based detection'-algoritm (Wagner et al. 2017). En mjukvarumiljö skräddarsydd för manuell analys av stora kvantiteter av jordskalv detekterade av MBD-algoritmen iordningställdes, varpå MBD-algoritmen sedan applicerades på 13 dagar av seismisk data från ett nätverk av 26 seismiska stationer i det geologiskt sett komplexa Hengill-området i sydvästra Island. Totalt detekterades 859 jordskalv som genomgick manuell analys. Av dessa klassificerades 483 stycken som bekräftade eller troliga jordskalv, vilket resulterar i en uppskattad felmarginal om ca. 44 %. En delmängd om 53 väldefinierade jordskalv valdes ut för noggrannare analys av ursprungsplats och tidpunkt genom manuell plockning av P-fasankomst. Omlokaliseringen resulterade i en genomsnittlig differens om ca. 0.6 km i vardera koordinat i horisontalplanet och ca. 1.4 km i höjdled. Resultat från projektet kan användas som referensdata vid vidareutveckling av MBD-algoritmen samt ger viss insyn i prestandan hos MBD-algoritmen. Den iordningställda datormiljön kan användas som bas för vidare analys av jordskalv detekterade av MBD-algoritmen.
Wheeler, Mark Lee. "A comparative study of art and the convolution method as applied to cross borehole geophysical tomography." Ohio : Ohio University, 1987. http://www.ohiolink.edu/etd/view.cgi?ohiou1183124445.
Full textTrinh, Phuong-Thu. "3D Multi-parameters Full Waveform Inversion for challenging 3D elastic land targets." Thesis, Université Grenoble Alpes (ComUE), 2018. http://www.theses.fr/2018GREAU033/document.
Full textSeismic imaging of onshore targets is very challenging due to the 3D complex near-surface-related effects. In such areas, the seismic wavefield is dominated by elastic and visco-elastic effects such as highly energetic and dispersive surface waves. The interaction of elastic waves with the rough topography and shallow heterogeneities leads to significant converted and scattering energies, implying that both accurate 3D geometry representation and correct physics of the wave propagation are required for a reliable structured imaging. In this manuscript, we present an efficient and flexible full waveform inversion (FWI) strategy for velocity model building in land, specifically in foothill areas.Viscoelastic FWI is a challenging task for current acquisition deployment at the crustal scale. We propose an efficient formulation based on a time-domain spectral element method (SEM) on a flexible Cartesian-based mesh, in which the topography variation is represented by an accurate high-order geometry interpolation. The wave propagation is described by the anisotropic elasticity and isotropic attenuation physics. The numerical implementation of the forward problem includes efficient matrix-vector products for solving second-order elastodynamic equations, even for completely deformed 3D geometries. Complete misfit gradient expressions including attenuation contribution spread into density, elastic parameters and attenuation factors are given in a consistent way. Combined adjoint and forward fields recomputation from final state and previously saved boundary values allows the estimation of gradients with no I/O efforts. Two-levels parallelism is implemented over sources and domain decomposition, which is necessary for 3D realistic configuration. The gradient preconditioning is performed by a so-called Bessel filter using an efficient differential implementation based on the SEM discretization on the forward mesh instead of the costly convolution often-used approach. A non-linear model constraint on the ratio of compressional and shear velocities is introduced into the optimization process at no extra cost.The challenges of the elastic multi-parameter FWI in complex land areas are highlighted through synthetic and real data applications. A 3D synthetic inverse-crime illustration is considered on a subset of the SEAM phase II Foothills model with 4 lines of 20 sources, providing a complete 3D illumination. As the data is dominated by surface waves, it is mainly sensitive to the S-wave velocity. We propose a two-steps data-windowing strategy, focusing on early body waves before considering the entire wavefield, including surface waves. The use of this data hierarchy together with the structurally-based Bessel preconditioning make possible to reconstruct accurately both P- and S-wavespeeds. The designed inversion strategy is combined with a low-to-high frequency hierarchy, successfully applied to the pseudo-2D dip-line survey of the SEAM II Foothill dataset. Under the limited illumination of a 2D acquisition, the model constraint on the ratio of P- and S-wavespeeds plays an important role to mitigate the ill-posedness of the multi-parameter inversion process. By also considering surface waves, we manage to exploit the maximum amount of information in the observed data to get a reliable model parameters estimation, both in the near-surface and in deeper part.The developed FWI frame and workflow are finally applied on a real foothill dataset. The application is challenging due to sparse acquisition design, especially noisy recording and complex underneath structures. Additional prior information such as the logs data is considered to assist the FWI design. The preliminary results, only relying on body waves, are shown to improve the kinematic fit and follow the expected geological interpretation. Model quality control through data-fit analysis and uncertainty studies help to identify artifacts in the inverted models
Costa, Adeilton Fernandes da. "Emprego do método da eletro-resistividade na caracterização da lixeira de Porto Velho - RO assentada em meio fraturado /." Rio Claro : [s.n.], 2008. http://hdl.handle.net/11449/102890.
Full textBanca: Antonio Celso de Oliveira Braga
Banca: Jairo Roberto Jimenéz Rueda
Banca: Vagner Roberto Elis
Banca: Ene Glória da Silveira
Resumo: Ensaios geofísicos de eletro-resistividade, através das técnicas da sondagem elétrica vertical e imageamento elétrico (configurações Schlumberger e dipolo-dipolo), foram executados na área da lixeira da cidade de Porto Velho, Estado de Rondônia, com o objetivo de identificar a contaminação do subsolo e das águas subterrâneas. A geologia sobre a qual está assentado o aterro de Porto Velho é constituída por sedimentos pleistoceno (argilo-arenosos com concreções lateríticas) assentados sobre rochas graníticas da Formação Santo Antônio. Os resultados mostraram que a aplicação dessas duas técnicas permite identificar locais de ocorrências dos resíduos, zonas de fraturas, diferentes litotipos do subsolo, fluxo das águas subsuperficiais e avaliar o impacto ambiental causado no meio ambiente.
Abstract: Resistivity survey, with vertical electrical sounding and electrical imaging (Schlumberger and dipole-dipole configurations), were done at the waste disposal area, in city of Porto Velho, state of Rondônia, Brazil with the objective to identify the contamination of the subsoil and groundwater. The local geology is constituted by pleistocenic sediments (clay-sandy litology with lateritic concretionary) overlies granitic rocks of Santo Antônio Formation. The results showed that integrating this geophysical techniques can identify places of occurrences of waste, fractures zones, different lithotypes the subsoil, underground flow and evaluate the environmental impact caused by the waste disposal
Doutor
Gandolfo, Otavio Coaracy Brasil. "Um estudo do imageamento geoelétrico na investigação rasa." Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/44/44133/tde-25042008-142218/.
Full textThis paper addresses a detailed, in-depth study on data aquisition, processing and interpretation methodologies for 2D electrical profilings, focusing on investigations oriented to shallow targets. Two-dimensional (electrical profilings) acquisition techniques were used on a wide range of arrays - dipole-dipole, pole-dipole, pole-pole and Wenner arrays - for efficiency comparison purposes. A real 3D acquistion was tested with the pole-pole array in order to check its potential use and limitations. Schlumberger was the array used for SEVs, which helped to interpret and quantify 2D geoelectrical sections, especially as to the vertical distribution of resistivity. The 2D geoelectrical models were generated with an inversion computer program (RES2DINV), which basically corrects any distortions found in the apparent resistivity pseudosections corresponding to the arrays included in this study. These models create images that better match the subsurface geological reality, therefore simplifying the interpretation of results. We tried to explore the full potential use of the inversion computer program for good quality images. The geophysical interpretation was always based on the subsurface information available (boreholes, trenches, wells and outcrop). Resolution is critical in a shallow investigation scale. This study tried to show that the use of small spacings between electrodes (less than four meters), particularly in dipole-dipole arrays, allows for more in-depth investigation levels (greater than eight) without compromising signal quality. On the other hand, dipole-dipole and pole-pole arrays allow for a larger number of investigation levels without small spacings limitations, but with a slight loss of definition. Consequently, there is a significant increase in the amount of data generated at the section, enhancing 2D resolution. Another aspect tested and assessed was the use of multiple spacings between electrodes on the same survey profile. In addition to resolution in shallow sections (thanks to small spacings), this interesting procedure allows deeper investigation levels (due to larger spacings) in the same section. The efficacy of this practice was verified both in the development of pseudo-sections and in the geoelectrical models generated by inversion modelling. The methodology was tested in three different areas in order to map a shallow water table, determine the depth and shape of the bedrock, and map a potential contaminant plume. In addition to the broad literature review available, this paper also covered the controversial topic of depth investigation actually present in electrode arrays typically used in electrical resistivity methods. This thesis tried to provide a better understanding of \"geoelectrical resistivity imaging\" and related topics such as: electrode array, procedures required to generate good volumes of data in the section, efficient use of the inversion computer program behind the models and, lastly, interpretation of results, always based on the subsurface information available and on other supporting geophysical methods or techniques.
Costa, Adeilton Fernandes da [UNESP]. "Emprego do método da eletro-resistividade na caracterização da lixeira de Porto Velho - RO assentada em meio fraturado." Universidade Estadual Paulista (UNESP), 2008. http://hdl.handle.net/11449/102890.
Full textCoordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Ensaios geofísicos de eletro-resistividade, através das técnicas da sondagem elétrica vertical e imageamento elétrico (configurações Schlumberger e dipolo-dipolo), foram executados na área da lixeira da cidade de Porto Velho, Estado de Rondônia, com o objetivo de identificar a contaminação do subsolo e das águas subterrâneas. A geologia sobre a qual está assentado o aterro de Porto Velho é constituída por sedimentos pleistoceno (argilo-arenosos com concreções lateríticas) assentados sobre rochas graníticas da Formação Santo Antônio. Os resultados mostraram que a aplicação dessas duas técnicas permite identificar locais de ocorrências dos resíduos, zonas de fraturas, diferentes litotipos do subsolo, fluxo das águas subsuperficiais e avaliar o impacto ambiental causado no meio ambiente.
Resistivity survey, with vertical electrical sounding and electrical imaging (Schlumberger and dipole-dipole configurations), were done at the waste disposal area, in city of Porto Velho, state of Rondônia, Brazil with the objective to identify the contamination of the subsoil and groundwater. The local geology is constituted by pleistocenic sediments (clay-sandy litology with lateritic concretionary) overlies granitic rocks of Santo Antônio Formation. The results showed that integrating this geophysical techniques can identify places of occurrences of waste, fractures zones, different lithotypes the subsoil, underground flow and evaluate the environmental impact caused by the waste disposal
Warneford, Emma S. "The thermal shallow water equations, their quasi-geostrophic limit, and equatorial super-rotation in Jovian atmospheres." Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:6604fcac-afe6-4abe-8a6f-6a09de4f933f.
Full textHabana, Nlingilili Oarabile Kgosietsile. "Gravity Recovery by Kinematic State Vector Perturbation from Satellite-to-Satellite Tracking for GRACE-like Orbits over Long Arcs." The Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu1578042687104082.
Full textVaucher, Julien. "Processus géophysiques de surface des plaines de lave de la province volcanique de Cerberus, Mars." Phd thesis, Université Paul Sabatier - Toulouse III, 2007. http://tel.archives-ouvertes.fr/tel-00181347.
Full textStewart, Andrew L. "The role of the complete Coriolis force in cross-equatorial transport of abyssal ocean currents." Thesis, University of Oxford, 2011. http://ora.ox.ac.uk/objects/uuid:6bf3faff-ec7e-4d11-bdfe-c54ae9d03895.
Full textLuo, Wenyu. "Three-dimensional propagation and scattering around a conical seamount." Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/40296.
Full textThis electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Thesis (Ph. D.)--Joint Program in Applied Ocean Science and Engineering (Massachusetts Institute of Technology, Dept. of Mechanical Engineering; and the Woods Hole Oceanographic Institution), 2007.
In this thesis, a numerically effcient three-dimensional propagation and scattering model is developed based on the three-dimensional coupled mode theory for axisymmetric bathymetry. The three-dimensional coupled mode approach applied in this thesis is fundamentally identical to the one applied in earlier models, such as the one presented by Taroudakis [20]. Thus, it is based on a Fourier expansion of the acoustic field around a seamount, with each azimuthal expansion coefficient being represented by a two-way coupled mode formulation. However, earlier formulations were severely limited in terms of frequency, size and geometry of the seamount, the seabed composition, and the distance between the source and the seamount, and are totally inadequate for modeling high-frequency, large-scale seamount problems. By introducing a number of changes in the numerical formulation and using a standard normal mode model (C-SNAP) for determining the fundamental modal solutions and coupling coefficients, orders of magnitude improvement in efficiency and fidelity has been achieved, allowing for realistic propagation and scattering scenarios to be modeled, including effects of seamount roughness and realistic sedimentary structure.
(cont.) Also, by the simple superposition principle, the computational requirements are made independent of the distance between the seamount and the source and receivers, and dependent only on the geometry of the seamount and the frequency of the source. First, this thesis investigates the scattering from a cylindrical island, which is the simplest case of a conical seamount problem. Our model, using the superposition method, can solve the cylindrical problem in Athanassoulis and Prospathopoulos's paper [3] with the same accuracy while saving about 4/5 computational effort. Second, this thesis demonstrates the spectral coupled mode approach, which includes a two-way coupled mode model and a superposition representation of the field. Third, this thesis applies the three-dimensional model to investigate some physics issues of three-dimensional seamount scattering. As a result of the investigation, we learn that the Nx2D model is a poor approximation of the true three-dimensional model when the three-dimensional effects are significant, though it is a good approximation of the three-dimensional model otherwise. The convergence of the model in terms of the seamount discretization is also discussed and demonstrated.
(cont.) Finally, our three-dimensional spectral coupled mode model is tested by the application of the Kermit Seamount problem with realistic ocean environmental data from the 2004 BASSEX experiment.
by Wenyu Luo.
Ph.D.
Sivelle, Vianney. "Couplage d'approches conceptuelles, systémiques et distribuées pour l'interprétation de traçages artificiels en domaine karstique : implications pour la détermination de la strucure interne des aquifères karstiques." Thesis, Toulouse 3, 2019. http://www.theses.fr/2019TOU30180.
Full textThe main objective of these thesis is to improve the understanding of the internal structure of karstic aquifers by relying on the interpretation of artificial tracer tests. To meet these objectives, this thesis is based on the karst watersheds of Baget and Aliou (Ariège, France) as well as other karst hydrosystems (the Norville, Val de Loire and Foubanne systems) included in the National Karts Observation Service (SNO Karst, INSU-CNRS) and the tracing database of the BRGM including the Ouysse karst system. The overall approach adopted for this thesis is to couple the results of different approaches. [1] Conceptual reservoirs modeling with the dedicated KarstMod model allows the partitioning of flows at the scale of the watershed and to understand the dynamics of the exchanges between the matrix and the conduits, in the short and long term. It is estimated that the annual contribution of the matrix to the total outflow is about 3% and can increase up to 25% during periods of low precipitation. [2] A systemic approach of the "transfer function" type has been developed and applied to various hydrosystems (the Norville, Ouysse, Val de Loire and Foubanne systems). This approach consists of studying the dynamics of solute mass transport by interpreting artificial tracer tests data and partitioning the flows by estimating the residence times of the different components that contribute to solute transfer between the injection and recovery points. [3] A distributed approach integrating a coupling of geophysical data and pseudo-genetic simulations makes it possible to simulate drainage networks. The associated solute flows and mass transport are then simulated and compared with field data. This is an approach to deduce the structuring of underground flows from the data of artificial tracer tests
Touchard, Frédéric. "Caractérisation hydrogéologique d'un aquifère en socle fracturé : Site de Ploemeur (Morbihan)." Phd thesis, Université Rennes 1, 1998. http://tel.archives-ouvertes.fr/tel-00675884.
Full textBecker, Kyle M. "Geoacoustic inversion in laterally varying shallow-water experiments using high-resolution wavenumber estimation." Thesis, Massachusetts Institute of Technology, 2001. http://hdl.handle.net/1721.1/29056.
Full textIncludes bibliographical references (leaves 161-170).
Sound propagation in shallow water is highly dependent on the interaction of the sound field with the bottom. In order to fully understand this problem, it is necessary to obtain reliable estimates of bottom geoacoustic properties that can be used in acoustic propagation codes. In this thesis, perturbative inversion methods and exact inverse methods are discussed as a means for inferring geoacoustic properties of the bottom. For each of these methods, the input data to the inversion is the horizontal wavenumber spectrum of a point-source acoustic field. The main thrust of the thesis work concerns extracting horizontal wavenumber content for fully three-dimensionally varying waveguide environments. In this context, a high-resolution autoregressive (AR) spectral estimator was applied to determine wavenumber content for short aperture data. As part of this work, the AR estimator was examined for its ability to detect discrete wavenumbers in the presence of noise and also to resolve closely spaced wavenumbers for short aperture data. As part of a geoacoustic inversion workshop, the estimator was applied to extract horizontal wavenumber content for synthetic pressure field data with range-varying geoacoustic properties in the sediment. The resulting wavenumber content was used as input data to a perturbative inverse algorithm to determine the sound speed profile in the sediment. It was shown using the high-resolution wavenumber estimator that both the shape and location of the range-variability in the sediment could be determined.
(cont.) The estimator was also applied to determine wavenumbers for synthetic data where the water column sound speed contained temporal variations due to the presence of internal waves. It was shown that reliable estimates of horizontal wavenumbers could be obtained that are consistent with the boundary conditions of the waveguide. The Modal Mapping Experiment (MOMAX), an experimental method for measuring the full spatial variability of a propagating sound field and its corresponding modal content in two-dimensions, is also discussed. The AR estimator is applied to extract modal content from the real data and interpreted with respect to source/receiver motion and geometry. For a moving source, it is shown that the wavenumber content is Doppler shifted. A method is then described that allows the direct measure of modal group velocities from Doppler shifted wavenumber spectra. Finally, numerical studies are presented addressing the practical issues associated with using MOMAX type data in the exact inversion method of Gelfand-Levitan.
by Kyle M. Becker.
Ph.D.
Degenhardt, John Jerome. "A model for the development of a lobate alpine rock glacier in southwest Colorado, USA implications for water on Mars /." Texas A&M University, 2002. http://hdl.handle.net/1969/320.
Full textHincapie, Jaime Omar. "Shallow geophysical techniques applied to archaeology, economic geology, and groundwater resources." To access this resource online via ProQuest Dissertations and Theses @ UTEP, 2008. http://0-proquest.umi.com.lib.utep.edu/login?COPT=REJTPTU0YmImSU5UPTAmVkVSPTI=&clientId=2515.
Full textFlores, Zamora Juan Carlos. "Integration of Geophysical Interpretation Methods Applied in the Perdido Fold Belt." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for petroleumsteknologi og anvendt geofysikk, 2013. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-23129.
Full textRzeznik, Andrew Joseph. "Applied math in geophysical fluids : partially trapped wave problems and mining plumes." Thesis, Massachusetts Institute of Technology, 2018. http://hdl.handle.net/1721.1/120657.
Full textCataloged from PDF version of thesis.
Includes bibliographical references (pages 129-132).
The first portion of this work focuses on leaky modes in the atmospheric sciences. Leaky modes (related to quasi-modes, scattering resonances, and the singularity expansion method) are discrete, oscillatory and decaying modes that arise in conservative systems where waves are partially trapped. By replacing the infinite domain with a finite domain and appropriate boundary conditions it is possible in many cases to construct a complete basis for the solution in terms of these modes. Formulating such effective boundary conditions requires a notion of the direction of propagation of the waves. For this purpose we introduce a generalization of the concept of group speed for exponentially decaying but conservative waves. This is found via an extended modulation argument and a generalization of Whitham's Average Lagrangian theory. The theory also shows that a close relationship exists between the branch cuts of the dispersion relation and the propagation direction, and is used to create spectral decompositions for simple problems in internal gravity waves. The last chapter considers deep-sea nodule mining operations, which potentially involve plans for discharge plumes to be released into the water column by surface operation vessels. We consider the effects of non-uniform, realistic stratifications with vertical shear on forced compressible plumes. The plume model is developed to account for the influence of thermal conduction through the discharge pipe and an initial adjustment phase. We investigate the substantial role of compressibility, for which a dimensionless number is introduced to determine its importance compared to that of the background stratification. Our results show that (i) small-scale stratification features can have a significant impact, (ii) in a static ambient there exists a discharge flow rate that minimizes the plume vertical extent, (iii) the ambient velocity profile plays an important role in determining the final plume scale and dilution factor, and (iv) for a typical plume the dilution factor is expected to be several hundred to a thousand.
by Andrew Joseph Rzeznik.
Ph. D.
Fortin, Jerome. "Compaction homogène et compaction localisée des roches poreuses.Etude expérimentale et théorique." Phd thesis, Université Pierre et Marie Curie - Paris VI, 2005. http://tel.archives-ouvertes.fr/tel-00180388.
Full textlocalisée. Sous certaines pressions moyennes effectives, la déformation inélastique se développe sous forme de bandes de compaction. Pour comprendre la formation des bandes de compaction, nous avons enregistré, puis re-localisé les émissions acoustiques au cours de plusieurs expériences.
Amitrano, David. "Complexité et Dynamique de l'endommagement et de la rupture,Mécanique, sismicité et invariance d'échelle des objets géologiques." Habilitation à diriger des recherches, Institut National Polytechnique de Lorraine - INPL, 2005. http://tel.archives-ouvertes.fr/tel-00173641.
Full textSkrede, Ole-Johan. "Explicit, A Priori Constrained Model Parameterization for Inverse Problems, Applied on Geophysical CSEM Data." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for matematiske fag, 2014. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-27343.
Full textMachado, Cruz Alberto. "Integrated geological and geophysical studies applied to understanding the evolution of the Offshore Amazon Basin." Electronic Thesis or Diss., Sorbonne université, 2018. http://www.theses.fr/2018SORUS466.
Full textThe Offshore Amazon Basin (known in Portuguese as Bacia da Foz do Amazon) is located in the far north of the Brazilian Equatorial Margin. This basin has attracted the attention of the scientific community for several decades due to its large-scale sedimentary processes related to the colossal sediment influx provided by the Amazon River. However, most of the investigations carried on the Offshore Amazon Basin were restricted to the uppermost Quaternary succession of the Amazon Deep-sea Fan and some pioneer works aiming deeper strata lacked a reliable chronostratigraphic control. In order to better understand the temporal and spatial evolution of the post-rift stratigraphic succession of the Offshore Amazon Basin, multidisciplinary studies supported by interpretations of seismic, well log, chronostratigraphic data and geophysical potential field models were carried out during this PhD thesis
Garvey, Ryan J. "A study of unstable rock failures using finite difference and discrete element methods." Thesis, Colorado School of Mines, 2013. http://pqdtopen.proquest.com/#viewpdf?dispub=3557944.
Full textCase histories in mining have long described pillars or faces of rock failing violently with an accompanying rapid ejection of debris and broken material into the working areas of the mine. These unstable failures have resulted in large losses of life and collapses of entire mine panels. Modern mining operations take significant steps to reduce the likelihood of unstable failure, however eliminating their occurrence is difficult in practice. Researchers over several decades have supplemented studies of unstable failures through the application of various numerical methods. The direction of the current research is to extend these methods and to develop improved numerical tools with which to study unstable failures in underground mining layouts.
An extensive study is first conducted on the expression of unstable failure in discrete element and finite difference methods. Simulated uniaxial compressive strength tests are run on brittle rock specimens. Stable or unstable loading conditions are applied onto the brittle specimens by a pair of elastic platens with ranging stiffnesses. Determinations of instability are established through stress and strain histories taken for the specimen and the system.
Additional numerical tools are then developed for the finite difference method to analyze unstable failure in larger mine models. Instability identifiers are established for assessing the locations and relative magnitudes of unstable failure through measures of rapid dynamic motion. An energy balance is developed which calculates the excess energy released as a result of unstable equilibria in rock systems. These tools are validated through uniaxial and triaxial compressive strength tests and are extended to models of coal pillars and a simplified mining layout.
The results of the finite difference simulations reveal that the instability identifiers and excess energy calculations provide a generalized methodology for assessing unstable failures within potentially complex mine models. These combined numerical tools may be applied in future studies to design primary and secondary supports in bump-prone conditions, evaluate retreat mining cut sequences, asses pillar de-stressing techniques, or perform backanalyses on unstable failures in select mining layouts.
Kelbert, Anna. "Geophysical inverse theory applied to reconstruction of large-scale heterogeneities in electrical conductivity of earth's mantle." Thesis, Cardiff University, 2006. http://orca.cf.ac.uk/54090/.
Full textMcElroy, William John. "Development of geophysical mapping and data processing methods applied to base metal ore deposits in Ireland." Thesis, Queen's University Belfast, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.296823.
Full textSarafian, Emily Kathryn. "Geophysical and petrological constraints on ocean plate dynamics." Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/111716.
Full textCataloged from PDF version of thesis.
Includes bibliographical references.
This thesis investigates the formation and subsequent motion of oceanic lithospheric plates through geophysical and petrological methods. Ocean crust and lithosphere forms at mid-ocean ridges as the underlying asthenosphere rises, melts, and flows away from the ridge axis. In Chapters 2 and 3, I present the results from partial melting experiments of mantle peridotite that were conducted in order to examine the mantle melting point, or solidus, beneath a mid-ocean ridge. Chapter 2 determines the peridotite solidus at a single pressure of 1.5 GPa and concludes that the oceanic mantle potential temperature must be -60 °C hotter than current estimates. Chapter 3 goes further to provide a more accurate parameterization of the anhydrous mantle solidus from experiments over a range of pressures. This chapter concludes that the range of potential temperatures of the mantle beneath mid-ocean ridges and plumes is smaller than currently estimated. Once formed, the oceanic plate moves atop the underlying asthenosphere away from the ridge axis. Chapter 4 uses seafloor magnetotelluric data to investigate the mechanism responsible for plate motion at the lithosphere-asthenosphere boundary. The resulting two dimensional conductivity model shows a simple layered structure. By applying petrological constraints, I conclude that the upper asthenosphere does not contain substantial melt, which suggests that either a thermal or hydration mechanism supports plate motion. Oceanic plate motion has dramatically changed the surface of the Earth over time, and evidence for ancient plate motion is obvious from detailed studies of the longer lived continental lithosphere. In Chapter 5, I investigate past plate motion by inverting magnetotelluric data collected over eastern Zambia. The conductivity model probes the Zambian lithosphere and reveals an ancient subduction zone previously suspected from surface studies. This chapter elucidates the complex lithospheric structure of eastern Zambia and the geometry of the tectonic elements in the region, which collided as a result of past oceanic plate motion. Combined, the chapters of this thesis provide critical constraints on ocean plate dynamics.
by Emily Kathryn Sarafian.
Ph. D.
Zarroug, Moundheur. "Asymptotic methods applied to some oceanography-related problems." Doctoral thesis, Stockholm : Department of Meteorology, Stockholm University, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-37763.
Full textAt the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 3: Manuscript. Paper 4: Manuscript.
Angeli, Matthieu. "Etude multiéchelle de la dégradation des roches par la cristallisation de sels dans les réseaux poreux." Phd thesis, Université de Cergy Pontoise, 2007. http://tel.archives-ouvertes.fr/tel-00239456.
Full textWagner, Gregory LeClaire. "On the coupled evolution of oceanic internal waves and quasi-geostrophic flow." Thesis, University of California, San Diego, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10128416.
Full textOceanic motion outside thin boundary layers is primarily a mixture of quasi-geostrophic flow and internal waves with either near-inertial frequencies or the frequency of the semidiurnal lunar tide. This dissertation seeks a deeper understanding of waves and flow through reduced models that isolate their nonlinear and coupled evolution from the Boussinesq equations. Three physical-space models are developed: an equation that describes quasi-geostrophic evolution in an arbitrary and prescribed field of hydrostatic internal waves; a three-component model that couples quasi-geostrophic flow to both near-inertial waves and the near-inertial second harmonic; and a model for the slow evolution of hydrostatic internal tides in quasi-geostrophic flow of near-arbitrary scale. This slow internal tide equation opens the path to a coupled model for the energetic interaction of quasi-geostrophic flow and oceanic internal tides.
Four results emerge. First, the wave-averaged quasi-geostrophic equation reveals that finite-amplitude waves give rise to a mean flow that advects quasi-geostrophic potential vorticity. Second is the definition of a new material invariant: Available Potential Vorticity, or APV. APV isolates the part of Ertel potential vorticity available for balanced-flow evolution in Eulerian frames and proves necessary in the separating waves and quasi-geostrophic flow. The third result, hashed out for near-inertial waves and quasi-geostrophic flow, is that wave-flow interaction leads to energy exchange even under conditions of weak nonlinearity. For storm-forced oceanic near-inertial waves the interaction often energizes waves at the expense of flow. We call this extraction of balanced quasi-geostrophic energy 'stimulated generation' since it requires externally-forced rather than spontaneously-generated waves. The fourth result is that quasi-geostrophic flow can encourage or 'catalyze' a nonlinear interaction between a near-inertial wave field and its second harmonic that transfers energy to the small near-inertial vertical scales of wave breaking and mixing.
Valois, Rémi. "Caractérisation structurale de morphologies karstiques superficielles et suivi temporel de l'infiltration à l'aide des méthodes électriques et sismiques." Phd thesis, Université Pierre et Marie Curie - Paris VI, 2011. http://tel.archives-ouvertes.fr/tel-00659289.
Full textMorin, Eymeric. "Évolution morpho-sédimentaire de la vallée de la Choisille (sud-ouest du Bassin parisien, France) depuis le Weichsélien. Spécificité de l'impact climatique et anthropique en Europe du Nord-Ouest." Phd thesis, Université François Rabelais - Tours, 2011. http://tel.archives-ouvertes.fr/tel-00627074.
Full textSmigelski, Jeffrey Ralph. "Water Level Dynamics of the North American Great Lakes:Nonlinear Scaling and Fractional Bode Analysis of a Self-Affine Time Series." Wright State University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=wright1379087351.
Full textTaboga, Alessia. "The development of integrated high-resolution geophysical, photogrammetric and GPS surveying applied to landslides in the South Wales coalfield." Thesis, Cardiff University, 2011. http://orca.cf.ac.uk/54058/.
Full textGuyoton, Fabrice. "Sismicité et structure lithosphérique des Alpes occidentales." Phd thesis, Grenoble 1, 1991. http://tel.archives-ouvertes.fr/tel-00544553.
Full textGraciolli, Vinicius Medeiros. "A novel classification method applied to well log data calibrated by ontology based core descriptions." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2018. http://hdl.handle.net/10183/174993.
Full textA method for the automatic detection of lithological types and layer contacts was developed through the combined statistical analysis of a suite of conventional wireline logs, calibrated by the systematic description of cores. The intent of this project is to allow the integration of rock data into reservoir models. The cores are described with support of an ontology-based nomenclature system that extensively formalizes a large set of attributes of the rocks, including lithology, texture, primary and diagenetic composition and depositional, diagenetic and deformational structures. The descriptions are stored in a relational database along with the records of conventional wireline logs (gamma ray, resistivity, density, neutrons, sonic) of each analyzed well. This structure allows defining prototypes of combined log values for each lithology recognized, by calculating the mean and the variance-covariance values measured by each log tool for each of the lithologies described in the cores. The statistical algorithm is able to learn with each addition of described and logged core interval, in order to progressively refine the automatic lithological identification. The detection of lithological contacts is performed through the smoothing of each of the logs by the application of two moving means with different window sizes. The results of each pair of smoothed logs are compared, and the places where the lines cross define the locations where there are abrupt shifts in the values of each log, therefore potentially indicating a change of lithology. The results from applying this method to each log are then unified in a single assessment of lithological boundaries The mean and variance-covariance data derived from the core samples is then used to build an n-dimensional gaussian distribution for each of the lithologies recognized. At this point, Bayesian priors are also calculated for each lithology. These distributions are checked against each of the previously detected lithological intervals by means of a probability density function, evaluating how close the interval is to each lithology prototype and allowing the assignment of a lithological type to each interval. The developed method was tested in a set of wells in the Sergipe-Alagoas basin and the prediction accuracy achieved during testing is superior to classic pattern recognition methods such as neural networks and KNN classifiers. The method was then combined with neural networks and KNN classifiers into a multi-agent system. The results show significant potential for effective operational application to the construction of geological models for the exploration and development of areas with large volume of conventional wireline log data and representative cored intervals.
Masuda, Ryuichi. "A comparative study of the algebraic reconstruction technique and the constrained conjugate gradient method as applied to cross borehole geophysical tomography." Ohio : Ohio University, 1989. http://www.ohiolink.edu/etd/view.cgi?ohiou1182444036.
Full textFaroqy, Anna. "Investigating the changes in the geophysical and geotechnical properties of fine-grained soils when exposed to changes in vertically applied loads." Thesis, University of Birmingham, 2018. http://etheses.bham.ac.uk//id/eprint/8811/.
Full textDelacou, Bastien. "Tectonique et géodynamique actuelle de l'arc alpin - Approche sismotectonique et modélisation numérique." Phd thesis, Université de Nice Sophia-Antipolis, 2004. http://tel.archives-ouvertes.fr/tel-00008598.
Full textUn modèle de ré-équilibrage gravitaire est avancé et testé par modélisation numérique en éléments finis, d'une part en 2.5D, d'autre part en 2D (coupe ECORS). Ces études de modélisation montrent l'importance des phénomènes d'étalement gravitaire dans la chaîne, aboutissant à un régime de déformation/contraintes proche de celui observé par les outils sismotectoniques et permet de proposer un régime tectonique actuel post-collisionnel au niveau des Alpes centrales/occidentales.
Des études de quantifications de la déformation montrent des taux de déformation faibles, de l'ordre de 1 à 3 mm/a pour les calculs sur base GPS et de 0.1 à 0.4 mm/a pour les calculs sur une base sismologique (la différence entre les deux quantifications posant la question des déformations asismiques dans la chaîne). Les taux de rotation montrent des rotations faibles, de 2 à 2.5 degrés/Ma, probablement associé à la rotation antihoraire de la plaque Apulienne qui entraînerait la rotation antihoraire du coeur de l'arc, tandis que des rotations horaires observées en domaine externe résulteraient de la rotation de blocs situés le long des grands décrochements dextres de la bordure occidentale de l'orogène.
Gac, Sébastien. "Modélisation numérique 3D des caractéristiques physiques des segments de dorsale lente." Phd thesis, Université de Bretagne occidentale - Brest, 2002. http://tel.archives-ouvertes.fr/tel-00008837.
Full textHorning, Gregory (Gregory William). "Geophysical and geochemical constraints on the evolution of oceanic lithosphere from formation to subduction." Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/108908.
Full textCataloged from PDF version of thesis.
Includes bibliographical references (pages 104-115).
This thesis investigates the evolution of the oceanic lithosphere in a broad sense from formation to subduction, in a focused case at the ridge, and in a focused case proximal to subduction. In general, alteration of the oceanic lithosphere begins at the ridge through focused and diffuse hydrothermal flow, continues off axis through low temperature circulation, and may occur approaching subduction zones as bending related faulting provides fluid pathways. In Chapter 2 1 use a dataset of thousands of microearthquakes recorded at the Rainbow massif on the Mid-Atlantic Ridge to characterize the processes which are responsible for the long-term, high-temperature, hydrothermal discharge found hosted in this oceanic core complex. I find that the detachment fault responsible for the uplift of the massif is inactive and that the axial valleys show no evidence for faulting or active magma intrusion. I conclude that the continuous, low-magnitude seismicity located in diffuse pattern in a region with seismic velocities indicating ultramafic host rock suggests that serpentinization may play a role in microearthquake generation but the seismic network was not capable of providing robust focal mechanism solutions to constrain the source characteristics. In Chapter 3 I find that the Juan de Fuca plate, which represents the young/hot end-member of oceanic plates, is lightly hydrated at upper crustal levels except in regions affected by propagator wakes where hydration of lower crust and upper mantle is evident. I conclude that at the subduction zone the plate is nearly dry at upper mantle levels with the majority of water contained in the crust. Finally, in Chapter 4 I examine samples of cretaceous age serpentinite sampled just before subduction at the Puerto Rico Trench. I show that these upper mantle rocks were completely serpentinized under static conditions at the Mid-Atlantic Ridge. Further, they subsequently underwent 100 Ma of seafloor weathering wherein the alteration products of serpentinization themselves continue to be altered. I conclude that complete hydration of the upper mantle is not the end point in the evolution of oceanic lithosphere as it spreads from the axis to subduction.
by Gregory Horning.
Ph. D.
Wisely, Beth, and Beth Wisely. "Geophysical and Hydrogeologic Investigations of Two Primary Alluvial Aquifers Embedded in the Southern San Andreas Fault System: San Bernardino and Upper Coachella Valley." Thesis, University of Oregon, 2012. http://hdl.handle.net/1794/12427.
Full textGuichet, Xavier. "Etude expérimentale des propriétés électriques des roches; potentiels d'électrofiltration, suivi des mouvements de fluides en zones hydrothermales." Phd thesis, Université Paris-Diderot - Paris VII, 2002. http://tel.archives-ouvertes.fr/tel-00148804.
Full textDes mesures de coefficients de couplage PS mesurés sur le terrain, et des analyses géochimiques de fluides ont été regroupées, et comparées à l'ensemble des données de laboratoire. L'ordre de grandeur des mesures de terrain coïncide avec l'ordre de grandeur de mesures de laboratoire, lorsque les mesures PS sont faites à proximité de sources. Sinon plusieurs hypothèses, reflétant souvent des modèles géologiques très différents, peuvent être avancées pour imputer l'origine du signal PS à des circulations de fluides ayant été échantillonnées régionalement. Finalement un suivi géochimique des fluides est indispensable pour interpréter correctement les données d'électrofiltration.
Enfin nous avons suivi l'électrofiltration lors de précipitation de calcite, dans la gamme de pH 4 à 12 et montré que l'électrofiltration change de signe sous certaines conditions, et interprété ces mesures par une modélisation de la triple-couche électrique [Guichet et al., G. J. I., 2006].
Socquet, Anne. "Accommodation du mouvement relatif entre l'Inde et la Sonde depuis la faille de Sagaing (Birmanie) jusqu'à la Syntaxe Est Himalayenne." Phd thesis, Université Paris Sud - Paris XI, 2003. http://tel.archives-ouvertes.fr/tel-00006110.
Full textJ'ai utilisé une approche pluridisciplinaire, basée sur la combinaison de la géodésie spatiale et de la géologie structurale, pour répondre à ces questions. Le GPS (Global Positioning System) permet de quantifier les déplacements relatifs des plaques ainsi que les mouvements intra-continentaux instantanés. La cartographie de failles à partir d'images satellitaires et les données structurales de terrain permettent d'identifier les structures tectoniques sur lesquelles ces déplacements ont été accommodés au cours du temps, ainsi que le type de déformation qui leur est associé.
J'ai pu contraindre le pôle de rotation entre les plaques Inde et Sonde. Leur mouvement relatif à la frontière n'est pas accommodé sur une seule faille isolée, mais sur plusieurs structures discrètes affectant une bande large d'environ 500 km, correspondant géographiquement à la Birmanie. La faille de Sagaing, intersismiquement bloquée, n'accommode que 18 mm/an en décrochement dextre. La partie restante de la déformation est sans doute prise dans le prisme indo-birman, aussi bien en décrochement qu'en chevauchement.
Au nord, le système partitionné birman se connecte à la Syntaxe Est Himalayenne. La transition entre ces deux systèmes est assurée, au Yunnan Occidental (Chine), par la rotation de microblocs le long de failles sénestres NE-SW, depuis le pliocène.
Auparavant, entre l'éocène et le miocène, la zone de cisaillement Shan Scarp - Gaoligong Shan constituait la limite majeure dextre entre l'Inde et l'Indochine tandis que les massifs de l'Ailao / Diangcan Shan et de la Chong Shan étaient cisaillés en sénestre, autorisant un déplacement du bloc Indochinois vers le SE.
Chambon, Guillaume. "Caractérisation expérimentale du frottement effectif des zones de faille." Phd thesis, Université Paris Sud - Paris XI, 2003. http://tel.archives-ouvertes.fr/tel-00006613.
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