Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1992. / Vita. Abstract. Includes bibliographical references (leaves 97-99). Also available via the Internet.

Thesis (Ph. D.)--University of Washington, 1998. / Vita. Includes bibliographical references (p. [148]-158).

Thesis (Ph. D.)--University of Washington, 2004. / Vita. Includes bibliographical references (p. 127-134).

Thesis (Ph. D.)--University of Washington, 1996. / Vita. Includes bibliographical references (leaves [137]-146).

Thesis (Ph. D.)--California Institute of Technology, 1986. / Includes bibliographical references (leaves 215-228).

Thesis (Ph. D.)--University of Texas at Austin, 2007. / Vita. Includes bibliographical references.

Thesis (Ph. D.)--Brigham Young University. Dept. of Civil and Environmental Engineering, 2006. / Includes bibliographical references (p. 263-270).

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Orientador: Martin Tygel / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica e Instituto de Geociências / Made available in DSpace on 2018-08-27T15:05:45Z (GMT). No. of bitstreams: 1 Vasconcelos_TabajaraWilliamsVilela_M.pdf: 7596247 bytes, checksum: 87f367837309475d85211f828eb1929f (MD5) Previous issue date: 2015 / Resumo: Dados sísmicos dispostos em grades densas e regulares são essenciais em vários objetivos de processamento, imageamento e inversão. Exemplos de tais objetivos incluem a eliminação de múltiplas de superfície (SRME) e migração baseada na equação da onda (WEM). Dados de sísmica de reflexão são geralmente sub-amostrados e as razões para isso incluem limitações físicas (por exemplo, comprimento finito dos cabos, dificuldades topográficas e ambientais), falhas instrumentais (por exemplo, traços ruins ou inexistentes) e, acima de tudo, a amostragem espacial densa é cara. Para superar o problema de subamostragem, bem como os deslocamentos dos dados da malha regular, é necessário reconstruir os dados faltantes a partir dos dados adquiridos. Em outras palavras, é preciso realizar interpolação e/ou extrapolação dos dados existentes. Este trabalho discute e compara métodos de interpolação e extrapolação com base na abordagem da superfície de reflexão comum (CRS), que se baseia num certo número de atributos cinemáticas das ondas de propagação, obtidos a partir dos dados de multicobertura. A análise é realizada em três metodologias CRS, a saber: (a) empilhamento parcial (PS) CRS; (b) regularização orientada à amostra alvo (TO) CRS e (c) regularização orientada ao operador (OO) CRS. Uma breve descrição das três metodologias é realizada e, por meio de exemplos ilustrativos, examinamos suas vantagens e desvantagens / Abstract: Dense and regularly sampled seismic data are essential to a number of processing, imaging and inversion purposes. Processes such as Surface-Related Multiple Elimination (SRME) and wave-equation migration (WEM) are good examples that required data displayed on a regular grid. Seismic reflection data are usually under or irregularly sampled. Reasons for that include physical limitations (e.g., finite-length spread, topographic or environmental difficulties), instrumental failures (e.g., bad or dead traces). Above all, dense spatial sampling is expensive. To overcome the under sampling problem, as well of having the data displaced on regular grids, it is necessary to simulate the missing data from the acquired data. In other words, one needs to interpolate and/or extrapolate the given data to a user defined regular grid. This work discusses and compares interpolation and/or extrapolation methods based on the common-reflection-surface (CRS) approach, which is based on a number of kinematic wavefield attributes, extracted from the multicoverage data. The analysis will be carried out on three CRS methodologies, namely (a) the partial-stack (PS) CRS; (b) the target-oriented (TO) CRS and (c) the operator-oriented (OO) CRS. We provide a brief description of the three methodologies and, by means of illustrative examples, examine their advantages and disadvantages / Mestrado / Reservatórios e Gestão / Mestre em Ciências e Engenharia de Petróleo

I present new models of the elastic structure of the Pacific upper mantle that address the formation and evolution of oceanic plates. Using a surface-wave dispersion dataset, I perform anisotropic tomography to construct two-dimensional phase-velocity maps and three-dimensional velocity models of the Pacific basin. My three-dimensional elastic models describe both the radial and azimuthal anisotropy of seismic waves. In order to constrain these models, I develop regularization techniques that incorporate a priori information about the nature of the oceanic upper mantle, including both the age dependence of seismic velocities and the expected scaling relationships between azimuthal anisotropy parameters derived from realistic peridotite elastic tensors. I observe a strong cooling signal in the upper-mantle seismic velocities that is consistent with halfspace cooling of the lithospheric plate; deviations from this simple cooling signature are related to the influence of mantle plumes or other thermal alteration of the lithosphere. As plate age increases, the depth to the thermally controlled lithosphere-asthenosphere boundary increases as well. This thermal boundary, as seen in the negative gradient in seismic velocities, is consistent with the depth at which there is a transition in anisotropy fast-axis orientation. This change in anisotropy orientation is due to the transition from frozen-in lithospheric anisotropy to asthenospheric anisotropy that is related to geologically recent shear beneath the base of the plate. The anisotropy orientations and strength that we observe throughout the plate are only consistent with A-type olivine fabric. There are regions where anisotropy orientations do not align with paleospreading directions in the lithosphere or absolute-plate-motion in the asthenosphere, suggesting that small-scale convection, mantle flow, and plumes could all lead to changes in the orientation of seismic anisotropy. There is a dependence on the strength of anisotropy on spreading rate at shallow depths; this implies that corner flow at faster-spreading ridges is more effective at aligning olivine crystals in the direction of shear. I also present a new set of local surface-wave amplification maps spanning the contiguous United States. I perform a synthetic-tomography experiment in order to assess our ability to resolve variations in surface-wave amplification due to variations in local elastic structure. Local amplification derived from synthetic seismograms is very highly correlated with direct predictions of amplification, suggesting that we are able to resolve this signal well and that local amplification observations reflect elastic structure local to the station on which they are measured. Local amplification can be used as a complementary constraint to phase velocity in order to map upper-mantle elastic structure.