Seismic Anisotropy
Mostrando 1-11 de 11 artigos, teses e dissertações.
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1. Modelagem física de meios fraturados anisotrópicos e estudo da birrefringência sísmica em função dos parâmetros anisotrópicos / Physical modeling of anisotropic fractured media and study of seismic splitting as a function of the anisotropic parameters
Meios anisotrópicos fissurados ou fraturados têm sido amplamente investigados em muitos estudos teóricos e experimentais. Neste trabalho, realizamos uma série de medidas ultrassônicas objetivando investigar o comportamento de diferentes meios artificialmente anisotrópicos. Três questões foram abordadas: (1) estudo da birrefringência da onda S em fun
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 05/03/2012
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2. Cálculo dos coeficientes de reflexão e transmissão em meios anisotrópicos / Calculation of the reflection and transmission coefficients in anisotropic media
A maioria dos métodos de imageamento de subsuperfície aplicados em projetos de Exploração e Produção (E&P) de hidrocarbonetos assume o meio elástico isotrópico (ISO). Os meios isotrópicos, em contrapartida aos modelos anisotrópicos, são aqueles cujas velocidades das ondas sísmicas não dependem da direção de propagação. Entretanto, muitas roc
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 16/07/2010
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3. Propriedades sísmicas anisotrópicas derivadas da orientação cristalográfica preferencial de muscovita-quartzo milonitos
Seismic wave propagation in organized matter usually results in azimuthal variations of longitudinal waves (Pwaves), as well as the effect of birefringence in transversal waves (S-waves), which results in two orthogonal shear waves with contrasting velocities. In this paper we present the results of the anisotropic seismic properties of five samples of musco
Publicado em: 2010
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4. Tempo de transito em meios com isotropia transversal vertical (VTI) : aproximações e inversão dos parametros / Traveltime in vertical transversely isotropic (VTI) media : approximations and parameters inversion
As exploration targets have become deeper, cable lengths have increased accordingly, making the conventional two term hyperbolic traveltime approximation produce increasingly erroneous traveltimes. In other words, for modern long-offset acquisition geometries, a hyperbolic traveltime approximation is no longer sufficient to flatten the CMP gather because of
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 03/08/2009
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5. Anisotropia sísmica crustal na região de Cascavel - CE
This dissertation presents a study on crustal seismic anisotropy in Cascavel - CE. The earthquake data employed here are from the Seismological Laboratory at Universidade Federal do Rio Grande do Norte (UFRN) and were colected from 29 September 1997 to 05 march 1998 using six three-component digital seismographic stations. In general, the cause of the observ
Publicado em: 2007
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6. As equações da onda imagem para remigração em meios elipticamente anisotropicos / The image wave equations for remigration in elliptically anisotropic media
The image-wave equations for the problems of depth and time remigration in elliptically anisotropic media are second-order partial differential equations similar to the acoustic wave equation. The propagation variable is the vertical velocity or the medium ellipticity. These differential equations are derived from the kinematic properties of anisotropic remi
Publicado em: 2007
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7. ANISOTROPY INFLUENCE ON NORMAL MOVEOUT CORRECTION IN VTI SEISMIC DATA AND VELOCITY ANALYSIS USINGGRADIENT DESCENDENT / INFLUÊNCIA DA ANISOTROPIA VTI NA CORREÇÃO DE SOBRETEMPO NORMAL EM DADOS SÍSMICOS E ANÁLISE DE VELOCIDADE POR GRADIENTE DESCENDENTE
This work quantifies the error created during seismic processing when isotropic approach is used to normal moveout correction and velocity analysis and the seismic data is anisotropic. This quantification is made by performing velocity analysis in several synthetic seismograms built from a simple (but realistic) geological model with some horizontal layers,
Publicado em: 2005
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8. Estudo sísmico no açude Tucunduba, Senador Sá, CE
The Tucunduba Dam, is west of Fortaleza, Ceará State. The seismic monitoring of the area, with an analogical station and seven digital stations, had beginning on June 11, 1997. The digital stations, operated from June to November 1997. The data collected in the period of digital monitoring was analyzed for determination of hypocenters, focal mechanisms, and
Publicado em: 1999
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9. Mantle dynamics and seismic tomography
Three-dimensional imaging of the Earth's interior, called seismic tomography, has achieved breakthrough advances in the last two decades, revealing fundamental geodynamical processes throughout the Earth's mantle and core. Convective circulation of the entire mantle is taking place, with subducted oceanic lithosphere sinking into the lower mantle, overc
The National Academy of Sciences.
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10. The innermost inner core of the earth: Evidence for a change in anisotropic behavior at the radius of about 300 km
Since the discovery of the inner core in 1936, no additional spherical subshell of the Earth has been observed. Based on an extensive seismic data set, we propose the existence of an innermost inner core, with a radius of ∼300 km, that exhibits a distinct transverse isotropy relative to the bulk inner core. Specifically, within the innermost inner core, th
National Academy of Sciences.
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11. Shear waves in the diamond-anvil cell reveal pressure-induced instability in (Mg,Fe)O
The emerging picture of Earth's deep interior from seismic tomography indicates more complexity than previously thought. The presence of lateral anisotropy and heterogeneity in Earth's mantle highlights the need for fully anisotropic elasticity data from mineral physics. A breakthrough in high-frequency (gigahertz) ultrasound has resulted in transmission of
National Academy of Sciences.