Linearized 2.5-dimensional parameter imaging inversion in anisotropic elastic media

Foss, S. K.; Hoop, Maarten V. de; Ursin, Bjørn

doi:10.1111/j.1365-246x.2005.02599.x

Cited by 11 publications

(6 citation statements)

References 41 publications

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“…Such analyses are presented for elastic media in Aki (1985a, 1985b), Tarantola (1986), and Forgues and Lambaré (1997) and for attenuating media in Sato (1984) and Ribodetti and Virieux (1996). Scattering patterns in elastic anisotropic transverse isotropic media are developed by Eaton and Stewart (1994), Burridge et al (1998), Bostock (2003), Foss et al (2005), and Calvet et al (2006), who show that the scattering pattern depends on the angle between the incidentwave propagation direction and the symmetry axis and on the angle between the scattered-wave polarization and the symmetry axis. More qualitative analyses of the sensitivity of the waveform inversion to the parameterization have also been proposed from the numerical computation of the finite-frequency sensitivity kernels of the waveform inversion (Sieminski et al, 2009;Greenhalgh, 2009, 2011).…”

Section: Introductionmentioning

confidence: 97%

Which parameterization is suitable for acoustic vertical transverse isotropic full waveform inversion? Part 1: Sensitivity and trade-off analysis

et al. 2013

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In most geologic environments, accounting for anisotropy is necessary to perform acoustic full waveform inversion (FWI) of wide-azimuth and wide-aperture seismic data because of the potential dependence of wave speeds on the direction of the wave propagation. In the framework of multiparameter FWI, the subsurface parameterization controls the influence of the different parameter classes on the modeled seismic data as a function of the scattering angle and hence the resolution with which the parameters can be reconstructed and the potential trade-off between different parameters. We have evaluated a numerical procedure based on computation of the scattering patterns of the different parameters to assess the sensitivity of the seismic data to different parameterizations of vertical transverse isotropic media in the acoustic approximation. Among the different categories we have tested, a monoparametric FWI was found for imaging one wave speed with a broad wavenumber content, keeping the Thomsen parameters fixed, which have a small influence on the data relative to the wave speed. This raises the question of the initial information required in the background models of the Thomsen parameters to perform reliable monoparameter FWI. Alternatively, simultaneously inverting the horizontal and vertical wave speeds introduces limited trade-off effects because these wave speeds have significant influence on the data for distinct ranges of scattering angles, while the influence of the Thomsen parameter δ remains weak. With such parameterization, the short-to-intermediate wavelengths of the vertical velocity are updated from the short-tointermediate scattering angles, while the long-to-intermediate wavelengths of the horizontal velocity are updated from the wide-to-intermediate scattering angles. We concluded that the choice of the subsurface parameterization can be driven by the acquisition geometry, which controls the scattering-angle coverage and hence the resolving power of FWI, and by the accuracy of the available initial FWI models.

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Section: Introductionmentioning

confidence: 97%

Which parameterization is suitable for acoustic vertical transverse isotropic full waveform inversion? Part 1: Sensitivity and trade-off analysis

et al. 2013

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“…Second, the problem of inverting for laterally varying general anisotropy (defined by 21 independent elastic parameters) is ill posed (e.g. De Hoop et al 1999; Foss et al 2005).…”

Section: Introductionmentioning

confidence: 99%

Wave-equation shear wave splitting tomography

Long¹,

Hoop²,

Hilst³

2008

Geophysical Journal International

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S U M M A R YThe main focus of this paper is the development of a theoretical framework for the tomographic inversion of (broad-band) shear wave splitting measurements in terms of anisotropic structure in the upper mantle. We show that the partial differential equations (PDEs) that govern wave equation shear wave splitting tomography are, upon linearization with the Born approximation, similar in structure to the equations that describe wave equation transmission and reflection tomography. For full broad-band analysis these PDEs can be evaluated numerically, but we show here the leading order asymptotic (i.e. 'ray born') behaviour of the associated finite-frequency sensitivity kernels. For simplicity we assume that the anisotropic model is invariant in one horizontal direction. This 2.5-D geometry is well suited for studying upper-mantle anisotropy associated with subduction of lithospheric plates if the trench-slab system is approximately 2-D. With the so-called splitting intensity as the metric for data fit, and under the assumption of weak anisotropy, we derive expressions for the sensitivity kernels. We focus on two anisotropic parameters that describe tilted transverse isotropy: the dip θ 0 of the symmetry axis with respect to the horizontal plane and the anellipticity parameter A , which represents the strength of the anisotropy. We illustrate the finite-frequency effects both for homogeneous and heterogeneous (anisotropic) background models. The sensitivity kernels in heterogeneous media are calculated for initial models obtained from numerical modelling of flow and finite strain beneath the Ryukyu arc. Kernels calculated in heterogeneous media differ substantially from those in a homogeneous background. This demonstrates the importance of iterative model (and kernel) assessment for reaching the full (resolution) potential of finite frequency tomography.

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“…For instance, the faster approximate results obtained by the application of the 2.5-D approach can be used as initial models for the complex 3-D studies to reduce the overall cost. As pointed out by, for example, Foss et al (2005), ocean bottom seismic observations along individual lines benefit from the principles of the 2.5-D interpretation.…”

Section: Discussion a N D C O N C L U S I O N Smentioning

confidence: 99%

Forward modelling the multiply scattered 2.5-D teleseismicPwaves accelerated by the multilevel fast multipole method

Çakır

2009

Geophysical Journal International

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S U M M A R YThe present study introduces an algorithm to compute the forward modelling of multiple scattering. The propagating medium is defined, in general, by 3-D heterogeneities embedded in a 1-D layered structure, assumed as the reference structure. The 3-D formulation is consequently modified to suit 2.5-D scattering modelling. The basic formulation relies on the Green's function method and employs (1) the reflectivity method (RM) to acquire the 1-D multilayered, half-space Green's function, (2) the multilevel fast multipole method (MLFMM) to gain speed and (3) the generalized minimal residual method (GMRES) to iteratively solve the linear system in a memory efficient manner. The heterogeneities are modelled as point scatterers, creating a secondary wavefield that superimposes on the waves in the reference structure. The algorithm is efficient since the CPU time increases logarithmically with the size of the model. The test cases included various anomalous lithosphere structures, ranging from a simple point scatterer to a suture zone.

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Linearized 2.5-dimensional parameter imaging inversion in anisotropic elastic media

Cited by 11 publications

References 41 publications

Which parameterization is suitable for acoustic vertical transverse isotropic full waveform inversion? Part 1: Sensitivity and trade-off analysis

Which parameterization is suitable for acoustic vertical transverse isotropic full waveform inversion? Part 1: Sensitivity and trade-off analysis

Wave-equation shear wave splitting tomography

Forward modelling the multiply scattered 2.5-D teleseismicPwaves accelerated by the multilevel fast multipole method

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