VIRIEUX , J.

C027 3D Finite-Difference Frequency-Domain Modeling of Acoustic Wave Propagation Using a Massively Parallel Direct Solver H. Ben Hadj Ali* (Géosciences Azur - CNRS) S. Operto (Geosciences Azur - CNRS) J. Virieux (Géosciences Azur - UNSA) P. Amestoy (ENSEEIHT-IRIT) J.Y. L'Excellent (ENS Lyon-INRIA) & L. Giraud (ENSEEIHT-IRIT) SUMMARY We present...

In deep offshore, crustal-scale seismic imaging is classically performed by traveltime tomography applied to wide-angle seismic data recorded by a network of Ocean Bottom Seismometers (OBS). The resulting velocity model is of limited resolution. If the wide-angle experiment is multifold thanks to densely sampled OBSs, this large-scale velocity...

The deployment of a worldwide network for infrasound detection requires numerical methods for modeling these signals over long distances. A ray theoretical approach appears robust and efficient. It furthermore allows a straightforward interpretation of recorded phases. We have developed a three-dimensional Hamiltonian ray tracing for modeling...

We present a 3D frequency-domain finite-difference method for acoustic wave propagation modeling. This method is developed as a tool to perform 3D frequency-domain full-waveform inversion of wide-angle seismic data. For wide-angle data, frequency-domain full-waveform inversion can be applied only to few discrete frequencies to develop reliable...

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Two-dimensional (2-D) modelling of dynamic seismic rupture is performed using a recent staggered-grid finite-difference formulation. Rupture boundary conditions are applied only inside the crack, without assuming any symmetry with respect to the rupture surface. By a simple rotation of the stress tensor, the local orientation of the crack is...

Many studies have been performed to analyse the presence of gas hydrate through the observation of bottom- simulating reflectors (BSR). Much of the available information has come from seismic reflection data calibrated by limited in situ (drilling, borehole) data. Numerous studies involving forward modeling and inversion of multichannel seismic...

In offshore surveys, the deep crust is generally investigated by traveltime tomography applied to sparse ocean bottom seismometer data. The inferred velocity models are of limited resolution precluding a quantitative analysis of deep tectonic discontinuities. If dense arrays of ocean bottom seismometers can be deployed, the resulting data sets...

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We investigate finite-frequency effects in local tomography. For this purpose, we developed an inversion method including the sensitivity kernels in an 3D tomographic method. The influence of the frequency content is analyzed when considering variable velocity structure. Both travel-time and amplitude estimations are required to compute the...

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We present a distributed-memory parallel algorithm for 2D visco-acoustic full-waveform inversion of wide-angle seismic data. Our code is written in fortran90 and use MPI for parallelism. The algorithm was applied to real wide-angle data set recorded by 100 OBSs with a 1-km spacing in the eastern-Nankai trough (Japan) to image the deep structure...

We propose here a method for maging near-surface structures although it can nevertheless be applied for deeper areas characterization. We perform the elastic full waveform inversion in the frequency domain in order to recover physical properties of the medium from both body waves and surfaces waves. We first present the forward problem and then...

Geophysical Journal International, v. 152, n. 2, p. 486-496, 2003. http://dx.doi.org/10.1046/j.1365-246X.2003.01864.x

We have implemented a finite-difference algorithm for image-wave time-remigration in FORTRAN~90, and studied its theoretical properties in detail. For a numberof synthetic models, numerical experiments have been realized. For these examples, we obtained perfect agreement between the theoretical predictions and numerical results. The examples...

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An investigation of the teleseismic P-wave coda is performed using the single-scattering approximation. The method allows one to image short-wavelength scale (≤2 km) velocity and density heterogeneities and structures that are barely detected by traveltime tomography. Source effects are removed by using receiver functions for data...

Elastic frequency-domain full-waveform inversion is here applied to a realistic synthetic offshore model to study the behavior of the least-squares and least-absolute-value norms, in the presence of noisy multi-component seis- mic data. As expected, the inversion results show that the L2 norm is highly sensitive to non-Gaussian errors in the...

We compare different finite-difference schemes for two-dimensional (2-D) acoustic frequencydomain forward modelling. The schemes are based on staggered-grid stencils of various accuracy and grid rotation strategies to discretize the derivatives of the wave equation. A combination of two O(x 2) staggered-grid stencils on the classical Cartesian...

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Stress and fluid transfers were analyzed on the surface of a 30 m thick dextral strike-slip fault zone subjected to an overpressure of 63 kPa. Pressure-strain measurements taken during the pressurization indicated a strain state primarily controlled by the hydromechanical behavior of permeable fractures, and then, by the fluid diffusion in the...