Solving elastodynamics in a fluid–solid heterogeneous sphere: a parallel spectral element approximation on non-conforming grids

Chaljub, Emmanuel; Capdeville, Yann; Vilotte, J. P.

doi:10.1016/s0021-9991(03)00119-0

Cited by 145 publications

(134 citation statements)

References 57 publications

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“…Komatitsch and Vilotte (1998) and Komatitsch and Tromp (1999) provide a detailed introduction to the SEM for 3D seismic-wave propagation. The method has been subsequently applied in many areas of seismology (see, e.g., Komatitsch et al [2002], [2004] and Chaljub et al [2003]). The biggest challenge for the successful application of the SEM in the case of complex geological structures lies in the design of the mesh (Komatitsch et al, 2005).…”

Section: Introductionmentioning

confidence: 99%

Effects of Realistic Surface Topography on Seismic Ground Motion in the Yangminshan Region of Taiwan Based Upon the Spectral-Element Method and LiDAR DTM

Lee¹,

Chan²,

Komatitsch³

et al. 2009

Bulletin of the Seismological Society of America

129

101

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We combine light detection and ranging (LiDAR) digital terrain model (DTM) data and an improved mesh implementation to investigate the effects of highresolution surface topography on seismic ground motion based upon the spectralelement method. In general, topography increases the amplitude of shaking at mountain tops and ridges, whereas valleys usually have reduced ground motion, as has been observed in both records from past earthquakes and numerical simulations. However, the effects of realistic topography on ground motion have not often been clearly characterized in numerical simulations, especially the seismic response of the true ground surface. Here, we use LiDAR DTM data, which provide two-meter resolution at the free surface, and a spectral-element method to simulate three-dimensional (3D) seismic-wave propagation in the Yangminshan region in Taiwan, incorporating the effects of realistic topography. A smoothed topographic map is employed beneath the model surface in order to decrease mesh distortions due to steep ground surfaces. Numerical simulations show that seismic shaking in mountainous areas is strongly affected by topography and source frequency content. The amplification of ground motion mainly occurs at the tops of hills and ridges whilst the valleys and flat-topped hills experience lower levels of ground shaking. Interaction between small-scale topographic features and high-frequency surface waves can produce unusually strong shaking. We demonstrate that topographic variations can change peak ground acceleration (PGA) values by 50% in mountainous areas, and the relative change in PGA between a valley and a ridge can be as high as a factor of 2 compared to a flat surface response. This suggests that high-resolution, realistic topographic features should be taken into account in seismic hazard analysis, especially for densely populated mountainous areas.

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Section: Introductionmentioning

confidence: 99%

Effects of Realistic Surface Topography on Seismic Ground Motion in the Yangminshan Region of Taiwan Based Upon the Spectral-Element Method and LiDAR DTM

Lee¹,

Chan²,

Komatitsch³

et al. 2009

Bulletin of the Seismological Society of America

129

101

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“…As in any FEM, the mesh needs to be geometrically conforming, i.e., the six sides of each hexahedral element must match up exactly with the sides of neighboring elements. Let us also mention that the SEM can be adapted to geometrically non-conforming meshes based on the so-called 'mortar' matching method [e.g., Chaljub, 2000;Chaljub et al, 2003], and that such non-conforming meshes can be coupled with other numerical or quasi-analytical techniques, such as normal-mode summation ], but this is beyond the scope of this article.…”

Section: Design Of the Meshmentioning

confidence: 99%

“…Such effects have been included in the SEM and lead to additional terms in the weak formulation (19). These terms were introduced in Chaljub [2000], Komatitsch and Tromp [2002b], Chaljub et al [2003] and Chaljub and Valette [2004], and the corresponding effects on seismic waves were carefully benchmarked. We summarize these results in the following sections for completeness.…”

Section: The Weak Form Of the Seismic Wave Equationmentioning

confidence: 99%

“…The SEM has been used for two decades in computational fluid dynamics [Patera, 1984]. It has more recently been applied to problems related to two-dimensional (2-D) [Cohen et al, 1993;Priolo et al, 1994] and 3-D local or regional [Komatitsch, 1997;Faccioli et al, 1997;Komatitsch and Vilotte, 1998;Seriani, 1998;Komatitsch and Tromp, 1999;Komatitsch et al, 2004;Liu et al, 2004] and global [Chaljub, 2000;Komatitsch and Tromp, 2002a, b;Komatitsch et al, 2002;Chaljub et al, 2003;Chaljub and Valette, 2004] seismic wave propagation. We introduce the full complexity of the 3-D Earth, i.e., lateral variations in compressionalwave speed, shear-wave speed, and density in the mantle, a 3-D crustal model, anisotropy, ellipticity, surface topography and bathymetry, as well as the effects of the oceans, rotation, and self-gravitation.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

The spectral-element method in seismology

Komatitsch

Tsuboi

Tromp

2005

Seismic Earth: Array Analysis of Broadband Seismograms

120

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We present the main properties of the spectral-element method, which is well suited for numerical calculations of synthetic seismograms for three-dimensional Earth models. The technique is based upon a weak formulation of the equations of motion and combines the flexibility of a finite-element method with the accuracy of a pseudospectral method. The mesh is composed of hexahedral elements and honors the main discontinuities in the Earth model. The displacement vector is expressed in each element in terms of high-degree Lagrange interpolants, and integrals are computed based upon Gauss-Lobatto-Legendre quadrature, which leads to an exactly diagonal mass matrix and therefore drastically simplifies the algorithm. We use a fluid-solid coupling formulation that does not require iterations at the core-mantle or inner-core boundaries. The method is efficiently implemented on parallel computers with distributed memory based upon a message-passing methodology. We present two large-scale simulations for a realistic three-dimensional Earth model computed on the Japanese Earth Simulator at periods of 5 s and longer.

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“…The seismic records are generated using the spectral element method (SEM), a numerical method that can synthesize the complete wavefield, has very little intrinsic numerical dispersion, and can incorporate exactly the effect of three-dimensional variations [Komatitsch and Vilotte, 1998;Komatitsch et al, 2002;Chaljub et al, 2003]. This is a very accurate, although costly, numerical method.…”

Section: Newsmentioning

confidence: 99%

Eos, Transactions, American Geophysical Union Volume 87, Number 46, 14 November 2006

2006

EoS Transactions

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Solving elastodynamics in a fluid–solid heterogeneous sphere: a parallel spectral element approximation on non-conforming grids

Cited by 145 publications

References 57 publications

Effects of Realistic Surface Topography on Seismic Ground Motion in the Yangminshan Region of Taiwan Based Upon the Spectral-Element Method and LiDAR DTM

Effects of Realistic Surface Topography on Seismic Ground Motion in the Yangminshan Region of Taiwan Based Upon the Spectral-Element Method and LiDAR DTM

The spectral-element method in seismology

Eos, Transactions, American Geophysical Union Volume 87, Number 46, 14 November 2006

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