Simulations of Ground Motion in the Los Angeles Basin Based upon the Spectral-Element Method

Komatitsch, Dimitri; Liu, Qinya; Tromp, Jeroen; Süss, Peter; Stidham, C.; Shaw, John H.

doi:10.1785/0120030077

Cited by 367 publications

(268 citation statements)

References 91 publications

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“…We use the SPECFEM3D software package developed by Komatitsch et al (2004) and decompose the study area into 224 mesh slices (224 processors) for parallel computing based upon the message-passing interface (MPI) (Gropp et al, 1996). The average distance between the GaussLobatto-Legendre integration points at the surface of the model is about 2 m, that is, small enough to resolve the LiDAR DTM data at a maximum frequency of approximately 10 Hz.…”

Section: Simulation Resultsmentioning

confidence: 99%

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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

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135

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: Simulation Resultsmentioning

confidence: 99%

“…We used the SPECFEM3D software package (available at www.geodynamics.org) developed by Komatitsch et al (2004) in this study. The LiDAR-derived DTM was reprocessed from the raw LiDAR data funded by the Central Geological Survey, Taiwan, to Y. C. Chan.…”

Section: Data and Resourcesmentioning

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

Self Cite

135

101

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“…Several studies document the importance of including realistic descriptions of surface topography to accurately reproduce seismic-wave propagation and surface ground motion (e.g., Kawase and Aki, 1990;Bouchon and Barker, 1996;Spudich et al, 1996;Komatitsch and Vilotte, 1998;Komatitsch et al, 2004;Lee et al, 2008;Lee, Chan, et al, 2009;Monteiller et al, 2013). In addition, these studies highlight the ability of the SEM to accommodate such complexity in simulations at very high resolution (e.g., Lee, Chan, et al, 2009).…”

Section: Simulations With 1d Models: Topographic Effectsmentioning

confidence: 98%

“…The implementation of this feature in the simulations is important, especially if the region of interest is characterized by low wavespeed sedimentary basins (e.g., Olsen et al, 2003;Komatitsch et al, 2004;Lee et al, 2008).…”

Section: Simulations With 1d Models: Topographic Effectsmentioning

confidence: 99%

“…If need be, the SEM can be implemented as a discontinuous Galerkin method (Kopriva et al, 2002;Kopriva, 2006;Acosta Minolia and Kopriva, 2011). The SEM has been used to study 2D and 3D local, regional, and global seismic-wave propagation problems (e.g., Cohen et al, 1993;Priolo et al, 1994;Faccioli et al, 1997;Komatitsch, 1997;Komatitsch and Vilotte, 1998;Komatitsch and Tromp, 2002a,b;Chaljub and Valette, 2004;Komatitsch et al, 2004Komatitsch et al, , 2005Liu et al, 2004;Stich and Morelli, 2007;Lee et al, 2008;Stich et al, 2009;Stupazzini et al, 2009;Tape et al, 2010;Zhu et al, 2012a,b). In particular, in the recent work of Smerzini and Villani (2012), the SEM implemented in the code GeoELSE (Stupazzini et al, 2009) has been used to simulate near-fault ground motions produced by the 2009 L'Aquila mainshock.…”

Section: Introductionmentioning

confidence: 99%

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Spectral-Element Simulations of Seismic Waves Generated by the 2009 L'Aquila Earthquake

Magnoni¹,

Casarotti²,

Michelini³

et al. 2013

Bulletin of the Seismological Society of America

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We adopt a spectral-element method (SEM) to perform numerical simulations of the complex wavefield generated by the 6 April 2009 M w 6.3 L'Aquila earthquake in central Italy. The mainshock is represented by a finite-fault solution obtained by inverting strong-motion and Global Positioning System data, testing both 1D and 3D wavespeed models for central Italy. Surface topography, attenuation, and the Moho discontinuity are also accommodated. Including these complexities is essential to accurately simulate seismic-wave propagation. Three-component synthetic waveforms are compared to corresponding velocimeter and strong-motion recordings. The results show a favorable match between data and synthetics up to ∼0:5 Hz in a 200 km × 200 km × 60 km model volume, capturing features mainly related to topography or low-wavespeed basins. We construct synthetic peak ground velocity maps that, for the 3D model, are in good agreement with observations, thus providing valuable information for seismic-hazard assessment. Exploiting the SEM in combination with an adjoint method, we calculate finite-frequency kernels for specific seismic arrivals. These kernels capture the volumetric sensitivity associated with the selected waveform and highlight prominent effects of topography on seismic-wave propagation in central Italy.

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Low wave speed zones in the crust beneath SE Tibet revealed by ambient noise adjoint tomography

Chen

Huang

Yao

et al. 2014

Geophysical Research Letters

109

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We present a refined 3D crustal model beneath SE Tibet from ambient noise adjoint tomography. Different from ray-theory-based tomography, adjoint tomography in this study incorporates a spectral-element method (SEM) and takes empirical Green's functions (EGFs) of Rayleigh waves from ambient noise interferometry as the direct observation. The frequency-dependent traveltime misfits between SEM synthetic Green's functions and EGFs are minimized with a preconditioned conjugate gradient method, meanwhile the 3D model gets improved iteratively utilizing 3D finite-frequency kernels. The new model shows 3 -6% shear wave speed increasing beneath the western Sichuan Basin (SCB) (depth > 15 km) and the central Chuan-Dian Block (CDB), and 6 -12% shear wave speed reduction in the mid-lower crust beneath the northern and the southern CDB. The inferred spatial pattern of low wave speed zones, consistent with possible partial melt, suggests more complex and disconnected geometry than the pervasive narrow zone from the channel flow models.

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Simulations of Ground Motion in the Los Angeles Basin Based upon the Spectral-Element Method

Cited by 367 publications

References 91 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

Spectral-Element Simulations of Seismic Waves Generated by the 2009 L'Aquila Earthquake

Low wave speed zones in the crust beneath SE Tibet revealed by ambient noise adjoint tomography

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