Accurate and efficient modeling of global seismic wave propagation for an attenuative Earth model including the center

Toyokuni, Genti; Takenaka, Hiroshi

doi:10.1016/j.pepi.2012.03.010

Cited by 11 publications

(11 citation statements)

References 54 publications

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“…With the second-order central differencing method, the MHD_Spectral code is computed by a hybrid Fourier spectral [16,17], and the MHD_FDM code is computed by the 12th order accurate finite difference method [18]. QSFDM_GLOBE This code simulates global seismic wave fields generated by a moment-tensor point source [19]. It solves a 3D wave equation in spherical coordinates on a 2D structural cross section, assuming that the structure is rotationally symmetric about the vertical axis including the source, so called axisymmetric 2.5D modeling.…”

Section: Bcm (Building-cube Method)mentioning

confidence: 99%

Potential of a modern vector supercomputer for practical applications: performance evaluation of SX-ACE

et al. 2017

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Achieving a high sustained simulation performance is the most important concern in the HPC community. To this end, many kinds of HPC system architectures have been proposed, and the diversity of the HPC systems grows rapidly. Under this 123Potential of a modern vector supercomputer for practical… 3949 circumstance, a vector-parallel supercomputer SX-ACE has been designed to achieve a high sustained performance of memory-intensive applications by providing a high memory bandwidth commensurate with its high computational capability. This paper examines the potential of the modern vector-parallel supercomputer through the performance evaluation of SX-ACE using practical engineering and scientific applications. To improve the sustained simulation performances of practical applications, SX-ACE adopts an advanced memory subsystem with several new architectural features. This paper discusses how these features, such as MSHR, a large on-chip memory, and novel vector processing mechanisms, are beneficial to achieve a high sustained performance for large-scale engineering and scientific simulations. Evaluation results clearly indicate that the high sustained memory performance per core enables the modern vector supercomputer to achieve outstanding performances that are unreachable by simply increasing the number of fine-grain scalar processor cores. This paper also discusses the performance of the HPCG benchmark to evaluate the potentials of supercomputers with balanced memory and computational performance against heterogeneous and cutting-edge scalar parallel systems.

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Section: Bcm (Building-cube Method)mentioning

confidence: 99%

Potential of a modern vector supercomputer for practical applications: performance evaluation of SX-ACE

et al. 2017

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“…In a spherical polar coordinate system (r, θ, φ) (Fig. 2), the velocity-stress form of the 3-D isotropic linear elastodynamic equation may be written as (e.g., Igel et al 2002;Toyokuni et al 2012):…”

Section: Methodsmentioning

confidence: 99%

“…(8), (9) and (7) (hereafter called "quasi-Cartesian FDTD"), while those for the flat model are obtained by using the equations without the additional terms and assuming constant Δx and Δy (hereafter called "Cartesian FDTD"). In the first numerical example, we check the accuracy and validity of the quasi-Cartesian scheme by comparing the synthetic seismograms with those obtained by the spherical FDTD (Toyokuni and Takenaka 2012) which treats an axisymmetric global model including the center of the sphere in (11) = arctan sin δ sin ε + cos δ sin α cos ε cos δ cos α , β = arcsin(sin δ cos ε − cos δ sin α sin ε).…”

Section: Numerical Examplesmentioning

confidence: 99%

Quasi-Cartesian finite-difference computation of seismic wave propagation for a three-dimensional sub-global model

Takenaka

Komatsu

Toyokuni

et al. 2017

Earth Planets Space

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A simple and efficient finite-difference scheme is developed to calculate seismic wave propagation in a partial spherical shell model of a three-dimensionally (3-D) heterogeneous global Earth structure for modeling on regional or sub-global scales where the effects of the Earth's spherical geometry cannot be ignored. This scheme solves the elastodynamic equation in the quasi-Cartesian coordinate form similar to the local Cartesian one, instead of the spherical polar coordinate form, with a staggered-grid finite-difference method in time domain (FDTD) that is one of the most popular numerical methods in seismic-motion simulations for local-scale models. The proposed scheme may be a local-friendly approach for modeling on a sub-global scale to link regional-scale and local-scale simulations. It can be easily implemented using an available 3-D Cartesian FDTD local-scale modeling code by changing a very small part of the code. We implement the scheme in an existing Cartesian FDTD code and demonstrate the accuracy and validity of the present scheme and the feasibility to apply it to real large simulations through numerical examples.

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“…Axisymmetric finite difference methods (Toyokuni and Takenaka, 2006;Jahnke et al, 2008) may accommodate this effectively, but suffer various shortcomings such as approxi-mate sources, lack of fluid domains and anisotropy (Jahnke et al, 2008), and high dispersion errors for large propagation distances of interface-sensitive phases such as surface or diffracted waves. However, recent advances include a full moment tensor, attenuation, and the Earth's center (Toyokuni and Takenaka, 2012).…”

Section: -D Waves In Axisymmetric Mediamentioning

confidence: 99%

AxiSEM: broadband 3-D seismic wavefields in axisymmetric media

Nissen‐Meyer¹,

Driel²,

Stähler³

et al. 2014

Preprint

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Abstract. We present a methodology to compute 3-D global seismic wavefields for realistic earthquake sources in visco-elastic anisotropic media, covering applications across the observable seismic frequency band with moderate computational resources. This is accommodated by mandating axisymmetric background models which allow for a multipole expansion such that only a 2-D computational domain is needed, whereas the azimuthal third dimension is computed analytically on-the-fly. This dimensional collapse opens doors for storing space-time wavefields on disk which can be used to compute Fréchet sensitivity kernels for waveform tomography. We use the corresponding publicly available open-source spectral-element code AxiSEM (http://www.axisem.info), demonstrate its excellent scalability on supercomputers, a diverse range of applications ranging from normal modes to small-scale lowermost mantle structures, tomographic models, comparison to observed data, and discuss further avenues to pursue with this methodology.

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Accurate and efficient modeling of global seismic wave propagation for an attenuative Earth model including the center

Cited by 11 publications

References 54 publications

Potential of a modern vector supercomputer for practical applications: performance evaluation of SX-ACE

Potential of a modern vector supercomputer for practical applications: performance evaluation of SX-ACE

Quasi-Cartesian finite-difference computation of seismic wave propagation for a three-dimensional sub-global model

AxiSEM: broadband 3-D seismic wavefields in axisymmetric media

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