A proposal for a standard procedure of modeling 3-D velocity structures and its application to the Tokyo metropolitan area, Japan

Koketsu, Kazuki; Miyake, Hideaki; Afnimar,; Tanaka, Yasuhisa

doi:10.1016/j.tecto.2008.05.037

Cited by 75 publications

(65 citation statements)

References 26 publications

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“…Furthermore, we confirmed that the JIVSM did not reproduce the observed excitation of the long-period surface waves at the northern edge of the Kanto Basin (TCG001, TCGH06, and SIT003). In contrast, simulation results of the SBVSM accurately reproduced the observed amplitudes and arrival times (Yamamizu 1996(Yamamizu , 2004Yoshimoto and Takemura 2014a), the waveform analysis using the initial model (Figure 3), the JIVSM (Koketsu et al , 2009, and microtremor surveys (Matsuoka and Shiraishi 2002;Yamanaka et al 2005;Senna et al 2013), respectively. of surface waves at not only stations near the basin edge (GNM.059, TCGH06, TCG001, and SIT003) but also at stations far from the edge (SIT.015, SIT010, and TKY.1220).…”

Section: D Velocity Structure Model By Integration Of Local Structuresmentioning

confidence: 74%

“…In the Kanto Basin, the sedimentary structure of the JIVSM was mainly constructed using geophysical information from refraction surveys (Koketsu et al , 2009). However, the refraction surveys were not densely carried out in the northern part of the Kanto Basin compared with the middle and southern parts.…”

Section: Discussionmentioning

confidence: 99%

“…Extensive efforts to construct a 3D structure model of the Kanto Basin have been put forth by many researchers (e.g., Yamanaka and Yamada 2006;Koketsu et al , 2009Fujiwara et al 2009). Using available geophysical and geological information in Japan, Koketsu et al ( , 2009 proposed the Japan Integrated Velocity Structure Model (JIVSM), which is one of the latest and most widely used structure models for the evaluation of strong and long-period ground motions of large earthquakes (e.g., Iwaki et al 2013;Maeda et al 2013b), the estimation of rupture complexities for large earthquakes (e.g., Koketsu et al 2011;Asano and Iwata 2012), and the simulation of seismic wave scattering (e.g., Maeda et al 2014;Takemura and Yoshimoto 2014).…”

Section: Introductionmentioning

confidence: 99%

“…Using available geophysical and geological information in Japan, Koketsu et al ( , 2009 proposed the Japan Integrated Velocity Structure Model (JIVSM), which is one of the latest and most widely used structure models for the evaluation of strong and long-period ground motions of large earthquakes (e.g., Iwaki et al 2013;Maeda et al 2013b), the estimation of rupture complexities for large earthquakes (e.g., Koketsu et al 2011;Asano and Iwata 2012), and the simulation of seismic wave scattering (e.g., Maeda et al 2014;Takemura and Yoshimoto 2014). The JIVSM represents the 3D heterogeneous subsurface structure using 23 constant-velocity layers including those of the crust, the mantle, the Philippine Sea (PHS) Plate, and the Pacific (PAC) Plate, and also the complex basement shapes of sedimentary basins.…”

Section: Introductionmentioning

confidence: 99%

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Long-period ground motions in a laterally inhomogeneous large sedimentary basin: observations and model simulations of long-period surface waves in the northern Kanto Basin, Japan

et al. 2015

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To conduct practical evaluations of the long-period ground motions (period of 4 to 8 s) in a laterally inhomogeneous large sedimentary basin, we constructed a three-dimensional (3D) sedimentary velocity structure model for the northern Kanto Basin in Japan using a simple velocity gradient function, where strong lateral variations of seismic velocities in the sediments were expected. The model construction employs waveform analysis and geophysical data from vertical seismic profiling and microtremor surveys in the target region. To validate the velocity structure model, we conducted large-scale 3D finite-difference method simulations of the long-period ground motions for two shallow moderate earthquakes: the northern Tochigi earthquake and the northern Ibaraki earthquake. The simulation results for both earthquakes accurately reproduced the observed long-period ground motions in terms of arrival times, amplitudes, and durations of surface waves. By detailed comparisons of the seismograms for observational and simulated data, we demonstrated that the lateral variation of the seismic velocities in the sediments determines the characteristics of the surface wave propagation in the northern Kanto Basin. Such analyses can provide a better understanding of the complex propagation characteristics of surface waves in laterally inhomogeneous, large sedimentary basins.

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Section: D Velocity Structure Model By Integration Of Local Structuresmentioning

confidence: 74%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Long-period ground motions in a laterally inhomogeneous large sedimentary basin: observations and model simulations of long-period surface waves in the northern Kanto Basin, Japan

et al. 2015

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“…From the viewpoint of strong motion prediction, Koketsu et al (2008Koketsu et al ( , 2009) proposed a modeling procedure of a 3D wave speed structure to evaluate the ground shaking produced by an earthquake. They used various types of databases, such as geophysical experiments, gravity surveys, geological investigations, and seismic observations of natural events, to develop a layered model of the Kanto basin.…”

Section: Introductionmentioning

confidence: 99%

Adjoint tomography of the crust and upper mantle structure beneath the Kanto region using broadband seismograms

Miyoshi

Obayashi

Peter

et al. 2017

Prog Earth Planet Sci

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A three-dimensional seismic wave speed model in the Kanto region of Japan was developed using adjoint tomography for application in the effective reproduction of observed waveforms. Starting with a model based on previous travel time tomographic results, we inverted the waveforms obtained at seismic broadband stations from 140 local earthquakes in the Kanto region to obtain the P-and S-wave speeds V p and V s . Additionally, all centroid times of the source solutions were determined before the structural inversion. The synthetic displacements were calculated using the spectral-element method (SEM) in which the Kanto region was parameterized using 16 million grid points. The model parameters V p and V s were updated iteratively by Newton's method using the misfit and Hessian kernels until the misfit between the observed and synthetic waveforms was minimized. Computations of the forward and adjoint simulations were conducted on the K computer in Japan. The optimized SEM code required a total of 6720 simulations using approximately 62,000 node hours to obtain the final model after 16 iterations. The proposed model reveals several anomalous areas with extremely low-V s values in comparison with those of the initial model. These anomalies were found to correspond to geological features, earthquake sources, and volcanic regions with good data coverage and resolution. The synthetic waveforms obtained using the newly proposed model for the selected earthquakes showed better fit than the initial model to the observed waveforms in different period ranges within 5-30 s. This result indicates that the model can accurately predict actual waveforms.

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Long-period seismic amplification in the Kanto Basin from the ambient seismic field

Denolle

Miyake

Nakagawa

et al. 2014

Geophys. Res. Lett.

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Tokyo, like many seismically threatened cities, is situated atop a sedimentary basin that has the potential to trap and amplify seismic waves from earthquakes. We study amplification in the Kanto Basin by exploiting the information carried by the ambient seismic field. We use 375 seismic stations from the high sensitivity seismograph network across central Honshu as virtual sources and 296 seismic stations of the Metropolitan Seismic Observation network shallow borehole seismometers within the basin as receivers to map the basin response. We find a linear relationship between ground motion and basin depth at periods of 2–10 s that could be used to represent 3‐D basin effects in ground motion prediction equations. We also find that the strength of basin seismic amplification depends strongly on the direction of illumination by seismic waves.

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A proposal for a standard procedure of modeling 3-D velocity structures and its application to the Tokyo metropolitan area, Japan

Cited by 75 publications

References 26 publications

Long-period ground motions in a laterally inhomogeneous large sedimentary basin: observations and model simulations of long-period surface waves in the northern Kanto Basin, Japan

Long-period ground motions in a laterally inhomogeneous large sedimentary basin: observations and model simulations of long-period surface waves in the northern Kanto Basin, Japan

Adjoint tomography of the crust and upper mantle structure beneath the Kanto region using broadband seismograms

Long-period seismic amplification in the Kanto Basin from the ambient seismic field

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