scholarly journals Modeling of a shallow S-wave velocity structure for evaluation of site amplification spectrum: Osaka Bay areas

2005 ◽  
Vol 5 (1) ◽  
pp. 1-16 ◽  
Author(s):  
Ikuo Cho ◽  
Boming Zhao ◽  
Takao Kagawa
Keyword(s):  
Wave Velocity ◽  
Velocity Structure ◽  
Site Amplification ◽  
S Wave ◽  
Osaka Bay ◽  
Amplification Spectrum

scholarly journals Estimation of S-Wave Velocity Profiles at Lima City, Peru Using Microtremor Arrays

2014 ◽  
Vol 9 (6) ◽  
pp. 931-938 ◽  
Author(s):  
Selene Quispe ◽  
◽  
Kosuke Chimoto ◽  
Hiroaki Yamanaka ◽  
Hernando Tavera ◽  
...  
Keyword(s):  
Wave Velocity ◽  
Velocity Structure ◽  
Site Effect ◽  
Site Amplification ◽  
Velocity Profiles ◽  
S Wave ◽  
Phase Velocity Dispersion ◽  
Seismic Recording ◽  
Phase Velocity Dispersion Curve ◽  
Alluvial Material

Microtremor exploration was performed around seismic recording stations at five sites in Lima city, Peru in order to know the site amplification at these sites. The Spatial Autocorrelation (SPAC) method was applied to determine the observed phase velocity dispersion curve, which was subsequently inverted in order to estimate the 1-D S-wave velocity structure. From these results, the theoretical amplification factor was calculated to evaluate the site effect at each site. S-wave velocity profiles at alluvial gravel sites have S-wave velocities ranging from ∼500 to ∼1500 m/s which gradually increase with depth, while Vs profiles at sites located on fine alluvial material such as sand and silt have Swave velocities that vary between ∼200 and ∼500 m/s. The site responses of all Vs profiles show relatively high amplification levels at frequencies larger than 3 Hz. The average transfer function was calculated to make a comparison with values within the existing amplification map of Lima city. These calculations agreed with the proposed site amplification ranges.

scholarly journals Rapid assessment of S-wave profiles from the inversion of multichannel

1998 ◽  
Vol 41 (1) ◽  
Author(s):  
G. A. Tselentis ◽  
G. Delis
Keyword(s):  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Velocity Structure ◽  
Rapid Assessment ◽  
Detailed Knowledge ◽  
S Wave ◽  
Surface Wave Dispersion ◽  
Wave Profiles ◽  
Shear Wave Velocity Structure

The importance of detailed knowledge of the shear-wave velocity structure of the upper geological layers was recently stressed in strong motion studies. In this work we describe an algorithm which we have developed to infer the 1D shear wave velocity structure from the inversion of multichannel surface wave dispersion data (ground-roll). Phase velocities are derived from wavenumber-frequency stacks while the inversion process is speeded up by the use of Householder transformations. Using synthetic and experimental data, we examined the applicability of the technique in deducing S-wave profiles. The comparison of the obtained results with those derived from cross-hole measurements and synthesized wave fields proved the reliability of the technique for the rapid assessment of shear wave profiles during microzonation investigations.

Estimation of site amplification and S-wave velocity profiles in metropolitan Manila, the Philippines, from earthquake ground motion records

2011 ◽  
Vol 42 (1) ◽  
pp. 69-79 ◽  
Author(s):  
Hiroaki Yamanaka ◽  
Kaoru Ohtawara ◽  
Rhommel Grutas ◽  
Robert B. Tiglao ◽  
Melchor Lasala ◽  
...  
Keyword(s):  
Ground Motion ◽  
Wave Velocity ◽  
Site Amplification ◽  
Velocity Profiles ◽  
The Philippines ◽  
Earthquake Ground Motion ◽  
S Wave ◽  
Ground Motion Records

Microtremor exploration for shallow S-wave velocity structure in Bandung Basin, Indonesia

2017 ◽  
Vol 48 (4) ◽  
pp. 401-412 ◽  
Author(s):  
Andi Muhamad Pramatadie ◽  
Hiroaki Yamanaka ◽  
Kosuke Chimoto ◽  
Kazuki Koketsu ◽  
Minoru Sakaue ◽  
...  
Keyword(s):  
Wave Velocity ◽  
Velocity Structure ◽  
S Wave

Tuning S-Wave Velocity Structure of Deep Sedimentary Layers in the Shimousa Region of the Kanto Basin, Japan, Using Autocorrelation of Strong-Motion Records

2020 ◽  
Vol 110 (6) ◽  
pp. 2882-2891
Author(s):  
Kosuke Chimoto ◽  
Hiroaki Yamanaka
Keyword(s):  
Wave Velocity ◽  
Velocity Structure ◽  
Strong Motion ◽  
S Wave ◽  
Reflected Waves ◽  
Arrival Times ◽  
Strong Motion Records ◽  
Kanto Basin ◽  
Determination Of Parameters

ABSTRACT The autocorrelation of ambient noise is used to capture reflected waves for crustal and sedimentary structures. We applied autocorrelation to strong-motion records to capture the reflected waves from sedimentary layers and used them for tuning the S-wave velocity structure of these layers. Because a sedimentary-layered structure is complicated and generates many reflected waves, it is important to identify the boundary layer from which the waves reflected. We used spectral whitening during autocorrelation analysis to capture the reflected waves from the seismic bedrock with an appropriate smoothing band, which controls the wave arrival from the desired layer boundary. The effect of whitening was confirmed by the undulation frequency observed in the transfer function of the sedimentary layers. After careful determination of parameters for spectral whitening, we applied data processing to the strong-motion records observed at the stations in the Shimousa region of the Kanto Basin, Japan, to estimate the arrival times of the reflected waves. The arrival times of the reflected waves were found to be fast in the northern part of the Shimousa region and slow in the western and southern parts. These arrival times are consistent with those obtained using existing models. Because we observed a slight difference in the arrival times, the autocorrelation function at each station was used for tuning the S-wave velocity structure model of the sedimentary layers using the inversion technique. The tuned models perfectly match the autocorrelation functions in terms of the arrival time of the reflected waves from the seismic bedrock.

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