Site-dependent attenuation relations of seismic motion parameters at depth using borehole data

1995 ◽  
Vol 85 (6) ◽  
pp. 1790-1804
Author(s):  
Yoshimitsu Fukushima ◽  
Jean-Christophe Gariel ◽  
Ryozo Tanaka
Keyword(s):  
Transfer Functions ◽  
Ground Surface ◽  
Response Spectra ◽  
Borehole Data ◽  
Ground Acceleration ◽  
Attenuation Relations ◽  
Attenuation Relationships ◽  
Geological Conditions ◽  
Velocity Response ◽  
Different Depths

Abstract Using more than 500 accelerometric records from three vertical arrays located in Japan, we performed a regression analysis in order to derive attenuation relationships at underground sites with depths ranging from 100 to 950 m. Analyses were conducted on both peak ground acceleration and pseudo-velocity response spectra. Because of a positive correlation between magnitude and distance, a two-step regression technique was employed. Results show that, compared with surface ground motion, peak accelerations at underground sites are lower by a factor ranging from 1.5 to 4 according to the depth. In the case of response spectra, differences between ground surface and underground spectra are dependent on geological conditions. For the three sites considered in the study, underground pseudo-velocity response spectra show amplitudes lower by a factor ranging from 1.5 to 10 according to the depth or the period considered. Ratios between the receiver responses obtained at different depths provided average transfer functions. Those were compared with transfer functions calculated by averaging ratios of observed response spectra between different depths. A good agreement between the two techniques was found. Finally, theoretical transfer functions were estimated using both one-dimensional SH and complete wave modeling. It was shown that the characteristics of the incident wave field can play an important role in the estimation of theoretical transfer functions.

Maximum Likelihood Estimation of Strong-Motion Attenuation Relationships

1991 ◽  
Vol 7 (2) ◽  
pp. 267-279 ◽  
Author(s):  
K. L. McLaughlin
Keyword(s):  
Maximum Likelihood ◽  
Strong Motion ◽  
Likelihood Estimation ◽  
Earthquake Ground Motion ◽  
Attenuation Relation ◽  
Ground Acceleration ◽  
Attenuation Relations ◽  
Attenuation Relationships ◽  
The Mean ◽  
Data Censoring

Strong-motion attenuation relations are commonly derived from earthquake ground motion collected on triggered recorders. Parametric attenuation relations are estimated from these data using standard least squares methods. The variance of ground acceleration is relatively large and for any given earthquake, there is a distance range for which only stations with larger than average amplitudes will trigger recording. Consequently observed accelerations at these distances are higher than the mean ground acceleration and a bias may be introduced into an attenuation relation regression by non-detection data censoring.

Horizontal-to-vertical spectral ratio and geological conditions: The case of Garner Valley Downhole Array in southern California

1996 ◽  
Vol 86 (2) ◽  
pp. 306-319 ◽  
Author(s):  
N. Theodulidis ◽  
P.-Y. Bard ◽  
R. Archuleta ◽  
M. Bouchon
Keyword(s):  
Southern California ◽  
Transfer Functions ◽  
High Sensitivity ◽  
Spectral Ratio ◽  
S Wave ◽  
Absolute Level ◽  
Data Set ◽  
Geological Conditions ◽  
Different Depths ◽  
Downhole Array

Abstract The aim of the present article is to further check the use of the horizontal-to-vertical (h/v) spectral ratio, which has been recently suggested as an indicator of site effects. The data set consists of 110, three-component, high sensitivity accelerograms, recorded at five different depths by the Garner Valley Downhole Array (GVDA), in southern California, with peak ground accelerations 0.0002 g ≦ ag ≦ 0.04 g, magnitudes 3.0 ≦ ML ≦ 4.6, and hypocentral distances 16 km ≦ R ≦ 107 km. First, the stability of the (h/v) spectral ratio is investigated by computing the mean for the whole data set in different depths. The (h/v) spectral ratio on the surface is compared with the surface-to-depth standard spectral ratio, with theoretical S-wave transfer functions derived from the vertical geotechnical profile, as well as with the (h/v) spectral ratio of synthetic accelerograms generated by the discrete wavenumber method. Both theoretical and experimental data show a good stability of the (h/v) spectral ratio shape, which is in good agreement with the local geological structure and is insensitive to the source location and mechanism. However, the absolute level of the (h/v) spectral ratio depends on the wave field and is different from the surface-to-depth spectral ratio. Consequently the (h/v) spectral ratio technique provides only partially the information that can be obtained from a downhole array. But surface-to-depth ratios may also be misleading because they combine effects at surface and at depth.

Large-Scale Two-Dimensional Nonlinear Analysis on Seismic Effect of Fuzhou Basin

2011 ◽  
Vol 90-93 ◽  
pp. 1426-1433 ◽  
Author(s):  
Dan Dan Jin ◽  
Guo Xing Chen ◽  
Fei Fan Dong
Keyword(s):  
Ground Motion ◽  
Large Scale ◽  
Ground Surface ◽  
Response Spectra ◽  
Seismic Effect ◽  
Two Dimensional ◽  
Acceleration Response ◽  
Ground Acceleration ◽  
One Dimensional ◽  
Amplification Effect

So far, nonlinear analyses on seismic effect of large-scale basin model have rarely been reported. Based on the explicit finite element method and 32 CPU parallel computing cluster platform of ABAQUS, a two-dimensional（2D） large-scale refined model for Fuzhou Basin is established using a nonlinear analytical method in the time domain. Both the peak ground acceleration (PGA) and acceleration response spectra of ground surface are emphatically analyzed. Meanwhile, the results by one-dimensional equivalent linearization method in frequency domain are added for the sake of contrast. The study results show that the PGA of ground surface will be obviously amplified when compared with the peak acceleration of bedrock ground motion; and the ground acceleration response spectra of Fuzhou Basin may appear a double-peak or multi-peak phenomenon. Moreover, the 2D large-scale model can reflect amplification effect of Fuzhou Basin soil to bedrock ground motion in particular periods; In addition, the acceleration responses of ground surface right above the bedrock valleys and crests appear larger than the other positions adjacent to them, these phenomenon are generally manifested as focusing effect and amplification effect, which are thought to be produced by the recently deposited soils in the basins as well as the special soil layer such as lens. In general, the PGA of ground surface obtained by 2D model present to be greater than that obtained by the one-dimensional model.

Updated PGA, PGV, and Spectral Acceleration Attenuation Relations for Iran

2012 ◽  
Vol 28 (1) ◽  
pp. 257-276 ◽  
Author(s):  
Hamid Saffari ◽  
Yasuko Kuwata ◽  
Shiro Takada ◽  
Abbas Mahdavian
Keyword(s):  
Response Spectra ◽  
Peak Ground Velocity ◽  
Model Parameters ◽  
Ground Acceleration ◽  
Attenuation Relations ◽  
Data Set ◽  
Site Class ◽  
Source Regions ◽  
Average Shear ◽  
Fault Mechanism

We have developed updated attenuation relations for peak ground acceleration (PGA), peak ground velocity (PGV), and acceleration response spectra with 5% damping on the basis of the data (78 earthquakes and 351 records) pertaining to strong ground motion in Iran. Moment magnitude, distance, fault mechanism, site class, and zone were the model parameters considered. A term for the saturation of the acceleration amplitude was also used in the model in order to improve the estimations in near-source regions. A nonlinear regression analysis was performed to obtain the coefficients. A comparison between the data set used in the current study for Iran and two next generation attenuation (NGA) models showed good correlation between our model and the Campbell-Bozorgnia NGA model. The model described is applicable for moment magnitudes from 5.0 to 7.3, distances from 15 to 135 km, and site classes with an average shear-wave velocity at a subsurface depth of 30 m (AVS30) of more than 175 m/s.

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