Derivation of a Reference Shear-Wave Velocity Model from Empirical Site Amplification

Abstract The definition of a reference bedrock condition representative of a region of interest is of great significance in seismic-hazard assessment. It is highly beneficial when ground-motion prediction equations are referenced to a specific site condition, particularly in the case of site-specific seismic-hazard analyses. When known, the effect of any given site with respect to the reference can then be applied to the predicted ground motion. However, the choice of a reference velocity profile is not straightforward, mainly due to the high variability of the velocity structure in the shallower layers. A new method to define the regional reference rock profile is proposed. The method relates quarter-wavelength average velocity at a site to frequency-dependent amplification. A reference bedrock velocity profile can then be directly defined in relation to expected amplification characteristics over a number of sites. We compare 27 quarter-wavelength velocity profiles from seismic station locations in Switzerland with empirical amplification functions derived from spectral modeling. From this comparison, a set of frequency-dependent calibration relationships is established. Assuming that the reference profile is defined by a lack of any relative amplification, the quarter-wavelength velocity profile that corresponds to unitary spectral amplification can be extracted. The reference velocity profile can then be obtained through an inversion procedure and defines the reference for the ground-motion prediction equation (GMPE). The proposed reference velocity profile is compared with previous reference velocity profiles. A good agreement is found between the different methods. Additionally, an estimation of the transfer function for the Swiss reference rock condition is provided. This can be used to correct recorded or estimated spectral amplitudes for the local response of the reference site. Finally, it is shown that the coefficients from the aforementioned correlations can be used to estimate a generic amplification function at any site with a known quarter-wavelength velocity profile.

[1]  L. Y. Faust,et al.  Seismic Velocity as a Function of Depth and Geologic Time , 1951 .

[2]  L. Knopoff.  A matrix method for elastic wave problems , 1964 .

[3]  J. Capon.  High-resolution frequency-wavenumber spectrum analysis , 1969 .

[4]  J. Brune.  Tectonic stress and the spectra of seismic shear waves from earthquakes , 1970 .

[5]  R. Borcherdt.  Effects of local geology on ground motion near San Francisco Bay , 1970 .

[6]  M. Randall.  The spectral theory of seismic sources , 1973, Bulletin of the Seismological Society of America.

[7]  Roger D. Borcherdt,et al.  Effects of local geological conditions in the San Francisco Bay region on ground motions and the intensities of the 1906 earthquake , 1976, Bulletin of the Seismological Society of America.

[8]  Robin K. McGuire,et al.  The character of high-frequency strong ground motion , 1981 .

[9]  W. B. Joyner,et al.  The effect of Quaternary alluvium on strong ground motion in the Coyote Lake, California, earthquake of 1979 , 1981 .

[10]  D. Boore.  Stochastic simulation of high-frequency ground motions based on seismological models of the radiated spectra , 1983 .

[11]  John G. Anderson,et al.  A MODEL FOR THE SHAPE OF THE FOURIER AMPLITUDE SPECTRUM OF ACCELERATION AT HIGH FREQUENCIES , 1984 .

[12]  Frank L. Vernon,et al.  Multitaper spectral analysis of high-frequency seismograms , 1987 .

[13]  William H. Press,et al.  Numerical Recipes in FORTRAN - The Art of Scientific Computing, 2nd Edition , 1987 .

[14]  M. Campillo,et al.  The Mexico Earthquake of September 19, 1985—A Theoretical Investigation of Large- and Small-scale Amplification Effects in the Mexico City Valley , 1988 .

[15]  Seismic amplification—Mexico City , 1989 .

[16]  Frank Scherbaum,et al.  Combined inversion for the three-dimensional Q structure and source parameters using microearthquake spectra , 1990 .

[17]  Raúl R. Castro,et al.  Site response, attenuation and source spectra of S waves along the Guerrero, Mexico, subduction zone , 1990 .

[18]  Gail M. Atkinson,et al.  The shape of ground motion attenuation curves in southeastern Canada , 1992, Bulletin of the Seismological Society of America.

[19]  Keiiti Aki,et al.  Local site effects on weak and strong ground motion , 1993 .

[20]  Masayuki Takemura,et al.  Characteristics of long-period microtremors and their applicability in exploration of deep sedimentary layers , 1994, Bulletin of the Seismological Society of America.

[21]  J. Lees,et al.  Multiple-taper spectral analysis: a stand-alone C-subroutine , 1995 .

[22]  Jamison H. Steidl,et al.  What is a reference site? , 1996, Bulletin of the Seismological Society of America.

[23]  Donat Fäh,et al.  Seismic monitoring of explosions: a method to extract information on the isotropic component of the seismic source , 1997 .

[24]  Jamison H. Steidl,et al.  Site amplification in the San Fernando Valley, California: Variability of site-effect estimation using the S-wave, coda, and H/V methods , 1997, Bulletin of the Seismological Society of America.

[25]  David M. Boore,et al.  Site amplifications for generic rock sites , 1997, Bulletin of the Seismological Society of America.

[26]  Richard D. Miller,et al.  Multichannel analysis of surface waves , 1999 .

[27]  Andreas Rietbrock,et al.  P wave attenuation structure in the fault area of the 1995 Kobe earthquake , 2001 .

[28]  John Haines,et al.  The Choice of Reference Sites for Seismic Ground Amplification Analyses: Case Study at Parkway, New Zealand , 2003 .

[29]  T. L. Pratt,et al.  Amplification of Seismic Waves by the Seattle Basin, Washington State , 2003 .

[30]  D. Fäh,et al.  Inversion of local S-wave velocity structures from average H/V ratios, and their use for the estimation of site-effects , 2003 .

[31]  David M. Boore,et al.  Simulation of Ground Motion Using the Stochastic Method , 2003 .

[32]  W. Ellsworth,et al.  Apparent break in earthquake scaling due to path and site effects on deep borehole recordings , 2003 .

[33]  Stefan Wiemer,et al.  Probabilistic earthquake location in complex three‐dimensional velocity models: Application to Switzerland , 2003 .

[34]  D. Bindi,et al.  Comparison of Different Site Response Estimation Techniques Using Aftershocks of the 1999 Izmit Earthquake , 2004 .

[35]  Glenn J. Rix,et al.  Ground Motion Amplification of Soils in the Upper Mississippi Embayment , 2005 .

[36]  D. Bindi,et al.  Crustal Attenuation Characteristics in Northwestern Turkey in the Range from 1 to 10 Hz , 2006 .

[37]  Gail M. Atkinson,et al.  Earthquake Ground-Motion Prediction Equations for Eastern North America , 2006 .

[38]  Donat Fäh,et al.  Earthquakes in Switzerland and surrounding regions during 2006 , 2007 .

[39]  Donat Fäh,et al.  S‐wave velocity measurements applied to the seismic microzonation of Basel, Upper Rhine Graben , 2007 .

[40]  J. Bommer,et al.  Prediction of elastic displacement response spectra in Europe and the Middle East , 2007 .

[41]  Michael Krystek,et al.  A weighted total least-squares algorithm for fitting a straight line , 2007 .

[42]  Donat Fäh,et al.  Analysis of three-component ambient vibration array measurements , 2008 .

[43]  Comparison of Site-Effects Estimation Methods Using the Lefkas, Greece, 2003 Earthquake Aftershocks , 2008 .

[44]  Julian J. Bommer,et al.  The Acquisition of Source, Path, and Site Effects from Microearthquake Recordings Using Q Tomography: Application to the United Kingdom , 2008 .

[45]  Stéphane Drouet,et al.  Simultaneous Inversion of Source Spectra, Attenuation Parameters, and Site Responses: Application to the Data of the French Accelerometric Network , 2008 .

[46]  J. Douglas,et al.  Making the most of available site information for empirical ground-motion prediction , 2009 .

[47]  Benjamin Edwards,et al.  A Comparative Study on Attenuation and Source-Scaling Relations in the Kanto, Tokai, and Chubu Regions of Japan, Using Data from Hi-Net and KiK-Net , 2009 .

[48]  Donat Fäh,et al.  Estimating Rayleigh wave particle motion from three-component array analysis of ambient vibrations , 2010 .

[49]  Stéphane Drouet,et al.  vS30, κ, regional attenuation and Mw from accelerograms: application to magnitude 3–5 French earthquakes , 2010 .