Joint inversion of H/V ratios and dispersion curves from seismic noise: Estimating the S‐wave velocity of bedrock

[1] A joint inversion of phase velocity and H/V ratio curves, both obtained from seismic-noise recordings, permits the retrieval of the shear-wave velocity structure of local sedimentary cover. Our inversion scheme uses a genetic algorithm and considers the influence of higher modes on the data sets. Encouraged by the results published previously on joint inversion (Parolai et al., 2005) we went one step further. We found, using a synthetic data set, that the impedance contrast at the sediment-bedrock interface has a strong influence on the shape of the H/V ratio curve, which therefore allows the bedrock S-wave velocity to be well constrained in the joint-inversion procedure. Our observations were further confirmed using a real data set.

[1]  Stefano Parolai,et al.  Joint inversion of phase velocity dispersion and H/V ratio curves from seismic noise recordings using a genetic algorithm, considering higher modes , 2005 .

[2]  Hiroaki Yamanaka,et al.  Application of genetic algorithms to an inversion of surface-wave dispersion data , 1996, Bulletin of the Seismological Society of America.

[3]  Donat Fäh,et al.  A theoretical investigation of average H/V ratios , 2001 .

[4]  Frank Scherbaum,et al.  Determination of shallow shear wave velocity profiles in the Cologne, Germany area using ambient vibrations , 2003 .

[5]  David G. Harkrider,et al.  Surface waves in multilayered elastic media. I. Rayleigh and Love waves from buried sources in a multilayered elastic half-space , 1964 .

[6]  Kohji Tokimatsu,et al.  Effects of Multiple Modes on Rayleigh Wave Dispersion Characteristics , 1992 .

[7]  Frank Scherbaum,et al.  How good are shear wave velocity models obtained from inversion of ambient vibrations in the Lower Rhine Embayment (N.W. Germany) , 2004 .

[8]  Donat Fäh,et al.  Array measurements of S‐wave velocities from ambient vibrations , 2004 .

[9]  M. Ohori,et al.  A Comparison of ESAC and FK Methods of Estimating Phase Velocity Using Arbitrarily Shaped Microtremor Arrays , 2002 .

[10]  T. Ohmachi,et al.  Ground Motion Characteristics Estimated from Spectral Ratio between Horizontal and Verticcl Components of Mietremors. , 1997 .

[11]  Kohji Tokimatsu,et al.  S-Wave Velocity Profiling by Inversion of Microtremor H/V Spectrum , 2004 .