Surface-wave inversion using a direct search algorithm and its application to ambient vibration measurements

Passive recordings of seismic noise are increasingly used in earthquake engineering to measure in situ the shear-wave velocity profile at a given site. Ambient vibrations, which are assumed to be mainly composed of surface waves, can be used to determine the Rayleigh-wave dispersion curve, with the advantage of not requiring artificial sources. Due to the data uncertainties and the non-linearity of the problem itself, the solution of the dispersion-curve inversion is generally non-unique. Stochastic search methods such as the neighbourhood algorithm allow searches for minima of them is fit function by investigating the whole parameter space. Due to the limited number of parameters in surface-wave inversion, they constitute an attractive alternative to linearized methods. An efficient tool using the neighbourhood algorithm was developed to invert the one-dimensional V s profile from passive or active source experiments. As the number of generated models is usually high in stochastic techniques, special attention was paid to the optimization of the forward computations. Also, the possibility of inserting a priori information into the parametrization was introduced in the code. This new numerical tool was successfully tested on synthetic data, with and without a priori information. We also present an application to real-array data measured at a site in Brussels (Belgium), the geology of which consists of about 115 m of sand and clay layers overlying a Palaeozoic basement. On this site, active and passive source data proved to be complementary and the method allowed the retrieval of a V s profile consistent with borehole data available at the same location.

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

[2]  Amos Nur,et al.  Seismic velocities and Poisson's ratio of shallow unconsolidated sands , 2000 .

[3]  An analysis of the effects of site geology on the characteristics of near-field Rayleigh waves , 1988 .

[4]  B. Kennett,et al.  Non-linear waveform inversion for surface waves with a neighbourhood algorithm—application to multimode dispersion measurements , 2002 .

[5]  Michael W. Asten,et al.  Array estimators and the use of microseisms for reconnaissance of sedimentary basins. , 1984 .

[6]  Michael W. Asten,et al.  Array estimators and the use of microseisms for reconnaissance of sedimentary basins , 1984 .

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

[8]  Mrinal K. Sen,et al.  Nonlinear one-dimensional seismic waveform inversion using simulated annealing , 1991 .

[9]  Thomas Forbriger,et al.  Inversion of shallow-seismic wavefields: I. Wavefield transformation , 2003 .

[10]  堀家 正則,et al.  Inversion of phase velocity of long-period microtremors to the S-wave velocity structure down to the basement in urbanized areas , 1985 .

[11]  K. Aki,et al.  Quantitative Seismology, 2nd Ed. , 2002 .

[12]  W. Thomson,et al.  Transmission of Elastic Waves through a Stratified Solid Medium , 1950 .

[13]  M. Sambridge Geophysical inversion with a neighbourhood algorithm—I. Searching a parameter space , 1999 .

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

[15]  Salvatore Barba,et al.  Site response from ambient noise measurements: New perspectives from an array study in Central Italy , 1996, Bulletin of the Seismological Society of America.

[16]  Roel Snieder,et al.  Finding sets of acceptable solutions with a genetic algorithm with application to surface wave group dispersion in Europe , 1994 .

[17]  William H. Press,et al.  Numerical Recipes in C, 2nd Edition , 1992 .

[18]  Toshimi Satoh,et al.  Differences Between Site Characteristics Obtained From Microtremors, S-waves, P-waves, and Codas , 2001 .

[19]  M. Martini,et al.  Shallow velocity structure of Stromboli volcano, Italy, derived from small-aperture array measurements of Strombolian tremor , 1998, Bulletin of the Seismological Society of America.

[20]  R. Herrmann,et al.  Rayleigh waves in Quaternary alluvium from explosive sources: Determination of shear-wave velocity and Q structure , 1995 .

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

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

[23]  Thomas Forbriger,et al.  Inversion of shallow-seismic wavefields: II. Inferring subsurface properties from wavefield transforms , 2003 .

[24]  安芸 敬一 Space and time spectra of stationary stochastic waves, with special reference to microtremors , 1959 .

[25]  D. Jongmans,et al.  Use of microtremor measurement for assessing site effects in Northern Belgium – interpretation of the observed intensity during the MS = 5.0 June 11 1938 earthquake , 2004 .

[26]  Soheil Nazarian,et al.  In situ seismic testing with surface waves , 1989 .

[27]  N. A. Haskell The Dispersion of Surface Waves on Multilayered Media , 1953 .

[28]  Michael W. Asten,et al.  Resolving a velocity inversion at the geotechnical scale using the microtremor (passive seismic) survey method , 2004 .

[29]  Guust Nolet,et al.  Linearized Inversion of (Teleseismic) Data , 1981 .

[30]  Matthias Ohrnberger,et al.  Continuous automatic classification of seismic signals of volcanic origin at Mt. Merapi, Java, Indonesia , 2001 .

[31]  M. Asten Geological control on the three-component spectra of Rayleigh-wave microseisms , 1978 .

[32]  William H. Press,et al.  Numerical Recipes in Fortran 77: The Art of Scientific Computing 2nd Editionn - Volume 1 of Fortran Numerical Recipes , 1992 .

[33]  Frank Scherbaum,et al.  Love’s formula and H/V-ratio (ellipticity) of Rayleigh waves , 2004 .

[34]  J. W. Dunkin,et al.  Computation of modal solutions in layered, elastic media at high frequencies , 1965 .

[35]  R. T. Lacoss,et al.  ESTIMATION OF SEISMIC NOISE STRUCTURE USING ARRAYS , 1969 .