Estimation of shear wave velocity in shallow marine sediments

A method for estimating shear wave velocity in shallow marine sediments from the dispersive characteristics of seismic interface waves traveling at the water/sediment boundary is presented. Interface waves are recorded using an array of geophones placed on the seafloor, and the shear wave velocity is estimated by a nonlinear least-square inversion algorithm, with smoothing constraints to avoid numerical instability. A detailed description of the algorithm is given, particularly emphasizing the capabilities and limitations of the method. The inversion scheme has been tested at selected sites to compare its estimates with existing direct measurements of shear speed, and it has been proven reliable and accurate. The proposed scheme is able to predict shear speed to a typical depth of 15-40 meters within the sediment, which generally exceeds the depth for which direct measurements are available. >

[1]  A. Dziewoński,et al.  A technique for the analysis of transient seismic signals , 1969 .

[2]  James F. Lynch,et al.  Perturbative inversion methods for obtaining bottom geoacoustic parameters in shallow water , 1987 .

[3]  Ole F. Hastrup,et al.  Acoustic bottom reflectivity , 1986 .

[4]  Determination of shear velocity profiles by inversion of interface wave data , 1991 .

[5]  Surface Wave Inversion for Shear Wave Velocity , 1991 .

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

[7]  J. Scales,et al.  Regularisation of nonlinear inverse problems: imaging the near-surface weathering layer , 1990 .

[8]  A Fast Simulated Annealing Algorithm for the Inversion of Marine Sediment Seismo-Acoustic Parameters , 1991 .

[9]  E. Hamilton Geoacoustic modeling of the sea floor , 1980 .

[10]  Dieter Rauch Seismic Interface Waves in Coastal Waters: A Review , 1980 .

[11]  J. Baumeister Stable solution of inverse problems , 1987 .

[12]  G. Backus,et al.  The Resolving Power of Gross Earth Data , 1968 .

[13]  Maurice Ewing,et al.  Numerical inversion of seismic surface wave dispersion data and crust‐mantle structure in the New York‐Pennsylvania area , 1962 .

[14]  Gene H. Golub,et al.  Matrix computations , 1983 .

[15]  G. Frisk Inverse methods in ocean bottom acoustics , 1987 .

[16]  Loyd D. Hampton,et al.  Acoustic Properties of Sediments , 1964 .

[17]  M. Richardson,et al.  Shear Wave Velocity Gradients in Near-Surface Marine Sediment , 1991 .

[18]  Robert D. Stoll,et al.  Field experiments to study seafloor seismoacoustic response , 1990 .

[19]  M. Richardson,et al.  Sediment Shear Waves: A Comparison of In Situ and Laboratory Measurements , 1991 .