Effect of Lateral Heterogeneity in the Soil Column on Shear-wave Velocity Estimation by Rayleigh-wave Inversion

We conducted elastic wavefield modeling of shot gathers using soil-column models with vertical and lateral velocity variations to study the dispersive behavior of Rayleigh waves and the effect of lateral heterogeneity on the accuracy of Rayleigh-wave inversion for shear-wave velocity estimation. We also conducted a field experiment over an alluvial valley with soil column that thins out in the direction orthogonal to the valley axis. From the model and field experiments, we found that the dispersion characteristics of Rayleigh waves is greatly influenced by the geometry of and lateral heterogeneities within the soil column. Nevertheless, estimation of shear-wave velocities within a soil column with lateral heterogeneity by Rayleigh-wave inversion is sufficiently robust and accurate for geotechnical applications.