Effects of obstacles on Rayleigh wave dispersion obtained from the SASW test

Near-offset effects on Rayleigh-wave dispersion measurements: Physical modeling

“…Surface-wave dispersion measurements may then be corrupted by near-field effects, which are indeed considered to be the cause of underestimation, at low frequencies, of measured velocity vs. actual velocity (Yoon andRix, 2004, 2006;Strobbia and Foti, 2006). Full-wave numerical and analytical simulations (Gucunski et al, 1996;O'Neill, 2003) both reveal this underestimation, which has also been encountered in the field (Foti, 2000).…”

Spectral analysis of ambient ground-motion—Noise reduction techniques and a methodology for mapping horizontal inhomogeneity

“…Different case studies and numerical simulations have shown that embedded inhomogeneities of seismic properties can have significant effects on the seismic surface response of a medium (Campman et al, 2004;Gucunski et al, 1996;Phillips et al, 2004;Rechtien and Stewart, 1975). Consequently, the quasi-stationary, ambient seismic wavefield at the Earth's surface must be affected by the seismic properties of the subsurface.…”

Some theoretical and numerical observations on scattering of Rayleigh waves in media containing shallow rectangular cavities

“…When shallow cavities (at depths less than 50 m) are located in the far field where the ratio of the offset to the wavelength is relatively large and the activated R-waves can penetrate to the depth of interest, scattering of R-waves will play a major role in the scattering wave field. Some detection techniques based on the strong energy of the scattered R-waves have been studied using numerical analyses, model experiments and in-situ experiments (Ganji et al, 1997;Gelis et al, 2005;Grandjean and Leparoux, 2004;Gucunski et al, 1996;Nagueria et al, 1994;Riyanti, 2005;Tallavó et al, 2009;Wijk, 2003;Xia et al, 2007). Since the scattered waves can be obscured by the direct R-waves, some methods and technologies are used to diminish or suppress the direct R-waves (Campman, 2005;Campman et al, 2005;Pant and Greenhalch, 1989;Xia et al, 2007).…”