Analysis of effects of active sources on observed phase velocity based on the thin layer method

Estimation of 2D Shear Wave Velocity Profile of Soil Layers Using Surface Wave Seismic Tests

“…Theoretical dispersion curve can be constructed by thin layer stiffness matrix method 6) . The soil layers are divided into some thin layers, firstly.…”

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

“…2, the natural modes of the planar P-SV waves can be obtained by solving an eigenvalue problem (Chai et al, 2011;Ganji et al, 1998;Kausel, 1999;Kausel and Peek, 1982;Kausel and Roësset, 1981). Then, the discrete analytical expressions of the Green's functions in cylindrical coordinates can be obtained (See Appendix A).…”

“…It is well known that R-waves at different frequencies travel at the same phase velocity c R in homogeneous elastic half spaces (Chai et al, 2011). The spectra are then related to the penetration depth by using the relationship λ R = c R /f.…”

“…Thus, for cavities beyond that depth, detection by the body waves is the preferred choice. The surface-wave field far from the source is dominated by R-waves due to the slowest geometric attenuation among P-, S-and R-waves (Chai et al, 2011;Graff, 1975). 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.…”

“…R-waves induced by a point or a disk-like surface source approximately propagate in cylindrical wavefronts and approach to those in planar wavefronts in the field where the offset is large (Chai et al, 2011). When a cavity is located in the far field and it is relatively long in the transverse direction, the problem may be approximately simplified as the plane strain one.…”