Abstract

Besides groundwater, engineering, and environmental studies, the near-surface shear wave (S-wave) velocity is of fundamental interest for static correction application during S-wave reflection data processing. The frequency dependent characteristics of Rayleigh-wave, which is considered to be noise during body-wave prospecting, can be utilized to infer near surface elastic properties. In the early 1980s, a wave propagation method to generate the near surface VS profile, called spectral analysis of surface waves (SASW) was introduced. SASW uses the spectral analysis of ground roll generated by an impulsive source and recorded by a pair of receivers. Low signal-noise ratio recording of ground roll data and high degree of change in near surface elastic properties necessitate multi-channel analysis of surface waves (MASW). Multi-channel surface waves can be extracted from conventional seismic records, although dedicated techniques are available for continuous acquisition of noise-free, broad-band, multi-channel surface wave data. The multi-channel analysis includes the construction of dispersion curves from observed Rayleigh- waves, and inversion of VS profile from the calculated dispersion curves.