A Seismic Technique for near Surface Soil Investigation.

In order to investigate near surface soils in a non-invasive way, a seismic technique, so-called the multi-channel analysis of surface wave (MASW) method has been developed. In the method, an electro-mechanical shaker placing on the ground excites surface waves, or Rayleigh waves, propagating through the surface. The surface vibrations along a straight line are detected by a scanning laser Doppler vibrometer (LDV). Through signal processing technique, the shear wave velocity as a function of depth, soil profile, can be determined. The method could be applied to the studies of soil surface crusting, soil moisture variation, compaction effects, layering, and underground water flow. Several case studies will be presented.