MASW-An Easy Seismic Method to Map Shear-Velocity (Vs) of the Ground

The multichannel analysis of surface waves (MASW) method is briefly described in its normal field procedure, data processing, and common applications to the engineering geology. It is a non-destructive seismic method utilizing the dispersion properties of Rayleigh-type surface w* aves to evaluate vertical and horizontal variation of shear-wave velocity (Vs) of ground materials down to a few tens of meters. Because of the strong nature of surface waves, therefore commonly treated as the strongest noise in the traditional seismic body-wave (e.g., reflection and refraction) surveys, the MASW data acquisition is almost always guaranteed to achieve a high signal-to-noise ratio (S/N), making the method easiest and simplest among all other seismic methods currently used. The high S/N also enables the subsequent data processing steps simple and reliable enough to be implemented by those who may not have extensive background knowledge or experience. General field and data-processing procedures are briefly described. A field example is also presented that evaluates the effectiveness of a compaction operation (Deep Dynamic Compaction) applied at a construction site.