MASW For Geotechnical I nvestigation-The Way To Go

The multichannel analysis of surface waves (MASW) method is a seismic technique commonly used for the near-surface geotechnical characterization. MASW provides one of the most critically important geotechnical parameters-stiffness of ground materials. It gives this information in terms of seismic shear-wave velocity (Vs) distribution in both vertical and horizontal directions. From an elastic theory viewpoint, shear-wave velocity (Vs) is the most powerful indicator of material``s stiffness. MASW is an extremely "easy" geophysical approach in comparison to other approaches, both seismic and non-seismic. This is because it takes the seismic surface waves as signal that are always generated with an energy level a few orders of magnitude higher than that of the body waves. In fact, the history of the near-surface seismic body-wave (reflection) surveys indicates a significant amount of effort has been spent to suppress surface waves because of the dominant energy. Therefore, MASW always deals with the highest signal-to-noise ratio (SN) ever possible, making the field data acquisition procedure highly tolerant and then making subsequent data analysis steps simple and accurate. Although its predecessors such as SASW and CSW have much longer histories of development, MASW’s history is relatively short.it’s been a little over a decade since its first introduction in the early 2000s. Nonetheless, because of the adoption of multichannel techniques long used in the seismic oil exploration, MASW research and applications have been revealing much more details in surface wave phenomena than those previously known or speculated by the predecessors of the two-receiver approach. In consequence, this has dramatically improved the accuracy and applicability of the surface-wave method in general. Nowadays, MASW is being adopted as one of the routine NDT methods in civil engineering community. At the same time, it is still actively evolving by addressing new problems and challenges through theoretical studies and novel applications. The MASW method is briefly explained, and its typical applications are presented.