Multi-Channel Analysis of Surface Waves (MASW)
The multi-channel analysis of surface waves (MASW) method is a seismic technique used for evaluating the elastic condition (stiffness) of the ground for geotechnical engineering purposes. MASW is capable of accurately mapping the soil/bedrock interface through analysis of shear wave velocities. The MASW procedure first measures seismic surface waves generated from various types of seismic sources; such as sledge hammer, weight drop or traffic noise. The procedure then analyzes the propagation velocities of those surface waves, and then finally deduces shear-wave velocity (Vs) variations below the surveyed area that are most responsible for the analyzed propagation velocity pattern of surface waves.
Shear-wave velocity (Vs) is one of the elastic constants and closely related to Young’s modulus. Under most circumstances, Vs is a direct indicator of the ground strength (stiffness) and therefore commonly can be used to derive load-bearing capacity and material type.