Multichannel Analysis of Surface Waves (MASW)

Multi-Channel Analysis of Surface Waves (MASW): Advanced Subsurface Characterization

Multi-channel Analysis of Surface Waves (MASW) is a seismic technique that determines subsurface shear wave velocity profiles through measurement and analysis of propagating surface waves. Developed in the 1980s, this method has become a standard geophysical approach for shallow subsurface investigation, providing critical data on ground stiffness and mechanical properties essential for geotechnical engineering and site characterization.

MASW surveys measure how surface waves travel through the ground at different frequencies, with variations in wave velocity revealing the strength and stiffness of subsurface materials. From these measurements, we calculate shear wave velocities and maximum shear modulus values that directly inform foundation design, seismic site classification, and ground improvement strategies. The technique excels at mapping depth to bedrock, identifying voids or poorly consolidated zones, detecting lateral variations in ground conditions, and characterizing subsurface layering with exceptional detail.

Our MASW surveys deploy linear arrays of geophones that record surface waves generated by either active sources such as sledgehammers and weight drops, or passive sources including ambient noise from traffic and construction activities. Through advanced dispersion analysis and sophisticated inversion processing, we transform the recorded data into detailed velocity models that reveal how ground properties vary with depth. Applications span from assessing site conditions for construction projects and investigating geologic structures to monitoring subsurface changes over time and producing comprehensive seismic velocity profiles for engineering analysis.

The method offers compelling advantages as a completely non-destructive investigation technique requiring no drilling or trenching, making it cost-effective and efficient compared to intrusive methods. MASW is particularly powerful when integrated with complementary techniques such as seismic refraction or electrical resistivity tomography, providing multiple datasets that reduce uncertainty and deliver comprehensive subsurface understanding. Whether you need shallow profiling for foundation design, geotechnical characterization for seismic hazard assessment, or monitoring to track ground conditions, our MASW services deliver the quantitative mechanical property data essential for confident engineering decisions and optimized project outcomes.