Surface waves as a cost-effective tool for enhancing the interpretation of shallow refraction seismic data
Abstract
Surface waves typically constitute the dominant component of the seismic record, thus yielding the highest signal-to-noise ratio. Their propagation velocities are closely linked to the shear-wave velocity of the medium.
In this study, we provide a review of the basics of surface wave analysis, focusing on Multichannel Analysis of Surface Waves (MASW). We illustrate this approach through four case studies representing common geophysical tasks.
By incorporating basic surface wave dispersion analysis into standard refraction surveys, we aim to reduce solution ambiguity and enhance knowledge without incurring additional costs.In Case Study 1, we address the topic of vertical geophone natural frequencies and compare data acquired simultaneously, concluding that even with 10 Hz geophones, surface wave dispersion analysis can yield satisfactory results.Case Study 2 demonstrates that MASW analysis can successfully supplement the standard travel-time tomography and help define geological interfaces.In Case Study 3, we demonstrate that obtaining P-wave and S-wave velocities from a single acquisition setup can aid in determining groundwater level.Case Study 4 showcases an example of joint passive and active MASW analysis, resulting in an extended shear wave velocity model. As our four case studies illustrate, when used appropriately and with an understanding of its limitations, MASW can serve as a powerful tool for subsurface investigation across various geological and geotechnical settings, significantly augmenting the knowledge derived from refraction data.