Rayleigh Wave Inversion

Correctly sampled surface waves can help improve noise attenuation

The coherent noise in seismic data consists mainly of surface waves propagating in the near surface from sources to receivers. The type and properties of surface waves depends on the elastic properties of the shallow subsurface, whose lateral variations and heterogeneities strongly affect surface-wave behavior. In conventional land seismic technology, surface waves are considered coherent noise to be attenuated as early as possible in the processing.

On the other hand, when surface waves are properly sampled, they can be analyzed to evaluate the 3D distribution of surface-wave properties. The inversion of surface-wave properties contributes to the building of a near-surface model to be used in data processing for velocity modeling, perturbation corrections, and other applications.

The identification of surface-wave properties allows the use of tailored filters and an optimized parameterization for better noise attenuation and signal protection.

The surface-wave analysis and inversion, common in the engineering geophysics applications, will be part of the Land workflow. With low-frequency sources and receivers and an adequate spatial sampling, the investigated depth can reach hundreds of meters, exploiting all synergies with refraction-based techniques.