Multimodal Ground-Roll Attenuation in Vertical and Radial Seismic Components

Multimodal Rayleigh waves are commonly recorded in three-component (3C) seismic data. They are a type of coherent noise, known as ground roll, in seismic surveys. In this paper we focus on the attenuation of ground roll and extend the model-based attenuation method proposed by Bai and Yilmaz (2018) to the radial component of 3C seismic data. Given a viscoelastic layered half-space model, we simulate surface-wave propagation and calculate the vertical and radial components of ground roll. For each seismic component, we independently estimate optimal models to minimize the misfit of dispersion spectra obtained from seismic and synthetic data. Once an optimal model is obtained, the synthetic data from the optimal model is adaptively subtracted from its corresponding seismic component. Since the characteristics of ground roll in the vertical and radial components are very different, the method provides a flexible way to remove ground roll for each component. Preliminary results for a 3D-3C field data indicate that ground roll is gradually eliminated during the iterations of surface-wave inversions and adaptive subtractions and, finally, most ground roll can be removed from the vertical and radial components.