Removal of P- and S-Wave Decoupling Separation Artifacts in Forward Simulation Based on Adaptive Median Filtering

During the multicomponent seismic exploration, the P- and S-waves can be recorded, enabling us to obtain more information about the subsurface media. In the interpretation and processing of most multicomponent seismic data, the accurate separation of P- and S-waves in forward simulation and wavefield extrapolation is essential, such as elastic reverse time migration and elastic full-waveform inversion. We decouple the elastic wavefield based on the first-order velocity-stress elastic wave decoupling equation. However, this method produces obvious separation artifacts due to the nonzero spatial derivative of the elastic parameters at the geological interfaces, which can affect subsequent seismic processing and interpretation. To address this issue, an adaptive median filtering method is proposed to remove these artifacts. First, calculate the velocity change rate. Utilizing a designed threshold to filter velocity change rates, we determine the location of the interface where the artifacts appear. Then, the window calculation function based on the wavelength of seismic is used to obtain the median filtering window used for processing. Finally, it applies adaptive median filtering to remove the separated artifacts while preserving the valid information of the wavefields. This method preserves the effective wavefields and effectively removes separation artifacts. Through numerical simulations, it is verified that the adaptive median filtering method can effectively and completely remove the separation artifacts occurring at all interfaces.