ABSTRACT Full‐waveform inversion (FWI) is a powerful technique for constructing high‐resolution subsurface models, which are essential for hydrocarbon exploration, field development and the interpretation of deep Earth structures. However, seismic signals are often subject to amplitude decay and phase distortion due to intrinsic attenuation, which can significantly degrade inversion accuracy, particularly when attenuation and the associated velocity dispersion effects are not accounted for. To address these challenges, there is an increasing demand for multiparameter viscoelastic FWI methods that can simultaneously invert for both velocity and attenuation models. In this study, we present a novel P‐ and S‐wave separation approach based on the nearly constant‐ Q viscoelastic model. The proposed method incorporates a gradient preconditioning technique designed to improve inversion accuracy by mitigating the interference between the gradients of P‐ and S‐wave velocities—a persistent issue in multiparameter inversions, particularly in the presence of anomalous geological bodies. We derive the necessary formulations for wavefield separation and gradient preprocessing using the pseudo‐Hessian operator and validate the methodology through numerical simulations based on the Marmousi‐2 model and real ocean bottom node (OBN) data. The results demonstrate that the proposed method significantly enhances inversion accuracy, particularly in geologically complex regions. This approach offers a promising solution for achieving more precise subsurface imaging in viscoelastic media.
Han et al. (Sat,) studied this question.