Abstract
Elastic least-squares reverse-time migration (ELSRTM) is an advanced technique for imaging complex geologic structures using multicomponent seismic data. However, conventional ELSRTM methods fail to account for intrinsic earth attenuation or the coupling effects between elastic wavefields. To overcome these limitations, we validate the newly derived decoupled viscoelastic wave equations and develop an innovative decoupled ELSRTM method specifically designed for viscoelastic media. Our approach involves obtaining pure viscous P and S waves by solving the newly derived decoupled forward and adjoint viscoelastic wave equation. We use these pure viscous waves to construct the gradients for PP- and PS-wave modes, which are used to update the P- and S-wave reflectivity images iteratively. In addition, we develop a local wavefield storage scheme to avoid repeated simulations of the background wavefield during migration and demigration. Numerical examples demonstrate that our migration method effectively mitigates attenuation effects, reduces crosstalk artifacts, and significantly conserves computational resources compared with conventional ELSRTM methods.
Paper Information
Ye, Z., J. Huang, and J. D. Yang, 2025. Least-squares reverse-time migration based on decoupled viscoelastic wave equation using an efficient local wavefield storage scheme. Geophysics, 90(4), S129–S143, DOI: 10.1190/geo2024-0521.1
