Accurate 3D frequency-domain seismic wave modeling with the wavelength-adaptive 27-point finite-difference stencil: A tool for full-waveform inversion

Efficient frequency-domain full-waveform inversion (FWI) of long-offset node data can be performed with a few frequencies. The seismic response these frequencies computed compact finite-difference stencils on regular Cartesian grid direct or hybrid direct/iterative methods. Compactness, which is necessary to mitigate the fill-in induced by lower-upper factorization, implemented second-order stencils, whereas accuracy achieved building consistent mass matrix and compound stiffness optimal weights so that stencil covers eight cells surrounding central point, leading 27-point stencil. Classical approaches estimate constant jointly minimizing numerical dispersion in homogeneous media for several numbers points per wavelength ([Formula: see text]). Then, impedance built using at each point covering heterogeneous subsurface model, nonuniform wavefield accuracy. Instead, we [Formula: text]-dependent once all separately value text] range found FWI applications. build without computational overhead selecting corresponding local text], hence wavelength-adaptive This separate approach adaptive makes uniform. We benchmark wavefields, are 3D large-scale models sparse multifrontal solver nonadaptive/adaptive against analytical solutions when available highly accurate discretization-free convergent Born series method. Each reveals higher relative nonadaptive one. In presence sharp contrasts, also more than classical finite-different time-domain staggered-grid relevance finally illustrated case study 3.5–13 Hz frequency band.