Mixed-grid finite-difference frequency-domain viscoacoustic modeling in 2D TTI anisotropic media

International audienceWe present a 2D finite-difference frequency-domain method for modeling viscoacoustic wave propagation in TTI media. The numerical method relies on a parsimonious staggered-grid method implemented in the frequency domain. Differential operators are discretized along different rotated coordinate systems (the classic Cartesian one and a 45° rotated one) with second-order accurate staggered-grid stencils. The resulting discrete operators are combined linearly to mitigate numerical anisotropy. An anti-lumped mass strategy is applied to mitigate numerical dispersion. A dispersion analysis for infinite homogeneous media suggests a discretization rule of 5 grid points per wavelength. Numerical tests confirm the accuracy of the stencil