A nearly discrete analytic method of wave-field simulation for elastic wave equations in the frequency domain

To improve the computing efficiency of numerically solving frequency-domain elastic wave equation, this paper introduces nearly analytic discrete (NAD) method for numerically discretizing the frequency-domain elastic wave equation to obtain a large-scale linear algebraic system. After the detailed analysis for sparse block structure and mathematical property of the corresponding coefficient matrix, the inexact rotated block triangular preconditioners are proposed to accelerate Krylov subspace iteration methods to solve the linear system and the numerical efficiency of such methods for elastic wave simulation is examined by numerical experiments. When comparing with the other two classical numerical schemes (ordinary finite difference method and staggered grid method) in wave-field simulation, numerical dispersion analysis and waveform comparison with analytic solution for various models, NAD method shows its advantages of increasing computing efficiency, suppressing numerical dispersion and the effectiveness of numerical simulation in complicated media.