Numerical Experiments on Acoustic Full-Wave Inversion in Frequency Domain

摘要

We have developed a full-wave inversion method based on the acoustic wave-equation in frequency-do-main (FFWI) - Although this method is mathematically equivalent to the full-wave inversion in time-domain (TFWI), both the forward modeling and the model updating are performed in the frequency-domain.The results of numerical studies show that the inversion using sparsely sampled frequency components can reconstruct accurate images. And accurate images can be obtained by the inversion using the only one frequency component if the difference between the phase spectra of the initial and the true models is small enough from a sufficiently low frequency to the frequency used for the inversion.In concluding, we propose the most optimum selection of frequency components for FFWI inversion. One should start an inversion procedure with an sufficiently low frequency component for the purpose of inversion stability. Finally, a high resolution result is obtained by adding several higher frequency components which are objectively selected by use of the maximum phase residual error as an indicator.Considering the computational cost of FFWI is almost proportional to the number of frequency components, one can easily reduce the computational cost by using limited number of frequency components.