LAUSR

Affected by the low-frequency seismic data missing and multiple parameters coupling, elastic full waveform inversion (EFWI) is easy to fall into local minima. This letter attempts to solve the local minima problem from two aspects: low-frequency seismic data reconstruction and wave mode decomposition. First, by introducing the envelope into sparse-constrained deconvolution (SCD), an envelope-based SCD (E-SCD) method is proposed to overcome the problem caused by the phase shift and side lobes. However, the resolution of the envelope is insufficient to identify overlapping seismic events, which are generated by velocity models rich in thin layers. Therefore, SCD and E-SCD are combined, and a dual deconvolution (D-D) method is proposed: SCD is used to improve the resolution of the original seismic data, and then, E-SCD is used to reconstruct high-precision reflection sequence. Convolve the reconstructed reflection sequence with the full-band source wavelet to obtain the full-band seismic data. Second, for the multiparameter coupling problem, we use wave mode decomposition to obtain separated P- and S-waves. Finally, a multiscale EFWI method based on D-D and wave mode decomposition is proposed. Numerical experiment results demonstrate the algorithm proposed in this letter.