Abstract：With the development of vertical seismic profile (VSP),high fidelity wave separation becomes one of key issues in VSP data processing and applications.According to underdetermined blind signal separation theory,a method based on sparse representation is presented in this paper.It depends on polarization characteristics of VSP wave field and sparsity of multi-component data in the time-frequency domain.The method has two stages:first,transforming seismic data from the time domain into the time-frequency domain and estimating polarization matrix; second,separating pure wave in the time-frequency domain and transforming it back into the time domain.It is difficult to acquire pure wave if it is not sparse enough in the time-frequency domain.In this paper,a modified shortest path decomposition method is presented,which can solve the problem of pure wave overlap in the local time-frequency area to a certain degree.Synthetic and real data examples show that with the proposed method every pure wave is accurately separated and amplitudes are well maintained without flaws such as wave mixing,aliasing,and boundary problem compared with conventional methods.
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