| This paper focus on the solution of a restricted condition——blend of wave field of P-wave and S-wave. According to comprehensive research analysis on wave field separation of different methods, such as resolution, effectively and scope of application,we try to find a useful method to separate the pure-mode and converted-wave signals. Characteristics of three-component geophone receiver decide the displacement vectors corresponding to various seismic waves produce projections on all geophone components, for instance, the vertical geophone can recevie shear wave, the horizontal geophone can receive compression wave. Converted-wave seismic data acquisition technique can help us obtain more information of elastic wave, but most of the conventional processing techniques we use can lead to the loss of plenty of converted-wave information. Converted- wave with low-velocity is considered to be a part of noise so as to gain worse result.Wave field characteristics of P- and S- wave determined their different processing flows, soseparating the overlap wave field appears to be particularly important.Based on the analysis of the movement law and propagative characteristic, techniques for wave field separation fall into two categories: ① kinematics feature dependent, removing noise by contrast of apparent velocity; ② dynamic feature dependent, polarization characteristic of motion of space rotating vector are reached. Primarily target of this paper are understandingτ-p transform filter method, separating by coordinate stretch of τ-p transform method, and the method of covariance matrix polarization filter. Relying solely on single feature is restricted to factors such as prior information and scope of application. The best method is gained after trials and analysis above method, a combination of kinematics feature and dynamic feature works better than relying solely on single feature. As a result, we propose a wave-field-separation scheme based on rotation of polarization in the τ-p domain. |
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