Improvement of coda phase detectability and reconstruction of global seismic data using frequency-wavenumber methods
Improvement of coda phase detectability and reconstruction of global seismic data using frequency-wavenumber methods
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DOI：
10.1093/gji/ggx477
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发表时间：
2018-02
影响因子：
2.8
通讯作者：
S. Schneider;C. Thomas;R. Dokht;Y. Gu;Yunfeng Chen
中科院分区：
文献类型：
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作者：
S. Schneider;C. Thomas;R. Dokht;Y. Gu;Yunfeng Chen
由于地震源和接收器分布不均匀，我们将微弱信号与干扰相位隔离并重建丢失数据的能力对于提高地震成像技术的分辨率至关重要。在本研究中，我们引入了一种使用“凸集投影”(POCS) 算法的改进频率波数 (fk) 域方法。 POCS利用fk域中相位到达的主要能量的稀疏性，能够有效检测和重建弱地震信号。此外，我们的算法利用二维傅立叶变换来执行噪声去除、插值和弱相位提取。为了提高重建数据的方向分辨率，我们引入了带阻二维傅里叶滤波器来消除 fk 域中不需要的干扰相位的能量，这显着提高了感兴趣信号的鲁棒性。使用来自坦桑尼亚阵列的 PP 前体的模拟和实际宽带记录清楚地证明了该方法的有效性和优点。如果使用得当，该方法可以显着提高弱地壳和地幔震相的分辨率。
Due to uneven earthquake source and receiver distributions, our abilities to isolate weak signals from interfering phases and reconstruct missing data are fundamental to improving the resolution of seismic imaging techniques. In this study, we introduce a modified frequency- wavenumber (fk) domain based approach using a 'Projection Onto Convex Sets' (POCS) algorithm. POCS takes advantage of the sparsity of the dominating energies of phase arrivals in the fk domain, which enables an effective detection and reconstruction of the weak seismic signals. Moreover, our algorithm utilizes the 2-D Fourier transform to perform noise removal, interpolation and weak-phase extraction. To improve the directional resolution of the reconstructed data, we introduce a band-stop 2-D Fourier filter to remove the energy of unwanted, interfering phases in the fk domain, which significantly increases the robustness of the signal of interest. The effectiveness and benefits of this method are clearly demonstrated using both simulated and actual broadband recordings of PP precursors from an array located in Tanzania. When used properly, this method could significantly enhance the resolution of weak crust and mantle seismic phases.