Abstract
Diffractions generated by the wavefield response of small-scale discontinuous geological bodies carry a wealth of information regarding complex geological structures, which can be used for high-resolution imaging. However, the weak amplitudes of diffractions make them vulnerable to strong reflections. Thus, separating diffractions from strong reflections is crucial in the high-resolution imaging of underground structures. The low-rank (LR) characteristics of seismic wavefields enable LR methods to be used for diffraction extraction. However, traditional low-rank algorithms tend to disrupt the dynamic characteristics of diffraction during the separation process, which is detrimental to the subsequent high-precision imaging of diffractions. To address these shortcomings of traditional methods, we propose a weighted multichannel singular spectrum analysis (MSSA) algorithm designed to preserve the dynamic characteristics of diffractions. This algorithm fully considers the distribution characteristics of diffractions and reflections energies within the singular spectrum and redefines the singular values using a weighted approach, ultimately achieving amplitude-preserving separation of diffracted waves. Through a combined qualitative and quantitative analysis of synthetic and field examples, we demonstrate the effectiveness of this method in separating diffractions and suppressing reflections with robustness and high stability. Compared with the traditional MSSA method, the proposed approach can provide better high-precision imaging results for small-scale geological structures.
Published Version
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