Abstract Seismology has come a long way in providing insights into Earth's internal structure and dynamics. Among many forward and inverse geophysical techniques developed, full waveform modelling, seismic tomography and receiver-based studies enabled detailed imaging of Earth's subsurface. The invention of ambient noise tomography within the last two decades revolutionized studies of Earth's subsurface based on the cross-correlation of the Earth's ambient noise. That method, in particular, enabled imaging of Earth structure in places where earthquakes or receivers do not exist. At the same time, progress in imaging the Earth's deepest shells has been impeded by the lack of geometric coverage of body waves due to uneven global distribution of seismic sources and receivers and the fact that the ambient noise studies cannot reach deeper than the uppermost Earth's shells, near its surface. In seeking the ways forward, global seismologists started experimenting with cross-correlating the part of the seismograms recorded many hours after the first arrivals of body-waves, the so-called earthquake coda. As in many science disciplines, initial work on this topic resulted in controversies but also led to new realisations and discoveries that all contributed to the rise of a new paradigm – the earthquake coda-correlation wavefield, which is the focus of this review paper. We do not attempt here to provide a review of ambient-noise correlation, although we use some familiar concepts to introduce coda-correlation. Our main goal is to review theoretical and observational work to date that resulted in a better understanding of the coda-correlation wavefield, both as a phenomenon and a powerful method. The features in global correlograms exist due to many cross-terms of reverberating body-waves, a principle fundamentally different from the reconstruction of surface waves in the ambient-noise correlograms. Once the coda-correlation wavefield is fully understood through theoretical developments, the method becomes a powerful way to study Earth's deep structure. Apart from providing a review of the most important results to date, we scrutinise the process of making global correlograms and analyse their characteristics while taking into consideration various aspects, such as the time after the earthquake, the source-receiver geometries, the level of seismicity and the type of earthquake mechanism. Furthermore, we provide practical examples on how to build correlograms and interpret correlogram features using programming language Python. Our review seeks to promote the topic of coda correlation among already experienced researchers as well as students who embark on this interesting research, which may play a central role in global and planetary seismology in the coming decades.

中文翻译：

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地球尾波相关波场：新范式的兴起和最新进展

摘要 地震学在深入了解地球内部结构和动力学方面取得了长足的进步。在开发的许多正向和反向地球物理技术中，全波形建模、地震层析成像和基于接收器的研究使地球地下的详细成像成为可能。过去二十年中环境噪声断层扫描的发明彻底改变了基于地球环境噪声互相关的地球地下研究。特别是这种方法能够在不存在地震或接收器的地方对地球结构进行成像。与此同时，地球成像方面的进展” 由于地震源和接收器的全球分布不均匀，以及环境噪声研究无法深入到地球表面附近的最上层壳层，因此体波的几何覆盖范围的缺乏阻碍了最深的壳层的研究。在寻找前进的道路时，全球地震学家开始尝试对在体波首次到达后数小时记录的地震图部分进行互相关，即所谓的地震尾波。与许多科学学科一样，关于该主题的初步工作引起了争议，但也导致了新的认识和发现，所有这些都促成了新范式的兴起——地震尾波相关波场，这是本评论论文的重点。我们不试图在这里提供环境噪声相关性的回顾，尽管我们使用了一些熟悉的概念来介绍 coda-correlation。我们的主要目标是回顾迄今为止的理论和观测工作，从而更好地理解尾波相关波场，无论是作为一种现象还是一种强大的方法。由于混响体波的许多交叉项，全局相关图中的特征存在，这一原理与环境噪声相关图中的表面波重建根本不同。一旦通过理论发展完全了解尾波相关波场，该方法将成为研究地球深层结构的有力方法。除了对迄今为止最重要的结果进行回顾之外，我们还仔细检查了制作全局相关图的过程并分析了它们的特征，同时考虑了各个方面，如震后时间、震源-接收器几何形状、地震活动水平和地震机制类型。此外，我们还提供了有关如何使用 Python 编程语言构建相关图和解释相关图特征的实际示例。我们的评论旨在在已经有经验的研究人员以及从事这项有趣研究的学生之间宣传尾波相关主题，这些研究可能在未来几十年在全球和行星地震学中发挥核心作用。