Heterogeneity of Seismic Wave Velocity in Earth's Mantle
Heterogeneity of Seismic Wave Velocity in Earth's Mantle
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DOI：
10.1146/annurev-earth-082119-065909
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发表时间：
2020-05
影响因子：
14.9
通讯作者：
J. Ritsema;V. Lekić
中科院分区：
文献类型：
--
作者：
J. Ritsema;V. Lekić
地震学为深部地幔的结构和动力学提供了重要的约束。过去二十年的计算和方法论进步改进了地幔的层析成像，揭示了从核心-地幔边界区域上升的羽流和沉入下地幔的海洋岩石圈板片的精细尺度结构。我们讨论全局层析成像的建模方面，包括理论近似、数据选择以及模型保真度和分辨率。通过频谱分析、主成分分析和聚类分析，我们强调了地震非均质性的稳健模式，这些模式告诉我们地幔中的流动、板块运动的历史以及潜在的成分不同的储层。最后，我们强调，对大量地震波形的数据挖掘以及来自分布式声学传感、自主水听器、海底地震仪和基于相关技术的新数据将促进下一代全球密度、地震速度和衰减模型的发展。 ▪ 地震层析成像揭示了地幔中地震速度不均匀性在100 公里至1,000 公里尺度上的变化。 ▪ 断层扫描图像是地幔循环和演化最重要的地球物理约束。
Seismology provides important constraints on the structure and dynamics of the deep mantle. Computational and methodological advances in the past two decades improved tomographic imaging of the mantle and revealed the fine-scale structure of plumes ascending from the core-mantle boundary region and slabs of oceanic lithosphere sinking into the lower mantle. We discuss the modeling aspects of global tomography including theoretical approximations, data selection, and model fidelity and resolution. Using spectral, principal component, and cluster analyses, we highlight the robust patterns of seismic heterogeneity, which inform us of flow in the mantle, the history of plate motions, and potential compositionally distinct reservoirs. In closing, we emphasize that data mining of vast collections of seismic waveforms and new data from distributed acoustic sensing, autonomous hydrophones, ocean-bottom seismometers, and correlation-based techniques will boost the development of the next generation of global models of density, seismic velocity, and attenuation. ▪ Seismic tomography reveals the 100-km to 1,000-km scale variation of seismic velocity heterogeneity in the mantle. ▪ Tomographic images are the most important geophysical constraints on mantle circulation and evolution.