Distinct lateral variations of upper mantle anisotropy beneath eastern China revealed by shear‐wave splitting
Distinct lateral variations of upper mantle anisotropy beneath eastern China revealed by shear‐wave splitting
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DOI：
10.1002/ggge.20126
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发表时间：
2013-06
期刊：
影响因子：
3.7
通讯作者：
Hui Huang;Mingjie Xu;Liangshu Wang;Zhouchuan Huang;Pan Wang;N. Mi;Hua Li;Dayong Yu
中科院分区：
文献类型：
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作者：
Hui Huang;Mingjie Xu;Liangshu Wang;Zhouchuan Huang;Pan Wang;N. Mi;Hua Li;Dayong Yu
部署了由28个临时台站组成的密集地震台阵，以研究中国东部地壳和上地幔变形。我们通过分析在莫霍面不连续面（称为PmS相）和核幔边界（即，核心阶段）。核相分裂参数在大多数台站得到，而PmS相分裂参数仅在少数台站得到。用岩心相位分析的快极化方向在中国东部不同构造块体中存在明显的横向变化。地幔和地壳中的延迟时间分别较大（~1 s）和平均小于0.3s。菲涅耳带分析揭示了华南块体东部两个亚块体（东南造山带和扬子区）之间岩石圈各向异性的横向差异。而在华北东南部，相对较深层的各向异性对分裂观测有贡献。
A dense seismic array consisting of 28 temporary stations was deployed to study the crustal and upper‐mantle deformations beneath eastern China. We measured the splitting parameters in the crust and mantle by analyzing P‐to‐S phases converted at the Moho discontinuity (called PmS phases) and the core‐mantle boundary (i.e., core phases), respectively. The splitting parameters of core phases are retrieved at most stations while that of the PmS phases are retrieved at only a few stations. Distinct lateral variations of the fast polarization directions analyzed with the core phases are found in different tectonic blocks in eastern China. The delay times in the mantle and crust are moderately large (~1 s) and averagely smaller than 0.3 s, respectively. By the Fresnel‐zone analysis, the laterally variant lithospheric anisotropy is revealed between the two sub‐blocks (Southeast China Orogenic Belt and Yangtze Craton) of the eastern South China Block. In contrast, in the southeastern North China Craton, the anisotropy in a relatively deep layer contributes to the splitting observations.