Slab morphology and deformation beneath Izu-Bonin
Slab morphology and deformation beneath Izu-Bonin
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DOI：
10.1038/s41467-019-13133-1
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发表时间：
2019-03-21
影响因子：
16.6
通讯作者：
Guo, Hao
中科院分区：
文献类型：
--
作者：
Zhang, Haijiang;Wang, Fan;Guo, Hao
地震层析成像对俯冲板片的形态、变形和（间接）流变学提供了独特的约束。我们使用远震双差 P 波断层扫描以前所未有的清晰度对伊豆-博宁板块的结构复杂性进行成像。我们解决了北纬 26.5 度至 28 度之间地幔过渡带 (MTZ) 板块中的撕裂。在撕裂以北，板块在 MTZ 中折叠。在折叠铰链正上方，初始剪切区内的粘性耗散可能会导致 P 波速降低的区域。在裂缝以南，板块翻转并平放在 MTZ 底部。类似于2015年博宁680公里地震（Mw-7.9），位于板块倾覆部分的最北边缘。伊豆-小笠原板片的局部撕裂、剪切和屈曲表明它在整个上地幔和过渡带中仍然保持高度粘性。
Seismic tomography provides unique constraints on the morphology, the deformation, and (indirectly) the rheology of subducting slabs. We use teleseismic double-difference P-wave tomography to image with unprecedented clarity the structural complexity of the Izu-Bonin slab. We resolve a tear in the slab in the mantle transition zone (MTZ) between 26.5 degrees N and 28 degrees N. North of the tear, the slab is folded in the MTZ. Immediately above the fold hinge, a zone of reduced P-wavespeed may result from viscous dissipation within an incipient shear zone. To the south of the tear, the slab overturns and lies flat at the base of the MTZ. The similar to 680 km deep 2015 Bonin earthquake (Mw-7.9) is located at the northernmost edge of the overturning part of the slab. The localised tearing, shearing and buckling of the Izu-Bonin slab indicates that it remains highly viscous throughout the upper mantle and transition zone.