School of Earth and Space Sciences; Laboratory of Seismology and Physics of Earth's Interior, University of Science and Technology of China, 96 Jinzhai Road, Hefei, 230026, Anhui, China.
CAS Center for Excellence in Comparative Planetology, 96 Jinzhai Road, Hefei, 230026, Anhui, China.
Nat Commun. 2019 Mar 21;10(1):1310. doi: 10.1038/s41467-019-09279-7.
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° N and 28° 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 680 km deep 2015 Bonin earthquake (Mw7.9) 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.
地震层析成像为俯冲板块的形态、变形（间接）以及流变学提供了独特的约束条件。我们使用远震双差 P 波层析成像，以前所未有的清晰度对伊豆-小笠原板块的结构复杂性进行成像。我们在 26.5°N 和 28°N 之间的地幔过渡带（MTZ）中解析到了一个板块的撕裂。在撕裂以北，板块在 MTZ 中褶皱。在褶皱枢纽上方，可能由于初始剪切带内的粘性耗散导致 P 波速度降低区。在撕裂以南，板块翻转并在 MTZ 底部平躺。深度约为 680 公里的 2015 年小笠原地震（Mw~7.9）位于板块翻转部分的最北端。伊豆-小笠原板块的局部撕裂、剪切和弯曲表明，它在整个上地幔和过渡带中仍然具有很高的粘性。
