Radial and Azimuthal Anisotropy Tomography of the NE Japan Subduction Zone: Implications for the Pacific Slab and Mantle Wedge Dynamics
Radial and Azimuthal Anisotropy Tomography of the NE Japan Subduction Zone: Implications for the Pacific Slab and Mantle Wedge Dynamics
复制标题
DOI：
10.1029/2018gl077436
复制
发表时间：
2018-05
影响因子：
5.2
通讯作者：
M. Ishise;H. Kawakatsu;M. Morishige;K. Shiomi
中科院分区：
文献类型：
--
作者：
M. Ishise;H. Kawakatsu;M. Morishige;K. Shiomi
利用走时层析成像技术，从P波方位和径向各向异性研究了日本东北俯冲带的板块和地幔结构。在地幔楔体中发现了具有VPV和GT；VPh的槽状正东西向方位各向异性(AA)和径向各向异性(RA)，支持地幔矿物流动诱导LPO的小尺度对流在地幔楔体中的存在。在俯冲太平洋板块中，得到了具有VPh和Gt；Vpv的海沟平行的N-S走向的AA和RA。考虑到俯冲板块倾角对视各向异性的影响，我们认为这两个特征都可以用俯冲前板块中的AA冻结结构和层流结构来解释。
We investigate slab and mantle structure of the NE Japan subduction zone from P wave azimuthal and radial anisotropy using travel time tomography. Trench normal E‐W‐trending azimuthal anisotropy (AA) and radial anisotropy (RA) with VPV > VPH are found in the mantle wedge, which supports the existence of small‐scale convection in the mantle wedge with flow‐induced LPO of mantle minerals. In the subducting Pacific slab, trench parallel N‐S‐trending AA and RA with VPH > VPV are obtained. Considering the effect of dip of the subducting slab on apparent anisotropy, we suggest that both characteristics can be explained by the presence of laminar structure, in addition to AA frozen‐in in the subducting plate prior to subduction.