Azimuthal Anisotropy Tomography of the Southeast Asia Subduction System
Azimuthal Anisotropy Tomography of the Southeast Asia Subduction System
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DOI：
10.1029/2021jb022854
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发表时间：
2022-02-01
影响因子：
3.9
通讯作者：
Xu, Yi-Gang
中科院分区：
文献类型：
--
作者：
Hua, Yuanyuan;Zhao, Dapeng;Xu, Yi-Gang
通过联合反演当地地震到时和相对走时残差，得到了东南亚地区P波各向同性速度和方位各向异性的三维模型。我们的研究结果表明，高速（高V）俯冲澳大利亚板片已经穿过地幔过渡区（MTZ），并达到了苏门答腊岛下的深度约为1,200公里，而高V板片已经向北俯冲，并被困在爪哇岛下的MTZ。海南地幔柱清晰地显示为MTZ下方的显著低速异常，该异常向下延伸至我们模型的底部（类似于1，600 km深度）。海南地幔柱的上涌受到MTZ中的停滞板的抵制，导致停滞板下方方位各向异性的快速度方向发散。详细的地震层析成像和方位各向异性的结果提供了重要的新信息的复杂的地幔结构和动力学的东南亚地区，特别是俯冲板片和海南柱，以及它们之间的相互作用。
A detailed 3-D model of P wave isotropic velocity and azimuthal anisotropy beneath SE Asia is obtained by jointly inverting local earthquake arrival times and teleseismic relative travel-time residuals. Our results show that the high-velocity (high-V) subducting Australian slab has penetrated through the mantle transition zone (MTZ) and reached a depth of similar to 1,200 km beneath Sumatra, whereas the high-V slab has subducted toward the north and trapped within the MTZ beneath Java. The Hainan mantle plume is revealed clearly as a significant low-velocity anomaly beneath the MTZ, which extends down to the bottom of our model (similar to 1,600-km depth). The upwelling of the Hainan plume is resisted by the stagnant slab in the MTZ, resulting in divergent fast-velocity directions of azimuthal anisotropy beneath the stagnant slab. The detailed results of seismic tomography and azimuthal anisotropy provide important new information on the complex mantle structure and dynamics of the SE Asian region, in particular, the subducting slabs and the Hainan plume, as well as their interactions.