“Double Door” Opening of the Japan Sea Inferred by Pn Attenuation Tomography
“Double Door” Opening of the Japan Sea Inferred by Pn Attenuation Tomography
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DOI：
10.1029/2022gl099886
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发表时间：
2022-08
影响因子：
5.2
通讯作者：
Ge Yang;Lian‐Feng Zhao;Xiao-Bi Xie;Xi He;Yan Lü;Z. Yao
中科院分区：
文献类型：
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作者：
Ge Yang;Lian‐Feng Zhao;Xiao-Bi Xie;Xi He;Yan Lü;Z. Yao
大洋岩石圈俯冲后弧后盆地的伸展和边缘海的形成通常归因于俯冲板块的退缩和扭曲的地幔对流。然而，对于西北太平洋最大的边缘海日本海来说，由于同时代的菲律宾板块俯冲和弧形弧形火山带，日本海的开放不太可能仅仅是太平洋板块俯冲的结果。因此，可以直接受强Pn波衰减制约的上地幔现今热结构对理解日本海开放具有重要意义。在这里，我们观察到了日本海下的两个Pn强衰减带，它们的走向与当地Pn各向异性以及太平洋和菲律宾海沟的撤退方向基本一致。因此，在最上面的地幔中似乎有两个发散的地幔流动，为日本海的开放推了一扇“双扇门”。
The extension of back‐arc basins and formation of marginal seas following the subduction of oceanic lithosphere are usually attributed to the rollback of subducting slabs and distorted mantle convection. However, for the Japan Sea, the largest marginal sea in the northwestern Pacific, its opening is unlikely only resulted from the subduction of the Pacific plate because of the coeval Philippine plate subduction and the arcuate arc volcanic zone. Therefore, the present‐day thermal structure in the uppermost mantle, which can be directly constrained by strong Pn‐wave attenuation, plays a vital role in understanding the Japan Sea opening. Here, we observe two belts of strong Pn attenuation beneath the Japan Sea; their strikes are generally consistent with local Pn anisotropy and the retreat directions of the Pacific and Philippine trenches. Hence, there seem to be two divergent mantle flows in the uppermost mantle, pushing a “double door” for the Japan Sea opening.