Whole‐Mantle Tomography of Southeast Asia: New Insight Into Plumes and Slabs
Whole‐Mantle Tomography of Southeast Asia: New Insight Into Plumes and Slabs
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DOI：
10.1029/2022jb024298
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发表时间：
2022-11
期刊：
影响因子：
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通讯作者：
G. Toyokuni;Dapeng Zhao;K. Kurata
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文献类型：
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作者：
G. Toyokuni;Dapeng Zhao;K. Kurata
我们展示了东南亚及周边地区下方整个地幔P波速度结构的详细三维图像。这些结果是通过应用一种改进的全球地震层析成像方法，对全球14136个台站记录的23587次地震的约800万个P波、pP波、PP波、PcP波和Pdiff波的到时进行反演得到的。我们的层析成像模型揭示了在海南热点下方从地表到核幔边界存在一个连续的、薄的低速（低V）带，这可能反映了存在于整个地幔的海南地幔柱。在俯冲到下地幔的澳大利亚板块下方，检测到一个强烈的低速异常，这可能反映了由于板块俯冲的回流导致的板下热地幔上涌（SHMU）。我们的模型还清晰地揭示了上地幔中的俯冲板块和下地幔中的板块残余。特别是，在爪哇岛东部下方280 - 460千米深处的澳大利亚俯冲板块中发现了一个空洞。澳大利亚板块上方地幔楔中的低速异常通过板块空洞与板下热地幔上涌相连，这表明岛弧岩浆与板下热地幔上涌的混合可能导致了爪哇岛东部坦博拉火山和林贾尼火山的大规模喷发。
We present detailed 3‐D images of the whole mantle P wave velocity structure beneath Southeast Asia and surrounding regions. The results are obtained by applying an improved method of global seismic tomography to invert ∼8 million P, pP, PP, PcP, and Pdiff arrival times from 23,587 earthquakes recorded at 14,136 stations distributed all over the world. Our tomographic model reveals a continuous, thin low‐velocity (low‐V) zone from the surface to the core‐mantle boundary beneath the Hainan hotspot, which may reflect the Hainan plume that exists in the whole mantle. Beneath the Australian slab that has subducted into the lower mantle, a strong low‐V anomaly is detected, which may reflect subslab hot mantle upwelling (SHMU) due to return flow of the slab subduction. Our model also clearly reveals the subducted slabs in the upper mantle and slab remnants in the lower mantle. In particular, a hole in the subducting Australian slab is revealed at depths of 280–460 km beneath eastern Java. The low‐V anomaly in the mantle wedge above the Australian slab is connected with the SHMU through the slab hole, suggesting that mixture of the island arc magma and the SHMU may have caused huge eruptions of the Tambora and Rinjani volcanoes in eastern Java.