A new insight into the Hawaiian plume
A new insight into the Hawaiian plume
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DOI：
10.1016/j.epsl.2005.11.038
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发表时间：
2006-01
影响因子：
5.3
通讯作者：
J. Lei;Dapeng Zhao
中科院分区：
文献类型：
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作者：
J. Lei;Dapeng Zhao
虽然许多地球化学、地球物理和地震学研究表明夏威夷地幔柱起源于核幔边界（CMB），但由于夏威夷岛链上的地震台站很少，到目前为止，还没有层析成像模型显示夏威夷地幔柱在整个地幔中的连续图像。本文给出了从国际地震中心的地震资料集中提取的P、pP、PP、PcP、Pdiff、PKPab、PKPbc、PKIKP、PKKPab和PKKPbc等10种震相同时测定的夏威夷地下新的层析成像。其中PKiKP、PKKPab和PKKPbc是首次尝试用于全球地震层析成像。我们的研究结果表明，一个缓慢的异常夏威夷下上升，不断从CMB到表面，这意味着夏威夷羽确实起源于CMB。这幅图像比以前在整个地幔，特别是在中地幔和以下的结果显着改善，这表明后期阶段，PP，Pdiff，PKP，特别是PKiKP，是非常重要的夏威夷羽更好地成像。这种缓慢的异常被认为是一个正在倾斜的地幔柱通道，这可能是由地幔流动引起的。这表明夏威夷热点在地表上的位置不是静止的，正如最近的古地磁和数值模拟研究所证明的那样。
Although many geochemical, geophysical and seismological studies have suggested that the Hawaiian mantle plume originates from the core–mantle boundary (CMB), so far no tomographic model shows a continuous image of the Hawaiian plume in the entire mantle because of the few seismic stations on the narrow Hawaiian island chain. Here we present a new tomographic image beneath Hawaii determined by using simultaneously 10 kinds of seismic phases, P, pP, PP, PcP, Pdiff, PKPab, PKPbc, PKiKP, PKKPab and PKKPbc, extracted from the data set compiled by the International Seismological Center. Of these phases, PKiKP, PKKPab and PKKPbc are, for the first time, attempted to use in the global seismic tomography. Our results show a slow anomaly beneath Hawaii ascending continuously from the CMB to the surface, implying that the Hawaiian plume indeed originates from the CMB. This image is improved notably over the previous results in the whole mantle, particularly in and below the middle mantle, suggesting that later phases, PP, Pdiff, PKP and particularly PKiKP, are of great importance for better imaging the Hawaiian plume. This slow anomaly is considered to be a plume conduit being tilted, which is likely caused by the mantle flow. This indicates that the position of the Hawaiian hotspot on the surface is not stationary, as evidenced by the recent paleomagnetic and numerical modeling studies.