Detection of a ULVZ at the base of the mantle beneath the northwest Pacific
Detection of a ULVZ at the base of the mantle beneath the northwest Pacific
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DOI：
10.1029/2009gl039387
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发表时间：
2009-09
影响因子：
5.2
通讯作者：
Yan Xu;K. Koper
中科院分区：
文献类型：
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作者：
Yan Xu;K. Koper
我们使用黄刀地震阵列（YKA）测量了发生在环太平洋地区地震的1371个P波和Pdiff波的慢度。相应的P - velocity异常表明，在西北太平洋下的一块横向尺寸为数百公里的最下层地幔上，P - velocity急剧减少了6%。这个超低速度带（ULVZ）的位置与概率地幔层析成像显示的长波成分边界有关。我们将ULVZ解释为古板块物质从西北太平洋俯冲带向太平洋中南部大的、化学性质不同的省份横向移动时产生的部分熔融。
We used the Yellowknife seismic array (YKA) to measure the slowness of 1,371 P and Pdiff waves from earthquakes occurring in the circum‐Pacific region. The corresponding anomalies in P‐velocity show a sharp reduction of up to 6% across a patch of the lowermost mantle beneath the Northwest Pacific with lateral dimensions of several hundred kilometers. The location of this ultra low velocity zone (ULVZ) correlates with a long‐wavelength compositional boundary revealed by probabilistic mantle tomography. We interpret the ULVZ as partial melt created by paleo‐slab material that is being swept laterally from northwestern Pacific subduction zones towards the large, chemically distinct province beneath the south‐central Pacific.