ScP; A probe of ultralow velocity zones at the base of the mantle
ScP; A probe of ultralow velocity zones at the base of the mantle
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DOI：
10.1029/1998gl900319
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发表时间：
1999-02
影响因子：
5.2
通讯作者：
E. Garnero;J. Vidale
中科院分区：
文献类型：
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作者：
E. Garnero;J. Vidale
地核反射相位ScP是地幔底部超低速带（ULVZ）性质的灵敏探针。在合成实验中，一个ULVZ与大凹陷的P和S速度的结果在ScP有两个诊断的前兆和一个后来的到来，其时间取决于ULVZ VP，VS和厚度。如果ULVZ剪切速度有极大的降低，如30%或更大，则附加波至的振幅可能很大。给出了夏威夷短周期和宽频带台阵记录的西南太平洋事件的一些数据实例，这些数据显示了超低电压带的证据。解决所有三个额外的到来将有助于解决强度和比例的VS和VP减少ULVZ，从而部分熔化的问题。
The core‐reflected phase ScP is a sensitive probe of the properties of an ultralow velocity zone (ULVZ) at the base of the mantle. In synthetic experiments, a ULVZ with large depressions in P and S velocities results in ScP having two diagnostic precursors and one later arrival, whose timing depends on ULVZ VP, VS, and thickness. Amplitudes of the additional arrivals can be large if ULVZ shear velocity has extreme reductions, such as 30% and greater. Some data examples are presented for southwest Pacific events recorded at short period and broadband arrays in Hawaii, which show evidence for a ULVZ. Resolving all three additional arrivals will help in addressing the strength and ratio of VS and VP reductions in ULVZ, and thus the issue of partial melt.