Intense seismic scattering near the Earth's core‐mantle boundary beneath the Comoros hotspot
Intense seismic scattering near the Earth's core‐mantle boundary beneath the Comoros hotspot
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DOI：
10.1029/2000gl011831
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发表时间：
2000-11
影响因子：
5.2
通讯作者：
L. Wen
中科院分区：
文献类型：
--
作者：
L. Wen
我报告坦桑尼亚地震台记录了斐济俯冲带发生的强烈地震 PKP 前兆。观察到的 PKP 前兆显示出不同事件和站点的明显起始和振幅的快速变化。我开发了一种技术，使用前兆发生时间来确定地震散射体的位置，并应用前兆振幅的正向建模来限制地震异常的震级。走时分析表明，这些记录的 PKP 前兆是由科摩罗热点下方地幔最低 360 公里处的地震散射引起的。观测到的 PKP 前兆的振幅表明存在相当复杂的地震结构，P 速度变化至少为 8%，可能与部分熔融有关。
I report strong seismic PKP precursors recorded in the seismic stations in Tanzania for earthquakes occurred in the Fiji subduction zone. The observed PKP precursors show clear onsets and rapid variations of amplitude for different events and stations. I develop a technique to use the precursor onset times to determine the location of seismic scatterers and apply forward modeling of precursor amplitudes to place constraints on the magnitude of seismic anomalies. The travel time analysis indicates that these recorded PKP precursors are caused by the seismic scattering in the lowermost 360 km of the mantle beneath the Comoros hotspot. The amplitudes of the observed PKP precursors suggest a rather complex seismic structure with a P velocity variation of at least 8%, likely associated with partial melt.