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首页> 外文期刊>Earth, planets and space: EPS >Evidence for an elevated 410 km discontinuity below the Luzon, Philippines region and transition zone properties using seismic stations in Taiwan and earthquake sources to the south
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Evidence for an elevated 410 km discontinuity below the Luzon, Philippines region and transition zone properties using seismic stations in Taiwan and earthquake sources to the south

机译：利用台湾的地震台站和南部的震源，在菲律宾吕宋岛和菲律宾过渡带以下的410 km断面升高的证据

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P waves from earthquakes south of Taiwan, recorded by seismic stations within and around Taiwan, were used to define two average wavespeed models WPSP01 and WPSP02 for the upper mantle and transition zone below the Luzon region. Wavespeeds are characteristic of oceanic upper mantle. The 410-km discontinuity, however, appears to be elevated to about 325 km depth, based on clear identification of the travel-time branch produced by refraction within the transition zone, and estimates of its first and second derivatives with respect to distance. A plausible explanation is low temperatures within the subducted South China Sea plate. The data also imply relatively low wavespeed jumps of 0.6-1.0% and 1.1-1.5% respectively across the elevated 410-km discontinuity and a lower discontinuity at 676 km depth, and high wavespeed gradients in the transition zone. Phase-weighted stacking on a cluster of short-period seismograms with first arrival energy from within the transition zone provides independent support for the validity of the models; later arrivals are detected close to the predicted times and slownesses for energy emerging from the lowermost upper mantle and the top of the lower mantle. An additional arrival on the stacks may be caused by a localized discontinuity near 530 km depth.
机译：台湾南部和台湾地震台站记录的来自台湾南部地震的P波被用来为吕宋地区以下的上地幔和过渡带定义两个平均波速模型WPSP01和WPSP02。波速是海洋上地幔的特征。然而，基于对过渡区内折射产生的行进时间分支的清晰识别，以及对距离的一阶和二阶导数的估计，410 km的不连续性似乎已提高到约325 km的深度。一个合理的解释是俯冲的南海板块内部温度低。数据还表明，在升高的410 km不连续面和676 km深度处较低的不连续面处，相对较低的波速跳跃分别为0.6-1.0％和1.1-1.5％，过渡区域的波速梯度较高。相变加权叠加在过渡带内具有第一到达能量的短周期地震图簇上，为模型的有效性提供了独立的支持。从最下部的上地幔和下部的上地幔顶部涌出的能量，在接近预计时间和慢度的情况下检测到较晚的到达。堆栈上的额外到达可能是由530 km深度附近的局部不连续性引起的。

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