当前位置: X-MOL 学术Geophys. Res. Lett. › 论文详情
Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)
High‐Frequency (6 Hz) PKPab Precursors and Their Sensitivity to Deep Earth Heterogeneity
Geophysical Research Letters ( IF 5.2 ) Pub Date : 2020-12-22 , DOI: 10.1029/2020gl089203
C. Sens‐Schönfelder 1 , K. Bataille 1, 2 , M. Bianchi 3
Affiliation  

We present observations on a new precursory phase of seismic waves scattered in the deep Earth. This phase arrives prior to the PKPab wave at epicentral distances larger than 155°, and we call it PKPab precursor. We show that the presence of the PKPab precursor is a necessary consequence of scattering in D″, which is the commonly accepted cause of the PKPdf precursor at distances smaller than 145°. PKPdf waves that propagate through the inner core should arrive before the PKPab precursor but those, are strongly attenuated in the inner core at frequencies between 4 Hz and 8 Hz used here, making the PKPab precursor the earliest teleseismic signal at distances larger than 155°. Calculated PKPab precursor sensitivity kernel shows that this phase is mostly sensitive to scattering along the closest PKPbc path between source and receiver. It can thus help to constrain the lateral distribution of heterogeneity along D″.

中文翻译:

高频(6 Hz)PKPab前体及其对深层地球异质性的敏感性

我们提出了关于在地球深处散射的地震波的新的前兆相的观测结果。这个阶段在PKPab波之前到达震中,距离大于155°,我们称之为PKPab前驱体。我们表明,PKPab前体的存在是在D''中散射的必要结果,这是PKPdf前体在小于145°的距离处被普遍接受的原因。穿过内芯传播的PKPdf波应在PKPab前驱体之前到达,但在此处使用的4 Hz至8 Hz频率下,它们在内芯中被强烈衰减,从而使PKPab在距离大于155°的距离之前发出最早的远震信号。计算得出的PKPab前体敏感度内核表明,该阶段对沿源和接收器之间最接近的PKPbc路径的散射最敏感。因此,它可以帮助约束沿着D''的异质性横向分布。
更新日期:2021-01-24
down
wechat
bug