Data-oriented constraint on the interpretation of S receiver function and its application to observations of seismic discontinuities in the lithosphere-asthenosphere system
Data-oriented constraint on the interpretation of S receiver function and its application to observations of seismic discontinuities in the lithosphere-asthenosphere system
复制标题
S接收函数解释的面向数据约束及其在岩石圈-软流圈系统地震间断面观测中的应用
DOI：
10.1093/gji/ggz316
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发表时间：
2019
影响因子：
2.8
通讯作者：
Lim Hobin
中科院分区：
文献类型：
--
作者：
Shen Xuzhang;Kim YoungHee;Song Teh Ru Alex;Lim Hobin
本文旨在提高S接收函数（SRF）解释的鲁棒性，S接收函数是一种常用的技术，用于反演起源于台站下方岩石圈-软流圈系统（LAS）的S到P转换波（Sdp）的前向散射。虽然SRF不受后向散射波的干扰，如来自莫霍面的第一次多次波，但该方法的一个主要缺点是Sdp相位会干扰Pcoda波，并且可以想象，这些信号产生的噪声可能被误解为来自地震台站下方LAS的Sdp相位。通过对全波形合成和SRF的系统分析，我们发现，在合成的SRF中，在S波之前的S波中，在主分量波形中的强Pcoda波导致了不需要的信号生成的噪声。如果S波之后的SRF的平均幅度较大，则S波到达之前的可疑信号产生的噪声也较强。在这项研究中，我们荣誉这些不需要的信号产生的噪声的水平，并设计数据为导向的筛选标准，以尽量减少Pcoda波和Pcoda S到P转换波之间的干扰。第一个标准是LQR，直接测量波形数据中的Pcoda波和RadialS波之间的振幅比。第二个标准是AMP，S到达后SRF的幅度。结果表明，这些判据能有效地度量地幔波（如SP波）的能级.与合成和真实的数据，我们证明了LQR和AMP标准的有效性，在最大限度地减少这些不必要的信号产生的噪声在叠加的SRF下降到1- 2%，提高检测阈值和解释的Sdp相位从地震不连续的LAS。
This paper aims to improve the robustness of interpretation in theSreceiver function (SRF), a technique commonly used to retrieve forward scattering ofS-to-Pconverted waves (Sdp) originated from the lithosphere–asthenosphere system (LAS) beneath the stations. Although the SRF does not suffer interferences from backward scattering waves such as the first multiples from the Moho, one major drawback in the method is thatSdpphases can interfere withPcoda waves and it is conceivable that these signal-generated noise may be misinterpreted asSdpphase from the LAS beneath seismic stations. Through systematic analysis of full-waveform synthetics and SRFs from catalogued source parameters, we find that the strongPcoda waves before theSwave in the longitudinal-component waveforms result in unwanted signal-generated noise before theSwave in the synthetic SRFs. If the mean amplitude of SRFs after theSwave is large, dubious signal-generated noise before theSarrival are strong as well. In this study, we honor the level of these unwanted signal-generated noise and devise data-oriented screening criteria to minimize the interference betweenPcoda waves and genuineS-to-Pconverted waves. The first criterion is LQR, a direct measure of the amplitude ratio between longitudinalPcoda waves and radialSwave in the waveform data. The second criterion is AMP, the amplitude of SRFs after theSarrival. We illustrate that these criteria effectively measure the energy level of mantle waves such as theSPwave. With synthetics and real data, we demonstrate the effectiveness of LQR and AMP criteria in minimizing these unwanted signal-generated noise in the stacked SRFs down to 1–2 per cent, improving detection threshold and interpretation ofSdpphases from seismic discontinuities in the LAS.