Joint ambient noise autocorrelation and receiver function analysis of the Moho
Joint ambient noise autocorrelation and receiver function analysis of the Moho
复制标题
联合环境噪声自相关和莫霍面接收函数分析
DOI：
10.1093/gji/ggab065
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发表时间：
2021
影响因子：
2.8
通讯作者：
F. Tilmann
中科院分区：
文献类型：
--
作者：
S. Mroczek;F. Tilmann
在地震干涉测量领域，互相关用于从环境噪声数据中提取格林函数。通过应用该方法的单站变体，利用自相关，我们原则上能够检索分层地球中的零偏移反射。这些反射很有价值，因为它们不需要主动地震源，并且零偏移距，比基于被动地震的测量更好地限制在空间中。然而，针对具有环境噪声自相关性的莫霍面信号的研究经常给出含糊不清的结果，莫霍面反射不清晰。使用改进的处理方案和相位加权叠加，我们从具有已知简单地壳结构的测试站（印度海得拉巴的 HYB）的垂直自相关迹线中确定莫霍面 P 波反射时间。然而，尽管结构简单，自相关迹线显示了几个与直接反射无关的相位。尽管我们能够以定性方式将其中一些附加阶段与合成建模相匹配，但它们的存在使得在没有先验知识的情况下很难识别反射阶段。该先验知识可以由接收器函数提供。接收器函数（由模式转换产生）对与自相关相同的边界敏感，因此应该具有高度的可比性和组合分析的机会，但其本身无法独立解析 VP、VS 和莫霍面深度。使用接收器函数建议的定时作为指导，我们在北分量的水平自相关上观察到莫霍面 S 波反射，但在东分量上没有观察到。 S 反射的时间与 PpSs-PsPs 接收器函数倍数的时间一致，这也仅取决于 S 速度和莫霍面深度。最后，我们将 P 接收器函数和 HYB 的自相关结合在深度-速度叠加方案中，为我们提供 VP、VS 和莫霍面深度的独立估计。这些发现与几项研究非常一致，这些研究也补充了接收器函数以获得独特的地壳参数。通过将自相关方法应用于穿越中欧波希米亚地块的 EASI 断面的一部分，我们发现与根据接收器函数和站之间的空间相干性确定的莫霍面深度大致一致，从而证明该方法也适用于临时部署。尽管自相关方法的应用在相位识别时需要非常小心，但它有可能结合接收器函数来解析平均地壳 P 和 S 速度以及莫霍面深度。
In the field of seismic interferometry, cross-correlations are used to extract Green’s function from ambient noise data. By applying a single station variation of the method, using autocorrelations, we are in principle able to retrieve zero-offset reflections in a stratified Earth. These reflections are valuable as they do not require an active seismic source and, being zero-offset, are better constrained in space than passive earthquake based measurements. However, studies that target Moho signals with ambient noise autocorrelations often give ambiguous results with unclear Moho reflections. Using a modified processing scheme and phase-weighted stacking, we determine the Moho P-wave reflection time from vertical autocorrelation traces for a test station with a known simple crustal structure (HYB in Hyderabad, India). However, in spite of the simplicity of the structure, the autocorrelation traces show several phases not related to direct reflections. Although we are able to match some of these additional phases in a qualitative way with synthetic modelling, their presence makes it hard to identify the reflection phases without prior knowledge. This prior knowledge can be provided by receiver functions. Receiver functions (arising from mode conversions) are sensitive to the same boundaries as autocorrelations, so should have a high degree of comparability and opportunity for combined analysis but in themselves are not able to independently resolve VP, VS and Moho depth. Using the timing suggested by the receiver functions as a guide, we observe the Moho S-wave reflection on the horizontal autocorrelation of the north component but not on the east component. The timing of the S reflection is consistent with the timing of the PpSs–PsPs receiver function multiple, which also depends only on the S velocity and Moho depth. Finally, we combine P receiver functions and autocorrelations from HYB in a depth–velocity stacking scheme that gives us independent estimates for VP, VS and Moho depth. These are found to be in good agreement with several studies that also supplement receiver functions to obtain unique crustal parameters. By applying the autocorrelation method to a portion of the EASI transect crossing the Bohemian Massif in central Europe, we find approximate consistency with Moho depths determined from receiver functions and spatial coherence between stations, thereby demonstrating that the method is also applicable for temporary deployments. Although application of the autocorrelation method requires great care in phase identification, it has the potential to resolve both average crustal P and S velocities alongside Moho depth in conjunction with receiver functions.
来自被动地震实验的南太平洋超级涌浪下方的横波速度结构
DOI：
--
发表时间：
2008
期刊：
影响因子：
--
作者：
Tanaka;S.
通讯作者：
S.