Crust-mantle boundary contraints from ambient noise autocorrelations in North America

地幔岩石圈和软流圈对内华达山脉及其邻近省份的构造过程起着关键作用。尽管进行了许多创新性研究，但山脉隆起差异的原因(南北方的隆起高于北纬的隆起)、南纬向地壳厚度自东向西急剧变化的原因、地壳分层和局部“亮度”以及地幔波速与地形和地表地质的关系仍在争论之中。壳-幔边界(MOHO)的新的独立约束将有助于回答这些问题，然而，由于缺乏良好的震源和接收器几何空间分布，MOHO深度和性质往往难以用地震方法解决。该项目的目标是应用一种新的壳幔边界分析方法，与接收器函数不同，该方法不依赖于大型记录的地震事件。此外，与目前的反射/折射地震研究相比，新方法在所有可用的地震传感器上都得到了局部应用，提供了前所未有的分辨率。研究人员的目标是估计和解释新的、独立的地壳深度模型。通过分析从环境噪声自相关中提取的格林函数的体波分量(P和S)，得到了内华达山脉的地幔边界(莫霍面)。他们将使用环境噪声地震干涉术来提取壳幔边界格林函数反射分量。我们的工作包括以下三个阶段：1)根据公开的信息更新研究区现有的全面地震数据库，包括P/S地震速度模型和接收器函数；2)对研究区内每个可用的传感器应用环境-地震噪声自相关，目的是识别、提取和分析格林函数的P/S反射分量。3)利用波形模拟将新的地壳模型估计到一阶，与接收函数估计进行统计比较，并根据检验的假设对结果进行解释。在这个项目中，他们正在应用一种名为地震干涉测量的创新数据处理方法来估计壳-地幔边界深度和性质。这项研究预计将为北美西部提供新的、独立的地震地壳模型约束，重点是内华达山脉和邻近地区。与目前使用的其他方法(如接收函数估计)不同，我们的方法不依赖于大的记录地震事件。当应用于所有可用的地震传感器时，这种新方法也具有前所未有的分辨率。

The mantle lithosphere and asthenosphere hold a key to tectonic processes in the Sierra Nevada (SN) and the adjacent provinces. Although addressed by many innovative studies, the causes of differences in the mountain range uplift (higher in the southern SN compared to the uplift in the northern SN), the cause of dramatic variations in SN crustal thickness from east to west, of crustal layering and local "brightness", and the mantle wave speeds relation to topography and surface geology are still under debate. New, independent constraints on crust-mantle boundary (Moho) would help answer these questions, however, Moho depth and properties are often difficult to resolve seismically because of the lack of favorable spatial distribution of source and receiver geometries. The goal of this project is to apply a new method for crust-mantle boundary analysis, which, in contrast to receiver functions, does not depend on large recorded seismic events. Also, in contrast to current reflection/refraction seismic studies, the new method is applied locally at all available seismic sensors, providing unprecedented resolution. The investigators aim to estimate and interpret new, independent models of the depth of the crust ? mantle boundary (Moho discontinuity) across the Sierra Nevada, through analysis of the body wave component (P and S) of Green's Functions extracted from ambient noise autocorrelations. They will use ambient-noise seismic interferometry to extract the crust-mantle boundary Green's Function reflection component. Our activity consists of three stages, as follows:1) Update an existing, comprehensive seismic database in the study area, including P/S seismic velocity models and receiver functions, from publicly available information; 2) Apply ambient-seismic noise autocorrelations to each available sensor in the study area, with the purpose to identify, extract and analyze the P/S reflection component of the Green's Functions. 3) Estimate to the first order the new crustal models using waveform modeling; statistically compare with receiver function estimates and interpret the results in terms of the tested hypotheses. In this project they are applying an innovative data processing method named seismic interferometry to estimate the crust-mantle boundary depth and properties. The study is expected to provide new, independent seismic crustal model constraints for western North America, with focus on the Sierra Nevada and the adjacent regions. In contrast to other currently used procedures, such as receiver function estimates, our method does not depend on large recorded seismic events. This new method also has unprecedented resolution, when applied at all available seismic sensors