Local seismic events recorded by the large‐N Incorporated Research Institutions for Seismology Community Wavefield Experiment in Oklahoma are used to estimate Moho reflections near the array. For events within 50 km of the center of the array, normal moveout corrections and receiver stacking are applied to identify the PmP and SmS Moho reflections on the vertical and transverse components. Corrections for the reported focal depths are applied to a uniform event depth. To stack signals from multiple events, further static corrections of the envelopes of the Moho reflected arrivals from the individual event stacks are applied. The multiple‐event stacks are then used to estimate the pre‐critical PmP and SmS arrivals, and an average Poisson’s ratio of 1.77±0.02 was found for the crust near the array. Using a modified Oklahoma Geological Survey (OGS) velocity model with this Poisson’s ratio, the time‐to‐depth converted PmP and SmS arrivals resulted in a Moho depth of 41±0.6 km⁠. The modeling of wide‐angle Moho reflections for selected events at epicenter‐to‐station distances of 90–135 km provides additional constraints, and assuming the modified OGS model, a Moho depth of 40±1 km was inferred. The difference between the pre‐critical and wide‐angle Moho estimates could result from some lateral variability between the array and the wide‐angle events. However, both estimates are slightly shallower than the original OGS model Moho depth of 42 km, and this could also result from a somewhat faster lower crust. This study shows that local seismic events, including induced events, can be utilized to estimate properties and structure of the crust, which, in turn, can be used to better understand the tectonics of a given region. The recording of local seismicity on large‐N arrays provides increased lateral phase coherence for the better identification of precritical and wide‐angle reflected arrivals.

中文翻译：

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大N阵列附近Moho反射的局部地震事件分析

由俄克拉荷马州大型N地震联合研究机构地震波场实验研究所记录的局部地震事件用于估计阵列附近的Moho反射。对于距阵列中心50公里以内的事件，将应用正常时差校正和接收器叠加来识别垂直和横向分量上的PmP和SmS Moho反射。对报告的焦深的校正将应用于统一的事件深度。为了堆叠来自多个事件的信号，需要对来自各个事件堆栈的Moho反射包络进行进一步的静态校正。然后，使用多事件堆栈来估计临界前PmP和SmS的到来，发现阵列附近地壳的平均泊松比为1.77±0.02。使用具有此泊松比的改良俄克拉荷马州地质调查（OGS）速度模型，经过时间到深度转换的PmP和SmS到来导致Moho深度为41±0.6km⁠。震中到站间距离为90-135 km的选定事件的广角Moho反射模型提供了额外的约束，并且假设使用改良的OGS模型，推断出Moho深度为40±1 km。临界前Moho估计值与广角Moho估计值之间的差异可能是由于阵列与广角事件之间存在一些横向变化而引起的。但是，这两个估算值都比原始OGS模型Moho深度42 km略浅，这也可能是由于下地壳的速度较快所致。这项研究表明，可以利用局部地震事件（包括诱发事件）来估算地壳的性质和结构，反过来，可以用来更好地理解给定区域的构造。大N阵列上的局部地震活动记录提供了增强的横向相位相干性，从而可以更好地识别前临界和广角反射波的到来。