Source parameter analysis using distributed acoustic sensing – an example with the PoroTomo array
Source parameter analysis using distributed acoustic sensing – an example with the PoroTomo array
复制标题
使用分布式声学传感进行源参数分析 — 以 PoroTomo 阵列为例
DOI：
10.1093/gji/ggad061
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发表时间：
2023
影响因子：
2.8
通讯作者：
Chen, Xiaowei
中科院分区：
文献类型：
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作者：
Chen, Xiaowei
在这项研究中，我证明了分布式声学传感（DAS）的原始应变率数据可以直接用于估计光谱源参数通过经验绿色函数（EGF）反卷积分析。在此之前，DAS已广泛用于被动地震学，通过在分析之前将应变或应变率转换为质点速度或加速度来对地下进行成像并分析地面运动变化。在这项研究中，频谱分析应用于PoroTomo联合DAS和地震节点阵列在布雷迪温泉地热田获得两个M4地震的震源参数通过EGF分析，其中近并列的小事件被用作EGF，以消除路径和场地效应。EGF工作流程应用于原始DAS应变率数据，而不转换为粒子速度和原始节点地震数据。DAS和Nodal的结果非常一致，对于相同的事件对，谱比、角频率和矩比具有相似的特征。由于堆叠光谱测量的不确定性在DAS阵列上低得多，表明光谱形状测量的更好的稳定性，这可能是由于更密集的空间采样。由于模型拟合的不确定性在DAS和节点阵列之间相似，DAS阵列上的不确定性略低。这些观测结果表明，直接使用DAS阵列的应变率测量的震源特性的潜力。
In this study, I demonstrate that distributed acoustic sensing (DAS) raw strain rate data can directly be used to estimate spectral source parameters through an Empirical Green's Function (EGF) deconvolution analysis. Previously, DAS had been widely used in passive seismology to image the subsurface and analyze ground motion variations by converting strain or strain rate to particle velocity or acceleration prior to analysis. In this study, spectral analysis is applied to the PoroTomo joint DAS and seismic Nodal array in the Brady Hot Springs geothermal field to obtain source parameters for two M4 earthquakes via EGF analysis, where nearly collocated smaller events are used as an EGF to remove path and site effects. The EGF workflow is applied to raw DAS strain rate data without conversion to particle velocities and raw Nodal seismic data. The DAS and Nodal results are very consistent with similar features of spectral ratios, corner frequencies and moment ratios for the same event pairs. The uncertainty due to stacked spectral measurement is much lower on the DAS array, suggesting better stability of spectral shape measurement, possibly due to the much denser spatial sampling. The uncertainty due to model fitting is similar between DAS and Nodal arrays with slightly lower uncertainty on the DAS array. These observations demonstrate potential for directly using the strain rate measurements from DAS arrays for earthquake source characterizations.