Investigations of Ambient Noise Velocity Variations in a Region of Induced Seismicity near Greeley, Colorado
Investigations of Ambient Noise Velocity Variations in a Region of Induced Seismicity near Greeley, Colorado
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DOI：
10.1785/0320220033
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发表时间：
2023-01
期刊：
影响因子：
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通讯作者：
Tom Clifford;A. Sheehan;M. Moschetti
中科院分区：
文献类型：
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作者：
Tom Clifford;A. Sheehan;M. Moschetti
自2014年以来，废水注入引发了科罗拉多东北部的地震。我们应用环境噪声相关技术，以确定在该地区的地震速度的时间变化。我们发现，地震速度波动和注入量或地震活动模式之间没有明确的相关性。我们观察到明显的年度变化的速度，可能与水文负荷或热弹性应变。此外，我们模拟均匀和垂直本地化的速度扰动，并测量速度的变化与一维合成地震记录。我们的研究结果表明，我们的方法低估了已知的速度变化，特别是在较短的站距离和变化时，仅限于一个水平层。如果注入确实引起可测量的速度变化，则由于注入威尔斯周围的局部空间范围，其影响可能在互相关中被稀释。
Wastewater injection has induced earthquakes in Northeastern Colorado since 2014. We apply ambient noise correlation techniques to determine temporal changes in seismic velocities in the region. We find no clear correlation between seismic velocity fluctuations and either injection volumes or seismicity patterns. We do observe apparent annual variations in velocity that may be associated with hydrologic loading or thermoelastic strain. In addition, we model uniform and vertically localized velocity perturbations, and measure the velocity change with 1D synthetic seismograms. Our results indicate that our methods underestimate the known velocity change, especially at shorter station distances and when variations are restricted to a horizontal layer. If injection does cause measurable velocity changes, its effect is likely diluted in cross correlations due to its localized spatial extent around injection wells.