Underground exploitation of georesources can be highly correlated with induced seismic activity. In order to reduce the risk and improve the mining operations safety, the mining activity is monitored by a dedicated seismic network. Moment tensor inversion is a powerful method to investigate the rupture process of earthquakes in mines, providing information on the geometry of the earthquake source and the moment release. Different approaches have been proposed to estimate the source mechanisms, with some advantages and limitations. One of the simplest and most used methods rely on the fit of the polarity and amplitude of first P wave onsets. More advanced techniques fit the full waveforms and their spectra. Here, we test and compare moment tensor and focal mechanism estimations for both inversion techniques. In order to assess the inversion resolution, we built realistic synthetic data, accounting for real seismic noise conditions and network geometry for the Rudna copper mine, SW Poland. The Rudna mine pertains to the Legnica-Glógow Copper District, where thousands of mining induced earthquakes are detected yearly, representing a serious hazard for miners and mining infrastructures. We simulate a range of different processes and locations, considering pure double couple, deviatoric and full moment tensors with different magnitudes and located in different mining panels. Results show that the P-wave first onset inversion is very sensitive to the geometry of the seismic network, which is limited by the existing underground infrastructure. On the other hand, the quality of the moment tensor solutions for the full waveform inversion is mainly determined by the strength of mining tremor and the signal-to-noise ratio. We discuss the performance of both inversion techniques and provide recommendations towards a reliable moment tensor analysis in mines.

中文翻译：

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如何评估采矿诱发地震活动的矩张量反演分辨率：以波兰 Rudna 矿为例。

地质资源的地下开发与诱发地震活动高度相关。为了降低风险并提高采矿作业的安全性，采矿活动由专门的地震网络监测。矩张量反演是研究矿井地震破裂过程的有力方法，可提供有关震源几何形状和矩释放的信息。已经提出了不同的方法来估计源机制，具有一些优点和局限性。最简单和最常用的方法之一依赖于第一个 P 波起始的极性和幅度的拟合。更先进的技术适合完整的波形及其频谱。在这里，我们测试和比较两种反演技术的矩张量和焦点机制估计。为了评估反演分辨率，我们构建了真实的合成数据，考虑了波兰西南部 Rudna 铜矿的真实地震噪声条件和网络几何结构。Rudna 矿属于 Legnica-Glógow 铜区，在那里每年检测到数以千计的采矿诱发地震，对矿工和采矿基础设施构成严重危害。我们模拟了一系列不同的过程和位置，考虑了具有不同量级并位于不同采矿面板中的纯双偶、偏矩和全矩张量。结果表明，P 波初发反演对地震台网的几何形状非常敏感，这受到现有地下基础设施的限制。另一方面，全波形反演矩张量解的质量主要由矿震强度和信噪比决定。我们讨论了两种反演技术的性能，并为矿山中可靠的矩张量分析提供了建议。