Rupture processes and magnitude statistics of inducedearthquakes and aftershocks: A detailed view from deepSouth African gold mines

尽管我们对地震过程有了一般的了解，但仍然没有完全理解地震破裂是如何成核和传播的，以及它们为什么会停止。此外，地震频率和规模的控制因素是正在进行的研究的主题。在我们的建议中，我们的目标是通过对南非深层金矿地震活动的全面研究来解决这些问题。在这里，我们发现了独特的情况，地震活动包括两个采矿诱发地震和触发余震。我们假设，无论是采矿活动或主震的应力扰动量的有限性和几何形状，控制破裂的成核和传播，并影响频率-幅度分布。为了验证我们的假设，我们将采用新的方法从深矿井地震活动，其中涉及基于波形和概率的方法。这些方法是最近制定的，并成功地应用于流体注入诱发地震，包括破裂传播成像，破裂方向性分析，并研究规模的统计。在本提案中，我们希望测试这些方法对南非深部矿井地震活动的适用性，这也发生在有限的体积中，这将有助于更好地了解地震孕育过程，特别是改善采矿环境中地震危险的评估和减轻。

Despite our general understanding of earthquake processes, it is still not fully understood how earthquakes ruptures nucleate and propagate and why they stop. Furthermore, the controlling factors of the frequency and the size of earthquake are subject of ongoing research. In our proposal, we aim to address these questions with a comprehensive study of seismicity in deep South African gold mines. Here, we find the unique situation that the seismicity consists of both mining-induced earthquakes and triggered aftershocks. We hypothesize that the finiteness and geometry of the volume of stress perturbation, either by mining activity or by a main shock, controls the nucleation and propagation of ruptures and influences the frequency-magnitude distribution. To test our hypothesis, we will apply novel approaches to the seismicity from the deep mines which involve both waveform-based and probabilistic methods. These methods were recently elaborated and successfully applied to fluid injection induced earthquakes and include rupture propagation imaging, rupture directivity analysis, and studies of the scaling of the magnitude statistics. In this proposal, we want to test the applicability of these approaches to the seismicity in deep South African mines, which also occurs in a finite volume, which will contribute to a better understanding of seismogenic processes and, in particular, to an improved assessment and the mitigation of seismic hazard in mining environment.