Abstract—Despite extensive research, it is still unclear, to what extent studying the parameters of weak seismicity facilitates the interpretation of the data obtained from moderate and strong earthquakes. In this paper, we analyze seismic events initiated by mine explosions at the Korobkovskoe iron ore deposit of the Kursk Magnetic Anomaly, central East European platform. The study region is distinguished by the excess of horizontal stresses over vertical stresses and is declared as a potentially rock-burst prone massif although mining-induced rock bursts have not been observed so far. In this analysis, we use the data from a seismic network of four one-component horizontal accelerometers installed in the mine. After the detection and location of weak seismic events, their source parameters were estimated based on the Brune model spectrum approximation. It was established that the sources of the recorded seismic events are densely clustered in space in the vicinity of the closest explosion room and most sources are located within a domain with a level of the explosion-induced dynamic strains higher than 10^–6. The calculated moment magnitudes vary from –2.7 to –1.4. The stress drop is estimated to range from 0.002 to 0.25 MPa with the apparent stress values varying from 0.0003 to 0.017 MPa. The scaled seismic energy \({{{{E}_{s}}} \mathord{\left/ {\vphantom {{{{E}_{s}}} {{{M}_{0}}}}} \right. \kern-0em} {{{M}_{0}}}}\) increases from 10^–8 to 10^–7 J/(N m) as the seismic moment changes from 1.5 × 10⁵ to 1.5 × 10⁶ N m. This trend is not observed in the interval of moments from 10⁶ to 10⁷ N m. In our opinion, this effect can probably be associated with the decrease in the shear modulus of the rock with the increase of the event size. The calculated values of the scaled energy and rupture propagation velocity indicate that the industrial explosion has probably initiated a series of microearthquakes with low radiation efficiency.

摘要——尽管进行了广泛的研究，但目前还不清楚，研究弱地震活动参数在多大程度上有助于解释中强地震数据。在本文中，我们分析了由东欧中部平台库尔斯克磁异常的 Korobkovskoe 铁矿床的矿山爆炸引发的地震事件。研究区域的特点是水平应力超过垂直应力，并被宣布为潜在的岩爆易发地块，尽管迄今为止尚未观察到采矿引起的岩爆。在此分析中，我们使用来自安装在矿井中的四个单分量水平加速度计的地震网络数据。在对弱地震事件进行检测和定位后，基于Brune模型谱近似估计其震源参数。^–6 . 计算出的力矩大小从 –2.7 到 –1.4 不等。应力降估计在 0.002 到 0.25 MPa 的范围内，表观应力值从 0.0003 到 0.017 MPa 不等。缩放后的地震能量\({{{{E}_{s}}} \mathord{\left/ {\vphantom {{{{E}_{s}}} {{{M}_{0}}} }} \right. \kern-0em} {{{M}_{0}}}}\)从 10 ^–8增加到 10 ^–7 J/(N m) 当地震矩从 1.5 × 10 ⁵变为1.5 × 10 ⁶ N·m。在 10 ⁶到 10 ⁷的时刻间隔内没有观察到这种趋势牛米。我们认为，这种效应可能与岩石剪切模量随着事件大小的增加而降低有关。标度能量和破裂传播速度的计算值表明，工业爆炸可能引发了一系列低辐射效率的微地震。