Natural and induced seismic activity in Kuzbass

Based on the plotted times of occurrence of seismic events, their timing within a work week and location of epicenters, it is illustrated that since the 1960s the seismicity in the Kuzbass territory has been a complicated natural and mining-induced phenomenon. Since the late 1980s, the natural and mining-induced seismicity has entered the second stage of development, with clustering of low-energy seismic events and strong shallow earthquakes in the areas under heavy mining and, in the first instance, at deep open pit mines. The representative event of this kind is the magnitude 5.2 earthquake at the Bachatsky Coal Open Pit Mine on June 19, 2013. It has been found that the natural and induced seismic activity is associated with deep faults that weakly show themselves in the upper layer of the earth crust but appear in the local relief, which is an evidence of their live emergence onto the daylight surface due to the mining impact. The article proposes the comprehensive research program for the natural and mining-induced seismic activity in the Kuzbass area and the development of early identification of seismically active zones.     

矿山微震震源机制的初步研究

矿山微震震源机制是揭示和认识矿震发生机理,从事矿山微震监测预报、矿震灾害防治的基础和前提,也是从事矿震研究的理论基础之一。根据完整岩石破裂机理,从刚度理论的角度论证了岩石动力破坏的理论条件;在总结矿山常见的岩体破坏类型的基础上,对几种基本的矿震机制进行了全面的论述。     

Modern seismicity in mining areas in the Murmansk Region

The Murmansk Region in the northeastern Baltic Shield has been for long assumed as aseismic. Initiated in the 1950s, the regular instrumental seismological studies allow new data on the essential increment in seismicity, demonstrated in the maps of the general seismic zoning of the territory of Russia. Powerful mining industry in the Murmansk Region also induces many seismic events. This article analyzes natural and induced seismicity and their cross-effect.     

Seismic imaging of rock mass responses to excavation

Three case studies are presented which illustrate rock mass characterization using a combination of tomographic images of spatial variation in seismic p-wave velocity with induced seismicity. In the controlled case of a tunnel excavation, known stress changes and fracturing were successfully mapped using velocity images and the location of induced seismicity. Within a stabilizing pillar in a deep South African gold mine, an active-source velocity image resolved the location of stress concentrations ahead of the mining face, and fracturing around the stope. Velocity images of pre-existing, seismically active faults were also computed by simultaneously inverting the induced seismicity data for velocity structure and hypocentral location. The resulting velocity image was interpreted in terms of the expected deformation and seismic potential along the faults. The potential role of velocity imaging and induced seismicity in validating geomechanical models is discussed, along with a possible strategy for incorporating the technique into an integrated geomechanical investigation of induced seismicity.     

Low-magnitude seismicity monitoring in rocks

The authors calculate possible errors in characterization of low-magnitude seismicity sources using the Brune model and methods of identification of seismic event energy class and local magnitude. The adequacy of the model has been proved by comparing its results with the recordings of seismic vibrations in the North Ural Bauxite Mine. The errors due to the drastic distortion of the emission spectrum become significant at the distance of 1000 m from the emission source and grow as the distance increases. Cases of great deviations from the similarity law are analyzed based on the actual seismic monitoring in the North Ural Bauxite Mine, in mines in Poland, Finland and Canada, as well as in water basins. It is shown that phenomena due to physical difference of various size fracturing dynamics do not radically change a seismic source capacity. Other causes, due to instrumentation shortcomings or incorrect data interpretation, may result in overestimated seismic energy and scaling-up of low-magnitude seismic events.     

煤矿沉陷区的新农村建设模式

煤矿开采必将造成土地塌陷及其上方的建(构)筑物损害,特别是我国目前开采的煤矿区多位于人口相对密集的地区,开采对土地、农村民房等的损害相对严重。从国家建设社会主义新农村重大决策出发,结合土地保护、环境保护的要求,利用煤矿开采地表沉陷规律,探讨了煤矿沉陷区(影响区)新农村建设的特点,提出了煤矿沉陷区农村建设走"统筹兼顾、合理规划、环境保护、土地保护、三方付担(企业、农民、地方政府)、三方收益"的"大村庄制"模式。     

强矿震临界破裂阶段的岩体弹性波场

为探索井田范围较大尺度岩体破裂失稳的危险性预测,以抚顺老虎台井田为工程背景,反演连续12个月矿震弹性波的传播速度比（v_P/v_S）和质点振动振幅比（A _S/A _P）,分析强矿震临界发生阶段的弹性波场变异特征。结果显示,M_L≥1.5矿震的波场信息较敏感,在M L≥3.0（E≥1.8×10⁸J弹性能）矿震前,波速比和振幅比绝大多数存在显著的低值异常,预测M _L≥3.0矿震的信度分别为0.79和0.93,虚假异常和缺失异常较少,具有良好的应用前景。波速比和振幅比在强矿震临界破裂前存在的降低和恢复过程,可能指示能量核心区岩体的张性破裂扩容和裂隙闭合过程。     

Triggered Seismicity in a Flooded Former Coal Mining Basin (Gardanne Area,France)

We studied the correlation between seismicity and the water table level in an abandoned coal mine (Bouches-du-Rhône, France), closed in 2003, where groundwater has been pumped out since 2010 to prevent underground flooding. Microseismicity was first felt by the population in 2010 and a strongly felt seismic swarm occurred in November 2012. The origin of the seismicity was therefore questioned, in relation to both the potential instability of old, shallow galleries that might generate damage at the surface and a local seismic hazard assessment. A temporary dense seismic network in the area allowed us to analyse the spatial distribution of the seismicity in detail. Most of the seismicity was clearly located under the mine workings, highlighting that an existing fault system crossing the mining operation was being hydraulically activated, in accordance with the known tectonic extension regime. Our analysis clearly shows a spatiotemporal relationship between seismic migration and the level of the mine aquifer between 2013 and 2017. Thus, seismicity will persist with oscillations of the mining aquifer, depending on the pumping capacities and effective rainfall. Continuous hydraulic and seismic monitoring is necessary to better understand these phenomena and assess the associated risks.

     

Natural and Technogenic Seismicity of the Ural Region

Common characteristics of the seismicity in the Ural Region are considered. New approaches to control of natural and technogenic earthquakes are described. These approaches have become possible owing to the up-to-date seismological network of 6 digital seismic stations developed in the Western Ural. The data obtained during continuous 4 year monitoring ensured the first-time conducted integral estimation of the natural-to-technogenic seismicity levels in the region in question.__________Translated from Fiziko-Tekhnicheskie Problemy Razrabotki Poleznykh Iskopaemykh, No. 1, pp. 9–18, January–February, 2005.     

Optimal spatial distribution of seismic stations in mines

A procedure is developed for obtaining the optimal spatial distribution of seismic stations in mines. The optimality criterion is derived from the theory of optimal experiment. An optimal seismic network is one such that the spatial distribution of the stations with respect to the hypocenter position of the seismic event gives the best possible precision for the hypocenter parameters. The approach allows, when needed, to take into consideration: (i) different probability of event occurrence at different mining areas; (ii) planning for the best estimates of selected parameter as for example epicenter coordinates; (iii) building a network that is optimal for location of seismic events within a specified range of seismic energy.Four applications, two hypothetical and two in actual mines in Canada and in South Africa, respectively, show that the proposed procedure for optimal distribution of seismic stations provides a powerful and useful tool.     

永夏矿区地层非采动沉陷分析

通过实验、实测和理论分析,研究了永夏矿区厚松散含水地层内部非采动沉陷原因,揭示了厚松散含水层地区开采沉陷特殊性的机理,对提高开采沉陷预测的精度具有重要意义。     

煤矿陷落柱槽波探查技术及应用

陷落柱是岩溶空顶塌陷的产物,也是影响矿井采掘衔接和安全生产的重要因素之一。为了提前查明陷落柱的赋存特征,避免工作面回采过程中无计划揭露陷落柱带来的人员伤亡和财产损失,针对典型矿井,制定标准煤岩样,展开室内试验分析,并选择合理的工程现场,展开槽波地震透射法和反射法勘探,最终,结合槽波速度法和能量法分析圈定陷落柱范围,通过探采成果对比研究该方法对陷落柱精准探查的适用性。结果表明:槽波透射法速度分析中,陷落柱的槽波速度与其裂隙发育情况和胶结程度密切相关,异常值难以准确界定;槽波透射法能量分析中,陷落柱的槽波振幅值衰减严重,可以依据衰减系数和相应计算方法,准确圈定陷落柱的发育范围;如果陷落柱与煤体交界面完好,与煤层夹角适合,槽波反射法速度分析可以准确划定陷落柱的边界。因此,槽波地震勘探对陷落柱构造的探测效果良好,能够有效指导矿井的安全生产。     

爆破地震振动危害及评价方法的探讨

本文分析了爆破地震振动特征及其对相关环境设施物造成危害的本质,总结了共有三种有效、实用的爆破地震振动评价方法,指出应当根据不同的爆破地震传播环境以及相关的不同结构特性来选择相应的振动评价参量和方法。     

基于最大值的岩层断裂监测机理与方法研究

研究由矿山开采引起的覆岩断裂,可探究地表沉陷的原因及覆岩断裂与地表沉陷的时空关系。从岩层断裂时诱发的微震现象入手,利用微地震定位原理,建立微震计算模型。在获得微波同时不考虑振幅、频率与能量的基础上,只要每个检波器能够检测到的是同一性质的最大值时刻,就可以实现岩体断裂（震源）的空间定位,从而利用最大值达到时刻来确定岩体断裂的即时位置,确定微震波速,进而研究地表沉陷的内部原因。     

山西矿山地质灾害分布特征研究

山西矿产资源丰富,矿山数量众多,长期的采矿活动给全省地质生态环境带来了严重破坏,造成了严重的矿山地质灾害。研究发现,山西矿山地质灾害以地裂缝和地面塌陷为主,崩塌和滑坡灾害主要以小型为主,地面塌陷以小型和中型为主,地裂缝以中型和大型为主。煤矿山、铝土矿山、铁矿山地质灾害均主要以地裂缝和地面塌陷为主,铜矿山地质灾害主要以崩塌为主。矿山地质灾害以小型和中型地质灾害为主,大型地质灾害以地裂缝为主,小型地质灾害以地面塌陷为主,中型地质灾害以地裂缝和地面塌陷为主。煤矿山和铝土矿山地质灾害均以小型地面塌陷和大型地裂缝为主,铁矿山地质灾害以小型地面塌陷为主,铜矿山地质灾害以小型崩塌为主。地裂缝和地面塌陷主要分布在晋城和阳泉矿区,滑坡灾害主要分布在离柳、西山、乡宁、汾西矿区,崩塌主要在大同、离柳矿区。     

矿震震波传播规律的三维模型及其应用

针对目前矿震震波的传播模型尚不完善这一问题,通过分析矿震产生的机理,对矿震进行分类。同时建立矿震发生的三维激振模型,进而导出矿震波的传播模型。通过在矿震监测系统的应用表明,该模型有效提高了震级计算和定位计算的精度。模型的建立解释了矿震发生的机理。     

Evolution of stress fields and induced seismicity in operating mines

The authors propose a new procedure for establishment of the space-time relationships between the quantity and energies of seismic events and the stress-strain state parameters using deterministic information on variation of geomechanical fields and the statistical analysis of the induced seismicity data. The new procedure has been verified under conditions of Tashtagol iron ore mine.     

煤矿开采地表沉陷预测及其防治研究

以陕西某矿4号开采煤层为研究对象,通过地质条件分析和地表移动变形现场观测,得出非充分采动条件下对地表的沉降规律,并通过FLAC^3D模拟进行验证。研究结果表明,仅有1个工作面开采时,地表下沉量很小,沉降系数为0.028,没有对地表的建筑物造成破坏;当2个工作面交替回采时,地表的沉降变形明显增大,沉降系数达到了0.15,属于非充分采动范围,不对地表建筑物造成破坏。开采工作面数量的增多不会增大地表的移动范围,使得地表下沉量和下沉速度显著增大,主要是受坚硬顶板的控制。当采深大于1.5 m以后,地表进入充分采动状态,地表建筑物将遭到破坏。研究结果阐明了煤矿工作面开采后的地表沉陷规律,也为相似地质条件矿井的地表沉降防治提供了参考。     

河南省煤矿塌陷地复垦模式研究

在调查河南省煤矿塌陷地实际情况的基础上,根据河南省煤矿塌陷地地形地貌特点和区域位置,以尽快恢复被破坏土地的原有生产能力为出发点,系统分析了煤矿塌陷地的特性,通过对不同塌陷地进行比较分析,研究提出了5种不同类型塌陷区的复垦模式和4种不同分区塌陷地的复垦模式。该研究为河南省矿区土地复垦工作的开展提供了科学依据,并可为全国其它矿区土地复垦工作提供借鉴。