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Analysis of spatial distribution of mining tremors occurring in Rudna copper mine (Poland) 总被引：1，自引：0，他引：1
Maria Kozłowska 《Acta Geophysica》2013,61(5):1156-1169
The distribution of mining tremors is strictly related to the exploitation progress of mining works and, consequently, to the local stress field. In case the distribution is known, it is possible to determine future area of intensive seismicity in exploited mining panel. In the paper, an analysis of working face-to-tremor distance for Rudna copper mine in Poland is presented. In order to develop a spatial model of tremors’ occurrence in the exploited mine, the seismicity of four mining sections in the five-month period was investigated and the tremors’ distribution was obtained. It was compared with the spatial distribution of tremors in coal mines found in the literature. The results show that the places where tremors mostly occur — the vicinity of the face, in front of it — coincide with the high-stress area predicted by literature models. The obtained results help to predict the future seismic zone connected with planned mining section, which can be used in seismic hazard analysis. 相似文献
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Mark S. Bebbington David S. Harte Steven C. Jaumé 《Pure and Applied Geophysics》2010,167(6-7):801-818
Forecasts of future earthquake hazard in the San Francisco Bay region (SFBR) are dependent on the distribution used for the possible magnitude of future events. Based on the limited observed data, it is not possible to statistically distinguish between many distributions with very different tail behavior. These include the modified and truncated Gutenberg–Richter distributions, and a composite distribution assembled by the Working Group on California Earthquake Probabilities. There is consequent ambiguity in the estimated probability of very large, and hence damaging, events. A related question is whether the energy released in earthquakes is a small or large proportion of the stored energy in the crust, corresponding loosely to the ideas of self-organized criticality, and intermittent criticality, respectively. However, the SFBR has experienced three observed accelerating moment release (AMR) cycles, terminating in the 1868 Hayward, 1906 San Andreas and 1989 Loma Prieta events. A simple stochastic model based on elastic rebound has been shown to be capable of producing repeated AMR cycles in large synthetic catalogs. We propose that such catalogs can provide the basis of a test of a given magnitude distribution, via comparisons between the AMR properties of the real and synthetic data. Our results show that the truncated Gutenberg–Richter distribution produces AMR behavior closest to the observed AMR behavior. The proviso is that the magnitude parameters b and m max are such that a sequence of large events that suppresses activity for several centuries is unlikely to occur. Repeated simulation from the stochastic model using such distributions produces 30-year hazard estimates at various magnitudes, which are compared with the estimates from the 2003 Working Group on California Earthquake Probabilities. 相似文献
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A. Ya. Sidorin 《Seismic Instruments》2012,48(2):196-207
The diurnal periodicity of seismic events from three earthquake catalogs of Fennoscandia and Turkey is studied. The shape
of diurnal distribution of seismic events in all the catalogs under investigation is similar to the unordinary diurnal periodicity
of earthquakes described in previous papers. The principal feature of the diurnal periodicity of seismic events revealed in
this paper is a wide maximum of the events in the day time. The very reliable conclusion is made that it is caused by presence
of a great amount of quarry blasts in the catalogs. 相似文献
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Ralf Fritschen 《Pure and Applied Geophysics》2010,167(1-2):77-89
Coal mining in the Saar mine, Germany, is accompanied by mining-induced seismic events. Strong events occur only in certain areas of the mine, other areas exhibit almost no seismicity. Shear events occur simultaneously to non-shear events. The shear events occur in different depths but their epicenters do concentrate in bands. The strike of the bands coincides with the strike of larger regional faults in the area. The seismic events of the Saar mine show some characteristics which distinguish them from seismic events observed in other German coalfields. The Gutenberg–Richter relation, for example, does not hold for these events. Furthermore, radiated seismic energy and extracted coal volume are not correlated. In the Primsmulde field a strong seismic event was observed even before mining in that region started. The event was triggered just by driving roadways into the field. The shear events cannot be explained by the mining process alone. They are presumably induced in certain regions (bands) under tectonic load by an interaction of mining-induced and tectonic stresses. In February 2008, extraction in the Primsmulde field induced a seismic event of magnitude 4, which led to surface vibrations reaching 93 mm/s. After this event, the Primsmulde field had to be abandoned. Future extraction of the Saar mine will be restricted to some small areas not intersected by the event bands found in the Dilsburg Ost and Primsmulde fields. The Saar mine will close in 2011. 相似文献
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Guy Drijkoningen Guus van Noort Rob Arts Joren Bullen Jan Thorbecke 《Geophysical Prospecting》2012,60(2):239-254
This article addresses the question whether time‐lapse seismic reflection techniques can be used to follow and quantify the effects of solution salt mining. Specifically, the production of magnesium salts as mined in the north of the Netherlands is considered. The use of seismic time‐lapse techniques to follow such a production has not previously been investigated. For hydrocarbon production and CO2 storage, time‐lapse seismics are used to look at reservoir changes mainly caused by pressure and saturation changes in large reservoirs, while for solution mining salt is produced from caverns with a limited lateral extent, with much smaller production volumes and a fluid (brine) replacing a solid (magnesium salt). In our approach we start from the present situation of the mine and then study three different production scenarios, representing salt production both in vertical and lateral directions of the mine. The present situation and future scenarios have been transformed into subsurface models that were input to an elastic finite‐difference scheme to create synthetic seismic data. These data have been analysed and processed up to migrated seismic images, such that time‐lapse analyses of intermediate and final results could be done. From the analyses, it is found that both vertical and lateral production is visible well above the detection threshold in difference data, both at pre‐imaging and post‐imaging stages. In quantitative terms, an additional production of the mine of 6 m causes time‐shifts in the order of 2 ms (pre‐imaging) and 4 ms (post‐imaging) and amplitude changes of above 20% in the imaged sections. A laterally oriented production causes even larger amplitude changes at the edge of the cavern due to replacement of solid magnesium salt with brine introducing a large seismic contrast. Overall, our pre‐imaging and post‐imaging time‐lapse analysis indicates that the effects of solution salt mining can be observed and quantified on seismic data. The effects seem large enough to be observable in real seismic data containing noise. 相似文献
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M. V. Rodkin 《Izvestiya Physics of the Solid Earth》2011,47(11):966-973
The seismic process is usually treated as en example of development of self-organized criticality (SOC). However, implementation
mechanisms of SOC in the case of a seismic process have not been proposed. In the present work, the seismicity is modeled
as a sequence of a variety of stochastic episodes of avalanche-like relaxation of metastable subsystems. The model reproduces
all known empirical features inherent in the seismic process. The simulated pattern of behavior was revealed to agree with
the empirical regularities, which promotes an understanding of the physics of the seismic process. 相似文献
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地震目录资料是进行地震预测、地震危险性分析、地震活动性研究等地震学研究的基础资料.对地震目录资料的完整性可靠性分析是地震学研究的基础工作之一.近几十年来我国积累的大量的仪器地震记录,历史地震也在不断更新,为地震活动性研究提供了更为丰富的样本,因此有必要对新的地震目录进行完整性分析.本文采用了新的统计方法对我国仪器记录地震目录和历史破坏性地震目录进行了完整性分析.结果表明,对于仪器记录地震目录（M≥3.0）我国东部地区1975年后基本完整,西部地区1980年后基本完整.对于历史地震目录（M≥5.0）,东部地区1500年后基本完整,西部地区1950年后基本完整.考虑到华北地震区历史破坏性地震（M≥43/4）活动的时间非平稳性,我们采用突变点分析法研究了华北地震区历史破坏性地震目录的时间特征,得到了华北地震区地震活动周期性变化的突变点位置,并揭示了华北地震区历史破坏性地震目录完整起始时间约为公元1500年前后. 相似文献
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分析矿震破裂机制及微震的时空分布能够为矿区灾害评估提供更多的有效信息.本研究基于密集台阵观测对2019年11月12日辽宁抚顺2.4级矿震开展震源参数研究,震源机制解显示地震破裂包含明显的非双力偶分量,表现为体积压缩的塌陷机制,且震源深度较浅,最佳拟合矩心深度为0.6 km.同时,对11月3日—25日记录的连续地震波形开展微震扫描,新检测出324个微震事件(-0.5~2.0级),定位结果显示在M 2.4矿震发生前M>1.0级事件显著增多,且在矿震位置存在近南北向的微震条带分布,微震序列随时间向深部迁移(约1.5 km),暗示存在断层活化迹象.结合震源破裂机制,我们认为此次事件与矿区塌陷破裂密切相关,同时伴随先存断裂的剪切滑动.本研究表明,基于密集台阵观测的地震矩张量反演和微震检测研究,对判定矿震类型及防范矿区灾害具有重要的研究意义. 相似文献
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为满足深部矿区精细勘探的需求,研究适于矿区的震源技术至关重要.在便携式电磁驱动可控震源应用于矿区勘探过程中,单电磁驱动可控震源和组合震源分辨率不高.本文基于相控震源技术,采用有限差分方法,对二维地下空间不同介质模型的波场传播及地面接收点的响应进行数值模拟.模拟中,震源分别使用单震源、延时时间为0 ms及1.33 ms的9单元相控源,介质模型采用均匀、水平层状、不规则矿区模型,得到如下结果:均匀介质下相控震源激励定向地震波,0 ms、1.33 ms延时参数下相控源激发固定方向地震波,方向分别为90°和70.4°;层状介质模型下,0 ms参数下相控源产生的垂向地震波方向不随介质变化,1.33 ms相控源激励的定向地震波在不同介质中仍然具有方向性,但随波速变化,地震波发生偏折,地震波主波束方向由70.4°,依次变为68.5°,66.0°,63.7°,61.1°;不规则矿区模型下,1.33 ms相控源激发的地震波在首层介质内传播方向为70.4°,围岩内为65.4°,矿体内为63.1°.在水平层状矿区介质结构下,与单震源相比,1.33 ms和0 ms相控源令接收点信噪比分别提高了14.1 dB和10.2 dB;在不规则矿区模型下,1.33 ms和0 ms相控源较单震源令接收点信噪比提高了18.9 dB和14.9 dB.由此得到如下结论:相控源在复杂介质模型下仍具有激发定向地震波的能力,尽管波束方向在不同介质内会发生偏折;在多种延时参数下,相控源都具有改善接收数据信噪比的能力.综上所述,相控震源技术能有效提高矿集区的数据采集质量. 相似文献
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—A cellular automaton is used to study the relation between the structure of a regional fault network and the temporal and spatial patterns of regional seismicity. Automata in which the cell sizes form discrete fractal hierarchies are compared with those having a uniform cell size. Conservative models in which all the stress is transferred at each step of a cascade are compared with nonconservative ("lossy") models in which a specified fraction of the stress energy is lost from each step. Particular attention is given to the behavior of the system as it is driven toward the critical state by uniform external loading. All automata exhibit a scaling region at times close to the critical state in which the events become larger and energy release increases as a power-law of the time to the critical state. For the hierarchical fractal automata, this power-law behavior is often modulated by fluctuations that are periodic in the logarithm of the time to criticality. These fluctuations are enhanced in the nonconservative models, but are not robust. The degree to which they develop appears to depend on the particular distribution of stresses in the larger cells which varies from cycle to cycle. Once the critical state is reached, seismicity in the uniform conservative automaton remains random in time, space, and magnitude. Large events do not significantly perturb the stress distribution in the system. However, large events in the nonconservative uniform automaton and in the fractal systems produce large stress perturbations that move the system out of the critical state. The result is a seismic cycle in which a large event is followed by a shadow period of quiescence and then a new approach back toward the critical state. This seismic cycle does not depend on the fractal structure, but is a direct consequence of large-scale heterogeneity of these systems in which the size of the largest cell (or the size of the largest nonconservative event) is a significant fraction of the size of the network. In essence, seismic cycles in these models are boundary effects. The largest events tend to cluster in time and the rate of small events remains relatively constant throughout a cycle in agreement with observed seismicity. 相似文献
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R. P. Young D. A. Hutchins S. Talebi T. Chow S. Falls L. Farrell D. Jansen J. McGaughey J. Towers T. Urbancic 《Pure and Applied Geophysics》1989,129(3-4):647-659
The progress made on three phases of a research project, started in 1986 to investigate mining induced seismicity/rockburst phenomena using concurrent geotomographic imaging and microseismic monitoring techniques, is described. Phase I is the geotomographic software development and laboratory calibration trials. Phase II is the enhancement of traditional microseismic monitoring instrumentation with a waveform acquisition system, so that source mechanism studies can be carried out on mining induced seismic events. Phase III is the field trials of the hybrid technique which will be used to monitor changing rock mass physical properties, in response to mining. Preliminary results from all three phases are given, together with an outline of current and future research planned.Presented at the Fred Leighton Memorial Workshop on Mining Induced Seismicity, Montreal 1987. 相似文献
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Qazi Adnan Ahmad Guochen Wu Zong Zhaoyun Wu Jianlu Li Kun Du Tianwei Nasir Khan 《Geophysical Prospecting》2020,68(2):657-677
In exploration geophysics, the efforts to extract subsurface information from wave characteristics exceedingly depend on the construction of suitable rock physics model. Analysis of different rock physics models reveals that the strength and magnitude of attenuation and dispersion of propagating wave exceedingly depend on wave-induced fluid flow at multiple scales. In current work, a comprehensive analysis of wave attenuation and velocity dispersion is carried out at broad frequency range. Our methodology is based on Biot's poroelastic relations, by which variations in wave characteristics associated with wave-induced fluid flow due to the coexistence of three fluid phases in the pore volume is estimated. In contrast to the results of previous research, our results indicate the occurrence of two-time pore pressure relaxation phenomenon at the interface between fluids of disparate nature, that is, different bulk modulus, viscosity and density. Also, the obtained results are compatible with numerical results for the same 1D model which are accounted using Biot's poroelastic and quasi-static equation in frequency domain. Moreover, the effects of change in saturation of three-phase fluids were also computed which is the key task for geophysicist. The outcomes of our research reveal that pore pressure relaxation phenomenon significantly depends on the saturation of distinct fluids and the order of saturating fluids. It is also concluded that the change in the saturation of three-phase fluid significantly influences the characteristics of the seismic wave. The analysis of obtained results indicates that our proposed approach is a useful tool for quantification, identification and discrimination of different fluid phases. Moreover, our proposed approach improves the accuracy to predict dispersive behaviour of propagating wave at sub-seismic and seismic frequencies. 相似文献
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—We have found that the M w = 8.3 Kurile earthquake on October 4, 1994 followed an outstanding seismic quiescence starting 5–6 years before the mainshock near the ruptured area. We have analyzed three independent seismic catalogs Institute of Seismology and Volcanology, Hokkaido University (ISV), Japan Meteorological Agency (JMA) and International Seismology Center (ISC). In spite of selecting different magnitude bands and time windows all three catalogs presented the common feature of the seismic quiescence. This fact strongly suggests that the seismic quiescence should not be a man-made change but actually occurred. Moreover we have confirmed that the seismic quiescence was the most significant and the earthquake was the largest in the past twenty-five years in this region. Therefore we confidently interpret this seismic quiescence as an indication of a preparation process for the M w = 8.3 Kurile earthquake. 相似文献
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Seismological models for mining-induced seismic events 总被引：1，自引：0，他引：1
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As part of a larger multi-institutional seismic monitoring experiment during June–August 1984 in the eastern Wasatch Plateau, Utah, data from a subarray of 20 portable seismographs were used to investigate seismicity in the East Mountain area, an area of active underground coal mining and intense microseismicity. Eight stations of the subarray were concentrated on top of East Mountain, about 600 m above mine level, at an average spacing of 2 to 3 km. The primary objective was the accurate resolution of hypocenters and focal mechanisms for seismic events originating at submine levels. Data from high-resolution seismic reflection profiles and drill-hole sonic logs yielded a detailed velocity model. This model features a strong velocity gradient in the uppermost 1 km, which has a significant effect on takeoff angles for first-arrivingP-waves from shallow seismic events. Two hundred epicenters located with a precision of ±500 m cluster within an area about 5 km in diameter and show an evident spatial association with four sites of longwall mining during the study period. A special set of foci rigorously tested for focal-depth reliability indicates submine seismicity predominating within 500 m of mine level and extending at least to 1 km, and perhaps to 2 km, below mine level. Continuous monitoring for a 61-day period (June 15–August 15) bracketed a 16-day mining shutdown (July 7–22) during which significant seismicity, comparable to that observed before the shutdown, was observed. Ten focal mechanisms for seismic events originating at or down to 2 km below mine level nearly all imply reverse faulting, consistent with previous results and the inferred tectonic stress field. Enigmatic events recorded with all dilatational first motions can be fit with double-couple normal-faulting solutions if they in fact occurabove mine level, perhaps reflecting overburden subsidence. If these events are constrained to occur at mine level, their first-motion distributions are incompatible with a double-couple source mechanism. 相似文献
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Izvestiya, Physics of the Solid Earth - The information and seismic parameters gained from pre-instrumental earthquakes are essential to improve the seismic catalogs and hazard studies. The... 相似文献