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1.
Induced seismicity in large-scale mining in the kola peninsula and monitoring to reveal informative precursors 总被引：1，自引：0，他引：1
Large volumes of rock mass, mined-out and moved within these deposits, resulted in irreversible changes in the geodynamic regime in the upper earth's crust of the adjacent territory. These changes manifest themselves in a more frequent occurrence of such intensive dynamic phenomena as tectonic rock bursts due to fault movement adjacent to the area which is mined-out and man-made earthquakes which sharply decrease mining safety and result in great material losses.To develop the prediction techniques of such phenomena, a monitoring system is created, based on the program of the Kola Complex of geodynamic measuring stations. Most of this system is realized in the region of the Khibiny apatite mines. The system provides regional seismological monitoring, local prediction of seismicity in separate areas of a rock mass and, determination of stress and strain in rock masses, local geophysical monitoring over the state of rocks in a rock mass as well as physical and mathematical modelling of geodynamic processes in the upper earth's crust.The investigations have resulted in the distinguishing of some regularities in manifestations of induced seismicity and tectonic rock bursts and in the determination of strain precursors of intensive seismic events in the Khibiny mines.The mechanism is provided by the induced seismicity which resulted from the anthropogenic impact on the geological medium. A geodynamic monitoring complex is described, which is used to reveal the precursors of powerful seismic eventsin situ, and monitoring results are shown, obtained in the Kola Complex of geodynamic stations. Methods of preventing tectonic rock bursts and induced earthquakes are presented. 相似文献
2.
Results of seismological observations in the western Kaliningrad region and in the Baltic Sea water area 总被引：1，自引：1，他引：0
S. A. Kovachev 《Izvestiya Physics of the Solid Earth》2008,44(9):706-716
In 2006–2007, researchers of the IO RAS conducted seismological observations in the Baltic Sea and western Kaliningrad region with the use of ocean-bottom and land-based autonomous seismic stations. According to maps of general seismic zoning of the territory of Russia, the Kaliningrad region is aseismic. However, a series of seismic phenomena with magnitudes of about 5 and sources located near the Bay of Gdansk coast occurred here in September 2004. The total duration of the IO RAS seismological observations in five areas of the region under investigation was more than 200 days. The analysis of seismic records of the IO RAS network located sources of two local weak earthquakes with magnitudes M L = 3.4–3.5, which indicates that the seismic process in the western part of the Kaliningrad region continues and the region is far from being seismically stable. 相似文献
3.
Seismicity of the southern Siberian platform: Spatiotemporal characteristics and genesis 总被引：1，自引：0，他引：1
Analysis of instrumental data on earthquakes of 1960–2005 in the Irkutsk amphitheater shows that the majority of the earthquakes form a wide (150–300 km) band of diffuse seismicity along the marginal suture of the Siberian platform. In accordance with established regular spatiotemporal patterns of the distribution of earthquakes, this band belongs to the Sayan-Baikal seismic belt, associated with the destruction process at the boundary of large lithospheric blocks. The band is located on the northern periphery of the belt and, the deformable substrate being highly monolithic, this sharply weakens the seismicity within the band. Because of the tectonic origin of earthquakes in such a vast platform territory, undoubted evidence for induced seismicity around the Angara cascade reservoirs, and the intense economic development of the region, the problem of seismic hazard in the southern Siberian platform should be regarded as one of the most significant objects of geodynamic research. 相似文献
4.
A. A. Nikonov 《Izvestiya Physics of the Solid Earth》2008,44(11):915-926
The seismic situation in the SE Baltic region that existed during the period 1990–2006, including the unexpectedly strong Kaliningrad earthquakes of 2004, is analyzed. The spatiotemporal variation of seismic events in the region is examined on the basis of a newly compiled catalog of tectonic earthquakes. The analysis revealed outbursts of seismic activity in 1995 and 2004, structurization of the distribution of shocks, and their southward migration. The distribution of hot springs that arose in 2002–2004 is analyzed in relation to seismological data. The seismic process and thermal anomalies are shown to be geodynamically controlled, which provided constraints on the nucleation process and focal mechanism of the Kaliningrad earthquakes. The region, located in the western East European platform, should be regarded as seismically rather active. 相似文献
5.
--In this comprehensive study of seismicity and seismotectonics of the peninsular Indian shield region, seismic data of regional earthquakes spanning two decades (1978-1997), obtained at Gauribidanur seismic array (India) and integrated where necessary with data from other seismological stations in the region, have been analyzed in detail. With a slow rate of stress accumulation, the shield is found to have low to moderate seismicity that takes into account a couple of earthquakes of magnitude slightly larger than 6. The frequency-magnitude analysis of the data set gives a b value of 1.18. The spatio-temporal pattern of occurrences of the earthquakes combined with their magnitude and seismic energy distribution is consistent with the view that the peninsular seismicity is low to moderate and episodic in nature. Regions of moderate seismicity and its low-grade counterpart constituted by microearthquakes (magnitude less than 3), appear correlated to the areas traversed by known geologic faults and subfaults, shear zones, and other such tectonic features. Microearthquakes represent about two-thirds of the total regional seismic events during the past two decades. 相似文献
6.
Summary The paper is intended as a contribution to the quantitative analysis of travel-time curves of seismic events recorded in the Ostrava-Karviná District (OKD). The input data represent a set of 2621 seismic events, recorded by the local seismological network of 26 mine stations DSLA and a regional diagnostic polygon consisting of five surface Lennartz stations. All the events were processed automatically in the Operational Seismological Centre of the Czechoslovak Army Mine in Karviná and stored in the seismological data base. The results are presented in the form of graphs of arrival times versus distance for the whole OKD, for two mines and one tectonic block.Travel-time curves of direct P and S waves, as well as of reflected and refracted waves are given. The direct P and S waves propagate well practically throughout the whole region studied, but their apparent velocities of propagation are affected by the properties of the rock medium.As a result of the complicated geological conditions, the recorded wave image is quite complicated. Methods of mathematical modelling, using kinematic and dynamic parameters of seismic waves, will have to be applied to identify the separate wave groups uniquely. 相似文献
7.
The work continues the study of interrelations between strong flare-induced magnetic storms and variations of seismicity. Using data on the time dependences of the parameters of seismic noise (average level and root mean squared (RMS)), recorded by stations of the KNET seismic network during monitoring of the territory of Bishkek geodynamic site (North Tien Shan). The presented results indicate the high sensitivity of the seismic noise in the frequency range of 10–20 Hz to external and, in particular, electromagnetic effects in comparison to the seismic activity. We noted the manifestations of the effects of magnetic storms that occurred after strong and super-strong solar flares in 2000–2006. These were short-term increases in the RMS of seismic noise, preceding changes in the accumulation rate of the number of events. The obtained results agree with conclusions about the interrelation between seismicity and magnetic storms. A model is suggested to describe one of the possible mechanisms by which the electromagnetic pulses and the currents induced by them in a medium devoid of piezoelectric properties influence the seismic process. 相似文献
8.
9.
利用四川数字地震台网和流动地震台站在芦山MS7.0地震震后(2013年4月20日—6月23日)记录到的2026次区域地震事件的28188条P波到时资料,采用地震层析成像方法反演得到了芦山地震震源区及其周边区域中上地壳P波三维速度结构. 结果表明,浅部地壳的P波速度异常分布特征与地表地质构造、 地形和岩性密切相关,即成都断陷盆地表现出与第四纪沉积有关的低速异常区;犍为、 乐山一带的川中微升区和川青块体龙门山以西的邻近地带均表现为与构造抬升有关的高速异常;宝兴、 康定附近分布的基性火山岩及火山碎屑岩均呈局部高速异常分布. 芦山地震震源位于高低速异常分界线附近且偏向高速体一侧,其下方存在明显的低速异常分布,可能与流体的存在有关. 流体的作用导致中上地壳内部发震层的弱化,使孕震断层易于破裂,可能对芦山地震起到了触发作用. 芦山地震与汶川地震两次地震的余震密集区相距50 km,这50 km地震空区震源体的深度范围附近目前正处于高速异常区内,加之龙门山断裂带西南段又具有比较典型的断错地貌发育,使得该段地震空区(大邑—邛崃活动断裂破裂空段)现在所处的深浅部构造环境变得复杂,其潜在的地震危险性仍值得进一步关注. 相似文献
10.
We investigated the seismicity in the aftershock area of a great earthquake occurring on April 20, 2006 (21:04 LT) in the
area of the Koryak Autonomous Okrug. This analysis of the aftershock process was based on a complete catalog of the earthquakes
that were recorded during April–May 2006 by the regional network of seismic stations operated by the Kamchatka Branch of the
Geophysical Service of the Russian Academy of Sciences. We also made use of a catalog of low magnitude events for May 2–17
as recorded by a mobile seismic network deployed in the rupture zone. We provide a review of seismicity for the Koryak Upland
for the period of instrumental observations in the 20th and early 21st centuries. 相似文献
11.
Marcin Polkowski Beata Plesiewicz Jan Wiszniowski Monika Wilde-Piórko Passeq Working Group 《Acta Geophysica》2016,64(6):2092-2113
PASSEQ 2006–2008 (Passive Seismic Experiment in TESZ; Wilde-Piórko et al. 2008) was the biggest passive seismic experiment carried out so far in the area of Central Europe (Poland, Germany, the Czech Republic and Lithuania). 196 seismic stations (including 49 broadband seismometers) worked simultaneously for over two years. During the experiment, multiple types of data recorders and seismometers were used, making the analysis more complex and time consuming. The dataset was unified and repaired to start the detection of local seismic events. Two different approaches for detection were applied for stations located in Poland. The first one used standard STA/LTA triggers (Carl Johnson’s STA/LTA algorithm) and grid search to classify and locate the events. The result was manually verified. The second approach used Real Time Recurrent Network (RTRN) detection (Wiszniowski et al. 2014). Both methods gave similar results, showing four previously unknown seismic events located in the Gulf of Gdańsk area, situated in the southern Baltic Sea. In this paper we discuss both detection methods with their pros and cons (accuracy, efficiency, manual work required, scalability). We also show details of all detected and previously unknown events in the discussed area. 相似文献
12.
Mario Octavio Cotilla Rodriguez 《Journal of Seismology》1998,2(4):323-335
The seismicity of Cuba is briefly presented together with a few fundamental neotectonic elements of the adjacent Caribbean region. The Cuban seismicity catalogue has been extended back to 1528 and it shows that the largest earthquakes occurred in 1766 and 1852 (I = IX MSK). Two types of seismicity (intraplate and interplate) can be distinguished in Cuba. Western and Eastern Seismotectonic Units correspond to intraplate type and the Southeastern Seismotectonic Unit to interplate type. Western Cuba is characterized by a low frequency of earthquake occurrence. Distribution of epicenters is not regular and the most important events mainly concentrate along two regional active fault system (Nortecubana and Surcubana). Due to the lack of seismic stations in this region, the characterization of seismicity is frequently done on the grounds of historical data available from 1693. The main seismogenic source for Cuba is the Bartlett-Cayman fault system, but inland there are other active structures. Some issues about historical and present day Cuban seismological research are also showed. 相似文献
13.
2002年6月以来,长白山天池火山区的地震活动明显增加. 本文利用2002年夏季布设在长白山天池火山区15套宽频带流动地震台站的记录资料,对天池火山区的地震活动进行了研究. 地震观测结果表明,2002年夏季长白山天池火山日平均地震发生频次超过30次. 地震主要位于长白山天池西南部和东北部两个区域,震源深度较浅,离地表的深度一般小于5km. 天池西南部和东北部的地震,b值存在较大的差异. 火山区地震记录的频谱分析和时频分析结果表明,这些地震主要为火山构造型地震. HSZ和DZD等台站地震记录中丰富的低频成分,可能与台站附近的局部介质或断层带有关. 我们认为2002年夏季频繁发生的地震和小震震群活动是由火山深部活动诱发的局部断裂活动引起. 相似文献
14.
Summary The western part of the Bohemian Massif located between two tectonic units, the Moldanubian and the Saxo-Thuringian, is characterized by the re-occurrence of earthquake swarms. The focal region for these swarms includes the territory of West Bohemia and the adjacent territory of SE Saxony and NE Bavaria. During the most recent swarm in December 1985 – January 1986, more than 8000 small earthquakes were recorded; the two largest earthquakes with local magnitudes (ML) of 4·6 and 4·1. This paper presents a summary of the seismic energy release in space and time for the western part of the Bohemian Massif, based on seismic observations of permanent seismic stations established in West Bohemia since 1986. It was found out that microearthquake activity, mostly of a swarm-like character, persisted between two macroseismically observed swarms. The foci of the microearthquakes predominantly cluster in six main epicentral zones, four of which are located in West Bohemia or in its immediate vicinity in Saxony. The remaining two are in Saxony and in Bavaria. The four epicentral zones in West Bohemia were studied in detail. It was found that the individual zones differ in size, in depth of hypocentres, in geometry, as well as in temporal activity. Moreover, it was found that the seismicity in the most active epicentral zone is closely related to the system of principal tectonic faults referred to as the Kruné Hory fault and the Mariánské Lázn fault. 相似文献
15.
Fine structure of Pn velocity beneath Sichuan-Yunnan region 总被引：3，自引：0，他引：3
We use 23298 Pn arrival-time data from Chinese national and provincial earthquake bulletins to invert fine structure of Pn velocity and anisotropy at the top of the mantle beneath the Sichuan-Yunnan and its adjacent region. The results suggest that the Pn velocity in this region shows significant lateral variation; the Pn velocity varies from 7.7 to 8.3 km/s. The Pn-velocity variation correlates well with the tectonic activity and heat flow of the region. Low Pn velocity is observed in southwest Yunnan , Tengchong volcano area, and the Panxi tectonic area. These areas have very active seismicity and tectonic activity with high surface heat flow. On the other hand, high Pn velocity is observed in some stable regions, such as the central region of the Yangtze Platform; the most pronounced high velocity area is located in the Sichuan Basin, south of Chengdu. Pn anisotropy shows a complex pattern of regional deformation. The Pn fast direction shows a prominent clockwise rotation pattern from east of the Tibetan block to the Sichuan-Yunnan diamond block to southwest Yunnan, which may be related to southeastward escape of the Tibetan Plateau material due to the collision of the Indian Plate to the Eurasia Plate. Thus there appears to be strong correlation between the crustal deformation and the upper mantle structure in the region. The delay times of events and stations show that the crust thickness decreases from the Tibetan Plateau to eastern China, which is consistent with the results from deep seismic sounding. 相似文献
16.
水库诱发地震与构造地震震源参数特征差异性研究——以龙滩水库为例 总被引：8，自引：0，他引：8
首先讨论龙滩库区水库蓄水与地震活动之间的关系,发现龙滩水库诱发地震特征十分明显,地震共分5丛呈丛集分布.利用库区架设的24个固定和流动台站记录的数字记录资料,在研究得到龙滩库区非弹性衰减和台站场地响应的基础上,精确测定得到了该地区总共1616个ML≥0.1级地震的震源参数,比较了水库诱发地震与构造地震震源参数特征的差异,得到了以下主要结论:1)龙滩水库地震活动与水库蓄水关系密切,不同蓄水阶段5丛的地震活动状态不同,局部断裂构造发育以及岩石透水性能影响着地震活动对蓄水过程的响应.2)龙滩水库诱发地震的地震矩M0随震级ML的增大而增大,两者之间存在较好的线性关系,统计关系为LogM0=1.07 ML+10.17.应力降与地震大小之间的关系和Nuttli的板内地震为增加应力降(ISD)模型的结果比较吻合,统计关系为LogΔσ=0.71 ML-2.89.3)龙滩水库地区地震辐射能量和地震视应力均随震级的增大而增大,后者意味着大地震是比小地震更高效率的地震能量辐射体.4)总体上不同丛地震应力降水平存在差异.地震应力降空间分布上与库水深度有较好的一致性,即库水深的区域应力降水平高.5)与同震级的构造地震相比,水库诱发地震的应力降值比前者明显偏低,大约小10倍.这可能是由于水库蓄水造成地下介质孔隙压力增大或者水的润滑作用,从而导致在一个比较低的构造应力情况下发生水库诱发地震. 相似文献
17.
选取2010年1月至2020年8月期间甘肃区域测震台网记录的兰州市周边地区三分向宽频带数字波形资料,采用震中位置空间分布、波形特征及傅里叶频谱特征对比等多种方法相结合,分析兰州市红古区非天然地震活动的特性。结果显示:该区临近测震台记录的大量地震事件波形特征和傅里叶频谱特征与其他区域地震存在显著差异,符合非天然地震的典型震相特征,且空间分布密集、震级较大,初步分析与该区矿产资源开发活动密切相关。对红古区非天然地震特征的研究有助于台网工作人员快速、准确的判别兰州周边地震类型,同时对兰州市地震灾害风险评估与防治也具有积极的参考价值。 相似文献
18.
On May 2, 1993 more than 200 seismic events from an underground mine in Tyrol/Austria were recorded with short-period seismometers of a local seismic network which was introduced in the late 1980s to monitor the tectonic seismicity in Tyrol in greater detail. The cause of this series of mining-associated events has become the subject of intensive investigations — as it was associated with a subsidence affecting an area of 10.000 m2. Underground observations revealed a number of discontinuities along which the rock mass was able to move. Seismic recordings of the close-by seismic stations revealed two types of mechanisms: One mechanism seems to be associated with pure block-sliding along several discontinuities, while other signals indicate additional collapse. The consideration and combination of several seismological principles made possible the construction of a model of the mine collapse. 相似文献
19.
Seismic data collected at four volcanoes in Central America during 1973 and 1974 indicate three sources of seismicity: regional
earthquakes with hypocentral distances greater than 80 km, earthquakes within 40 km of each volcano, and seismic activity
originating at the volcanoes due to eruptive processes. Regional earthquakes generated by the underthrusting and subduction
of the Cocos Plate beneath the Caribbean Plate are the most prominent seismic feature in Central America. Earthquakes in the
vicinity of the volcanoes occur on faults that appear to be related to volcano formation. Faulting near Fuego and Pacaya volcanoes
in Guatemala is more complex due to motion on a major E-W striking transform plate boundary 40 km north of the volcanoes.
Volcanic activity produces different kinds of seismic signatures. Shallow tectonic or A-type events originate on nearby faults
and occur both singly and in swarms. There are typically from 0 to 6 A-type events per day withb value of about 1.3. At very shallow depths beneath Pacaya, Izalco, and San Cristobal large numbers of low-frequency or B-type
events are recorded with predominant frequencies between 2.5 and 4.5 Hz and withb values of 1.7 to 2.9. The relative number of B-type events appears to be related to the eruptive states of the volcanoes;
the more active volcanoes have higher levels of seismicity. At Fuego Volcano, however, low-frequency events have unusually
long codas and appear to be similar to tremor. High-amplitude volcanic tremor is recorded at Fuego, Pacaya, and San Cristobal
during eruptive periods. Large explosion earthquakes at Fuego are well recorded at five stations and yield information on
near-surface seismic wave velocities (α=3.0±0.2 km/sec.). 相似文献
20.
The seismicity of the Mediterranean, compiled by the Euro-Mediterranean Seismological Centre (EMSC), is presented for the period 1998–2010. The data set contains earthquakes recorded by more than 3000 stations operated by 78 networks. The Euro-Med Bulletin (EMB) provides parametric information for 273,000 tectonic events. The location resolution is characterised by a constant improvement over the years made possible by gathering steadily increasing data contribution. Dedicated collaboration with the network operators through regular discussion and interaction allow proper review of input and output information.In addition to natural events, seismic networks report data related to nontectonic activity. Discrimination is a crucial step in the production of seismicity catalogues to provide accurate information used for seismic hazard assessment. Over 13 years, 62,000 artificial events are characterised, mostly located in the vicinity of the largest mine and quarry areas of the region. While a large amount of man-related seismic activity is properly described, we show that through statistical analysis, discrimination in the EMB can still be improved. This is especially useful to scan past data, when routine discrimination was usually not performed by local networks.Seismicity catalogues are also useful for integrated access data portal to diverse and distributed seismological products as multi-disciplinary approaches of seismology is necessary. It leads us to propose and develop an e-Bulletin where the scientists could access all type of seismological and engineering products (from strong motion or broad band waveforms to macroseismic analysis) by simply connecting to a single event dedicated web page. 相似文献