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1.
Tong-En Mao Zhan-Po Liu Chang-Fang Xu Hong-Kui Zhang Su-Rong Yu Meng-Jing Lei 《地震学报(英文版)》1998,11(2):189-196
The 1° × 1° distribution map of crust-mantle structural ratio R for the lithosphere along the Longitudinal Seismic Belt of China has been compiled using computer based on the results of
geophysical prospecting by previous researchers, and the latest results by the present authors. Based on this map, an insight
into the structural features of the crust-mantle assemblage along the Longitudinal Seismic Belt has been gained, while their
relation to seismic activity and the distributions of geothermal flux and intracrustal high conductivity-low velocity layers,
as well as their tectonic effect to seismicity have been discussed.
Contribution No. 97A0079, Institute of Geophysics, State Seismological Bureau, China. 相似文献
2.
Jan Wiszniowski Nguyen Van Giang Beata Plesiewicz Grzegorz Lizurek Dinh Quoc Van Le Quang Khoi Stanisław Lasocki 《Acta Geophysica》2015,63(3):843-862
Song Tranh 2 hydropower plant and the reservoir containing backed up water are located in the Quang Nam province (Central Vietnam). The region experiences unusual seismic activity related to the reservoir impoundment, with earthquakes of magnitude up to 4.7. In result of cooperation between the Institute of Geophysics, Vietnam Academy of Sciences and Technology and the Institute of Geophysics, Polish Academy of Sciences a seismic network has been built to facilitate seismic monitoring of the Song Tranh 2 area. The network, operating since August 2013, consists of 10 seismic stations. Here we show that the network is sufficient for advanced data processing. The first results of monitoring of the earthquake activity in Song Tranh 2 area in the period between 2012 and 2014, especially the completeness of catalogs, study and comparisons between water level and the seismic activity suggest direct connection between reservoir exploitation and anthropogenic seismicity. 相似文献
3.
本义利用1979-1981年中国科学院地球物理研究所在随县-马鞍山所做的人工源地震探测的资料,采用二维射线追踪来拟合地震波的走时和振幅,取得了该地带的地壳与上地慢速度结构.结果表明,该地带地壳厚度为32-37km,莫霍面起伏变化显著.地壳速度的横向变化甚为强烈,地壳中部存在低速层.在巢湖以西宽数10km的范围内,地壳结构与其它地方明显不同,上地壳速度明显偏高,莫霍面上隆并有间断;在其两侧,明显可见有两条深断裂.结合其它地球物理场特征及大地构造概况,对结果进行分析,认为郯庐构造带南段被两条深断裂所夹,构造带宽度可达数10km,并在地质历史时期曾有过地幔物质上涌. 相似文献
4.
随县—马鞍山地带地壳与上地幔结构及郯庐构造带南段的某些特征 总被引：14，自引：2，他引：14
本义利用1979—1981年中国科学院地球物理研究所在随县—马鞍山所做的人工源地震探测的资料,采用二维射线追踪来拟合地震波的走时和振幅,取得了该地带的地壳与上地慢速度结构.结果表明,该地带地壳厚度为32—37km,莫霍面起伏变化显著.地壳速度的横向变化甚为强烈,地壳中部存在低速层.在巢湖以西宽数10km的范围内,地壳结构与其它地方明显不同,上地壳速度明显偏高,莫霍面上隆并有间断;在其两侧,明显可见有两条深断裂.结合其它地球物理场特征及大地构造概况,对结果进行分析,认为郯庐构造带南段被两条深断裂所夹,构造带宽度可达数10km,并在地质历史时期曾有过地幔物质上涌. 相似文献
5.
Summary A series of paired explosions in a salt mine near Winnfield, Louisiana, has been conducted to test a theory by Dr.A. L. Latter concerning seismic decoupling by underground cavities. The theory predicted a decoupling of about 100. Free-field and surface measurements from an explosion in either a 6-ft-or a 15-ft-radius spherical cavity were compared with similar measurements from a completely tamped explosion. Shot sizes were from 20 Ib up to a few tons. Surface measurements were made out to 100 km and covered the frequency range from 0.5 to 100 cps. The experiment confirmed that decoupling does occur. The actual decoupling factor as a function of frequency is presented and compared with theLatter theory.Presented at the international meeting of the International Union of Geodesy and Geophysics at Helsinki, July 27, 1960. 相似文献
6.
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
7.
（毛桐恩，姚家榴）Ｔｈｅｒｅｌａｔｉｏｎｓｈｉｐｂｅｔｗｅｅｎｃｒｕｓｔ－ｍａｎｔｌｅｓｔｒｕｃｔｕｒａｌｒａｔｉｏａｎｄｓｅｉｓｍｉｃａｃｔｉｖｉｔｙ￥Ｔｏｎｇ－ＥｎＭＡＯａｎｄＪｉａ－ＬｉｕＹＡＯ（ＩｎｓｔｉｔｕｔｅｏｆＧｅｏｐｈｙｓｉｃｓ，Ｓｔ... 相似文献
8.
2008年5月12日汶川8.0级地震发生后,地震科技工作者立即投入到震后应急救援、现场余震监测、灾害评估、地震机理研究、震情趋势判定和现场科学考察中。其中,中国地震局地球物理研究所青年专家在地震精定位、震源机制及数字化地震参数计算、震源破裂过程、地震灾区区划图编制、余震破坏影响范围确定、地震社会学分析与应用等方面发挥了重要作用。截止到2008年12月,研究所40岁以下科技人员在各种科研刊物上发表了SCI、EI文章就有10余篇,参加现场工作人员41人次。青年科技人员能够迅速投入到震后科技支撑工作中,得益于研究所平时对青年科技人员教育和培训工作的重视,本文对此进行了评估和讨论。 相似文献
9.
Ｒｅｌｏｃａｔｉｏｎ ｏｆ ｍｉｃｒｏｅａｒｔｈｑｕａｋｅｓ ｉｎ Ｂｅｉｊｉｎｇ ａｎｄ ｉｔｓ ｎｏｒｔｈｗｅｓｔ ｎｅｉｇｈｂｏｕｒｉｎｇ ａｒｅａＳｕ－ＹｕｎＷＡＮＧ（汪素云）；Ｚｈｏｎｇ－ＨｕａｉＸＵ（许忠淮）；Ｙａｎ－ＸｉａｎｇＹＵ（俞言... 相似文献
10.
Claudio Ebblin 《Pure and Applied Geophysics》1986,124(4-5):897-917
Three Cambridge wire strainmeters and a pair of horizontal-pendulum tiltmeters operate since 1978, in a cave in the northern Friuli seismic area. Straightforward considerations, based on the principles of continuum mechanics, permit a first estimate of the secular and seasonal variations of the cave strain rate tensor, under the assumption of homogeneous, constant-volume strain, together with an analysis of the effects on the tensor components of particular tiltmeter installation sites with respect to the orientation of both the strainmeters plane and the principal axes.The area lies at the complex intersection of NW-SE Dinaric rock structures and E-W Alpine ones. The latest period of strong seismic activity there started in mid-1976. The fault-plane solutions of the main shock revealed a direction of maximum compression perpendicular to the Alpine trend, but later in 1976 and 1977 such a direction seemed to have changed, having become perpendicular to the Dinaric trend.A plain analysis of the strain gauge data show that, from 1978 to 1981, the maximum shortening secular strain changed progressively from a SW bearing to a SSE one or even SE one. Hence, it would appear that by 1981 the direction of maximum compression had become Alpine again.In the same time interval, the principal axes of the five observed yearly seasonal strain rates maintained a Dinaric orientation similar to that of the geological structures around the cave.Finally the orientations of the secular strain acceleration principal axes appear to be nearly coaxial with those of the stress obtained from various 1977 fault-plane solutions, the compressional stress corresponding to extensional accelerations andvice-versa. Such observation suggests that the modifications of secular strain rates are related to the stress release connected with the seismic activity. 相似文献
11.
The comparative observations of the tidal gravity in Three Gorges reservoir area, recorded with the LCR-ET20 gravimeter from Institute of Geodesy and Geophysics, Chinese Academy of Sciences and the DZW-9 gravimeter from Institute of Seismology, China Earthquake Administration, are introduced. High-accuracy tidal gravity pa-rameters in this area are obtained, and the scale factor of the DZW-9 gravimeter is also estimated at a value of ?(756.06±0.05)×10?8 m?s?2V?1. The observed residuals of the corresponding instruments are investigated. Nu-merical results indicate that the long-term drift of the DZW-9 gravimeter appears a linear characteristic, and the observed accuracy is of the same order comparing with that of the LCR-ET20 gravimeter. The results given in the paper can provide with an effective reference model of the tidal gravity correction to the ground based and space geodesy. 相似文献
12.
应用中国地震局地球物理研究所和蒙古科学院天体和地球物理研究中心合作编制的蒙古国及邻区M≥3.5的地震目录,研究了中蒙弧地区的地震活动性特征.结果表明,与中国大陆的“南北地震带”相对应,研究区地震总体分布大致以107°E为界,呈现西强东弱的特点,7级以上的强震集中于贝加尔湖、萨彦、阿尔泰以及天山地区,107°E以东,除纬度40°线附近（燕山地震带）地震较集中且强度大之外,其它地区地震稀少,强度也低.通过断层的野外调查和本地区震源机制解,进一步研究了该地区地震活动性特征的构造应力场及地球动力学成因.研究区大部份地震都是走滑型断层活动的地震.逆断层活动的地震主要分布于中国的天山地区和中蒙边境一带的阿尔泰山地区,正断层活动的地震主要分布于俄罗斯的贝加尔湖裂谷带,走滑兼倾滑断层活动的地震主要分布在研究区域的西部地区.研究区域内的大部份地区主压应力轴（P）的倾角都小于30°,为水平或近水平的构造应力场,自西向东主压应力轴的走向从近南-北方向逐渐转为北东-南西方向.断层的野外调查、震源机制解和区域构造应力场的方向表明,中蒙弧地区主要来自西南面的印度洋板块向北偏东方向的碰撞挤压,通过青藏高原传递到本区,来自东面太平洋板块的影响已较微弱,这是研究区地震活动西强东弱、8级以上强震都发生在西部的主要原因. 相似文献
13.
The influence of hot mantle intrusive body on tectonic stress field and displacement field of Dabie orogenic belt have been
analyzed by means of finite element method. Numerical simulations show that the intrusion of hot mantle material leads to
an extensional stress state in the upper crust of central Dabie mountains, while compressive stress state appears on both
sides of orogenic belt under the action of horizontal compression from Yangtze craton. This is in accordance with the actual
faulting tectonics in this area. Possible evolution trend in transition area is discussed, too.
Contribution No. 99FE2020, Institute of Geophysics, China Seismological Bureau. 相似文献
14.
IntroductionThe present-day digital seismic observation technique provides us a large amount of accurate seismic records of high-precision, wide-band, and large dynamic range and conditions for higher-solution and higher-speed discrimination of earthquakes. But the problem we face is how to use the modern theory and method for digital signal processing in fast and precise extraction of the characteristic parameters from the large amount of digital seismic records. A basis or the important prob… 相似文献
15.
Using the double-difference earthquake location algorithm, the deterministic method (PTD method) and the CAP seismic moment tensor inversion method, the paper selects the primary waveform data of 78 earthquakes recorded by the "China Earthquake Science Array Probe Project in the Northern Part of North South Seismic Belt", the "China Earthquake Scientific Exploration Array Data Center" of Institute of Geophysics, China Earthquake Administration, and the Inner Mongolia Digital Seismic Network to calculate the focal depths of the mainshock and the seismic sequence of the MS5.8 Alxa Left Banner earthquake in Inner Mongolia. The results show that the focal depth of the main shock is 20.6km, determined by the double-difference earthquake location method, 18.1km by the PTD method, and 19.2km by the CAP method. The focal depth of the earthquake sequence calculated by the double-difference location method is larger. The deterministic method (PTD method) and double-difference location method are the methods that fit the tectonic characteristics of the seismic source area, and the CAP method is suitable for larger earthquakes. 相似文献
16.
Hard coal mining in the area of the Bytom Syncline (Upper Silesia Coal Basin, Poland) has been associated with the occurrence of high-energy seismic events (up to 109 J; local magnitude up to 4.0), which have been recorded by the local mining seismological network and regional seismological network. It has been noticed that the strongest seismic events occur when the mine longwall alignments coincide with the syncline axis. Data recorded by the improved local seismic network in the Bobrek Mine allow the estimation of the depths of the events’ hypocentres during excavation of longwall panel 3 as it approached the syncline axis. The recorded data were also used to estimate the location of the rupture surface and stress distribution in the seismic focus region. It was concluded that tectonic stresses, particularly horizontal stress components, are essential in the distribution of seismic tremors resulting from reverse faulting. The stresses induced by mining activity are only triggering tectonic deformations. The hypocentres of the strongest seismic events during mining of longwall panel 3/503 were located 300–800 m deeper than the level of coal seam 503. 相似文献
17.
According to the fracture mechanics rupture model of earthquakes put forward by us, several equations to compute tectonic
ambient shear stress value τ0 have been derived [equations (1), (2), (3), (5)]. τ0 values for intermediate and small earthquakes occurred in Chinese mainland and Southern California have been calculated by
use of these equations. The results demonstrate that the level and distribution of τ0 are closely related to the location where large earthquakes will occur, i.e. the region with higher level of τ0 will be prone to occur large earthquakes and the region with lower level will usually occur small earthquakes. According
to the spatial distribution of τ0, the seismic hazard regions or the potential earthquake source regions can in some degree be determined. According to the
variation of τ0 with time, the large earthquake occurrence time can be roughly estimated. According to the distribution of τ0 in Southern California and variation with time, three high stress level regions are determined, one (Goldfield area) of them
is the present seismic hazard region.
Contribution No. 98A02023, Institute of Geophysics, State Seismological Bureau, China 相似文献
18.
Stress field and seismicity in the Indian shield: Effects of the collision between India and Eurasia
Intraplate stresses and intraplate seismicity in the Indian subcontinent are strongly affected by the continued convergence between India and Eurasia. The mean orientation of the maximum horizontal compression in the Indian subcontinent is subparallel to the direction of the ridge push at the plate boundary as well as to the direction of compression expected to arise from the net resistive forces at the Himalayan collision zone, indicating that the intraplate stresses in the subcontinent, including the shield area, are caused by plate tectonic processes. Spatial distribution of historic and instrumentally recorded earthquakes indicate that the seismic activity is mostly confined to linear belts while the remaining large area of the shield is stable. The available conventional heat flow data and other indicators of heat flow suggest hotter geotherms in the linear belts, leading to amplification of stresses in the upper brittle crust. Many of the faults in these linear belts, which happen to be 200–80 m.y. old, are being reactivated either in a strike-slip or thrust-faulting mode. The reactivation mechanisms have been analyzed by taking into consideration the amplification of stresses, pore pressures, geological history of the faults and their orientation with respect to the contemporaneous stress field. The seismicity of the Indian shield is explained in terms of these reactivation mechanisms. 相似文献
19.
华北地区中东部涵盖北京、天津以及即将建设的雄安新区等大型城市,区内发育了张渤地震带等多条大型活动断裂,地震活动性较强,历史上发生过多次6级以上地震.本文利用Fan小波的布格重力异常一致性方法研究该区的岩石圈有效弹性厚度和均衡调整初始加载比分布,同时基于均衡调整方法计算该区垂向构造应力分布,并将以上结果与历史地震活动进行统计分析.岩石圈挠曲分析表明,华北地区中东部的岩石圈有效弹性厚度为10~65 km,分布特征为自东南向西北逐渐减小.均衡调整初始加载比为0.5~0.8,表明现今的岩石圈挠曲状态主要由莫霍面加载形成.该区地壳承载的垂向构造应力约为-20~20 MPa,中西部地区垂向构造应力向上,东北和西南地区向下.统计分析结果显示,华北地区中东部的地震活动性随着岩石圈有效弹性厚度和均衡调整初始加载比的增加而减弱,垂向构造应力零值区域地震活动性较弱.雄安新区的岩石圈有效弹性厚度大约为15 km,均衡调整初始加载比为0.5~0.6,垂向构造应力为15~20 MPa,岩石圈参数对应的地震活动性较强,相关结果对于新区建设具有一定参考价值. 相似文献
20.
On the basis of the assumption that ω^2 model accords with source displacement spectra, we have obtained the mathematical expressions for calculating apparent stresses of moderate-small shocks from low-frequency flat level and comer frequency. By using digital seismic records, apparent stress values are calculated for 823 moderate-small shocks of 4 earthquake series in Yunnan area following corrections for instrument response, propagation influence and site effect. The results show that for the 4 earthquake series in Yunnan area, apparent stress hints precursory information, which means that if a moderate-small shock occurs with apparent stress larger than 1 MPa in an earthquake series, a moderate-strong earthquake will occur afterwards; and if there is not moderate-small shock with apparent stress larger than 1 MPa after a moderate-strong event in an earthquake series, strong aftershock will not occur. The research also indicates that the average apparent stress value is 0.8 MPa in Yunnan area, therefore, apparent stress is not obviously related to seismic magnitude. 相似文献