共查询到19条相似文献,搜索用时 201 毫秒
1.
新疆克孜尔水库地震危险性预测研究 总被引:1,自引:0,他引:1
应用库区多项形变观测资料,对克孜尔水库蓄水后出现的形变异常及诱发水库地震的危险性进行了研究。结果认为:①穿过水库大坝的F2活断层在水后出现水平和垂直形变的特大异常变化主要是前期水库施工开挖土石方、填筑土石方及水库蓄水引起地面负荷变化的综合效应所致;②克孜尔水库虽然存在诱发水库地震的潜在因素,但从库容、坝高、F2活断层产状、地质构造背景、水地质条件、岩性以及世界各国发生水库 诱发地震的充分条件;③由库区各项形变观测资料分析表明,库区地壳形变已由施工-蓄水初期时的反向异常变化恢复到了施工蓄水前的正常变化状态,各种受力因素经过调整达到了新的平衡,已进入相对稳定的继承性运动期,因此今后因蓄水诱发水库地震的可能性不大。 相似文献
2.
隔河岩水库蓄水前即开始对穿越库区的主要断裂进行监测,并设立了地震观测台网,蓄水后库尾区诱发了一系列微震,形成几次水库诱发地震高潮期。本文通过库区近4年的形变观测资料的初步分析,论述了蓄水后库区地壳的稳定性及诱发地震与断层活动的关系,探讨了今后诱发较大地震的可能性。 相似文献
3.
随着众多大型水利枢纽的建设施工,在水利界逐步出现了“水库触发地震”之说。“水库诱发地震”和“水库触发地震”,虽只是一字之差,但涉及到水库地震的成因机制、水库地震预测等根本问题。统计了中外水库地震(Ms≥4.5)震例的3种地震响应时间△T1(水库蓄水至初震时间)、△T2(水库蓄水至主震时间)和△T3(初震至主震时间)的概率分布;并介绍了近几年现代大地测量学在监测水库蓄水环境变化和数字地震观测在揭示水库地震震源力学状态所取得的新进展。综合研究后认为水库蓄水局部改变了自然环境和地震孕育环境;在自然环境、地震孕育环境和地震之间可能存在着一种相互作用的动力学反馈机制,导致大约数年后具有更高震级的主震发生。因此,“水库诱发地震”是正确的,并非仅存在“触发地震”。 相似文献
4.
隔河岩水库蓄水前即开始地穿越库区的主要断裂进行监测,并设立了地震观测台网,蓄水后库尾区诱发一系列微震,形成几次水库诱发地震高潮期,本文通过库区近4年的形变观测资料的初步分析,论述了蓄水后库区地壳的稳定性及诱发地震与断层活动的关系,探讨了今后诱发较大地震的可能性。 相似文献
5.
6.
7.
湖南省黄石水库诱发地震的形成条件及成因探讨 总被引:2,自引:0,他引:2
在湖南桃源县黄石水库库区,由于张扭性活断层和深部岩溶的存在,水库蓄水后产生的附加应力场及水库区增强的岩石孔隙流体压力诱发了断层的断滑,使得库区应力集中区和岩溶发育区合二为一的地带发生构造型地震,从而在震活动的时间序列、空间规律,地震与库水位关系,震源深度、震情等方面表现出构造水库诱发地震的特点。 相似文献
8.
通过野外地震地质调查并参考前人研究成果,分析三江口水库区的地质构造背景、地震活动性及水文地质条件等资料,对该水库诱发地震的可能性进行分析。构造类比法分析表明:蓄水后发生构造型水库诱发地震的可能性较小,但有可能发生岩溶塌陷型水库诱发地震。概率预测法分析表明:库首段(新滩子—狮狸弯)发震概率较小,仅为0.02;库中段(狮狸弯—牛鼻子)岩溶不太发育,诱震可能性较小,不发震的概率为0.96;库尾段(牛鼻子—峡马口)有可能诱发微震,发震(M3.0)概率为0.10。 相似文献
9.
10.
1995年2月茄子山水库区发生了4.1级和4.2级地震。地震特点表明与水库蓄水有关。本分析了茄子山水库区的地质构造、构造应力状态、渗漏条件、地热和其它诱发地震条件,判断了茄子山水库诱发地震可能性,利用综合影响系数公式讨论了茄子山水库诱发地震的最大震级。 相似文献
11.
12.
利用动态平差原理,处理了克孜尔水库水准监测网的14期跨断层流动水准资料,对穿过库区主坝、副坝之间F2断层的形变机制进行了初步研究。结果表明F2断层的活动属继承性活动,其活动方式为小幅度蠕变。这种活动方式对库区应力集中起到了解除的作用。 相似文献
13.
分析了大朝山水库蓄水前,水库区域历史中强、强地震背景与1992年来的地震活动格局,及蓄水前9年中库坝区天然地震活动的时、空、强分布,结果表明:大朝山水库区为地震活动水平较低的区域,库坝附近30km以2、3级地震活动为主,库首方向距大坝40km左右的景谷与库尾方向距大坝50km的昌宁、凤庆一带为5级地震活动区,外围100km左右的耿马、澜沧、普洱等地区为6、7级强震活动区;库坝区的地震活动基本符合G—R关系式,b值为0.69,累积应变曲线呈稳定增长趋势,时间分布上出现活跃与平静交替的分布格局。 相似文献
14.
15.
新疆克孜尔震群活动与水库蓄水关系研究 总被引:3,自引:3,他引:3
分析了拜城县克孜尔水库附近震群的活动特征、跨断层(F2)形变测量资料及库区的地质构造和水文地质条件,认为库区附近的震群活动与水库蓄水无关,亦不属于水库诱发地震,而且不是由于F2断层活动所致。 相似文献
16.
DETERMINATION OF FAULT PLANE PARAMETERS IN THE LONGTAN RESERVOIR BY USING PRECISELY LOCATED SMALL EARTHQUAKE DATA AND REGIONAL STRESS FIELD 下载免费PDF全文
The Longtan reservoir is located in Tian'e County, Guangxi Zhuang Autonomous Region, southwestern China on the upper reaches of Hongshui River, the main stream of the Pearl River. The dam of the reservoir is 200m high, and the maximum water depth can be up to 194m as the water level reaches 400m. The reservoir storage capacity is 27.3 billion cubic meters, so it is a typical high-dam reservoir with large storage capacity. Terrain of the reservoir is high in the west and low in the east. The reservoir is located at the confluence of the Hongshui River, Buliu River, Nanpan River, Beipan River, Mengjiang River and Caodu River. The construction of Longtan hydropower station officially started in July 2001, and the reservoir impoundment was on September 30, 2006. The power station is equipped with 9 sets of 700 000kW water turbine generator units, with a total installed capacity of 6.3 million kW and an average annual generating capacity of 18.7 billion kW·h. So its storage and hydropower capacity rank third only to the world-famous Three Gorges hydropower project and the ultra-large hydropower project in Xiluodu of Jinsha River in China. Seismicity enhanced rapidly in the reservoir area after the impoundment. More the 5 000 earthquakes have been recorded so far, with the maximum magnitude of ML4.8, which occurred on September 18, 2010. The earthquakes are mainly concentrated in the deep water area where fault zones run through. Assuming the seismogenic fault can be simulated by a plane and most small earthquakes occur nearby the fault plane, the information of seismogenic fault can be obtained by the hypocenter location parameters of small earthquakes. 相似文献
17.
18.
针对我国在西南构造活跃区修建的水库蓄水与地震活动的关系,本文对蓄水已长达7年并在高水位运维多个周期的云南小湾水库,采用结合波形互相关技术的双差地震定位法对水库库区及周边地区2005年7月至2014年12月发生的M≥1.0级地震进行了精定位处理,结果显示出明显的地震成丛活动特征,库区内外的地震震源深度差别较大.对地震震源深度、地震活动与水库蓄水水位及b值分析结果表明:小湾水库蓄水后地震活动明显增多,有水库触发地震发生,触发地震主要分布在沿黑惠江(A)和澜沧江流域(B、C)的3组地震丛中,且3个区的触发地震类型均为快速响应型;在水库蓄水响应活动最明显的地震丛集区A,展现出明显的随水库蓄水水体渗透发生地震"迁移"活动的现象;但库区内也存在着与蓄水关系不大的可能属于正常构造地震的活动,而库区外的地震活动与水库蓄水没有什么相关性,很可能是属于正常的构造地震.综合断层展布、岩性分布及震源深度分析,认为水库蓄水引起的溶岩作用和渗透作用及断层活动可能是小湾水库触发地震的主控因素. 相似文献
19.
Reservoir induced earthquakes (RIE) are caused by impoundment of reservoir,with the characteristics of small magnitude and shallow focal depth,but they can also lead to not only economic loss,but also many serious secondary disasters,such as dam destruction,landslide,producing greater damages far more than the damages directly produced by earthquakes.So study on RIE is quite significant in the field of dam construction,thus more attentions should be paid to RIE.There are many factors to induce reservoir earthquakes,such as geological condition,rock mass mechanical index,state of crustal stress,pore pressure distribution,all of which are extremely difficult to measure due to the presence of many randomness;even if applying most advanced methods to measure them,the values fluctuate in great range,without a certain value in time and space.The great variety of these parameters gives rise to troubles to analyze RIE by deterministic approaches.How to handle the randomness of these factors has become vital problem in the field of RIE research.In this study,based on probability theory,and taking the main influence factors as stochastic variables,a new method to analyze probability of RIE was proposed by applying reliability theory.Firstly,the factors inducing reservoir earthquakes were analyzed,of which pore pressure in fault caused by water impounding of reservoir plays a vital role in triggering earthquakes.Then,taking these factors,including attitude,friction coefficient,cohesion of fault plane,stress state of fault plane and pore pressure in fault,as stochastic variables,performance function of triggering earthquakes was established by applying Coulomb stress on the fault plane,and reliability theory was used to analyze probability of earthquake induced by main factors.A special case analysis showed that:(1) The probability of induced earthquakes dramatically increases as pore pressure in fault increases;under the condition of equal pore pressure at triggering earthquakes area,probability of induced earthquakes obviously rises with enlarging of variation of pore pressure;(2) those faults with strike approximately parallel to horizontal maximum principal stress direction or with steep dip angle about more than 60° are prone to inducing earthquake;(3) as horizontal minimum principal stress increases,which has greater effect on induced earthquakes than horizontal maximum principal stress,probability of induced earthquakes becomes lower and fault keeps in more stable condition;(4) probability of induced earthquakes gradually decreases with the increase of friction coefficient and cohesion of fault plane;However,the effect of friction coefficient on induced earthquakes is much greater than the cohesion of fault plane. 相似文献