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本文开展汶川地震断裂带科学钻探现场流体研究,探讨了泥浆添加剂产生的化学反应以及钻孔中岩性变化引起的流体异常特征,并在排除这些影响因素的情况下,讨论地震期间流体的异常。研究表明在WFSD-4S钻进期间发生的两次较大地震前均伴有Rn、Ar、N2和O2等气体异常现象,其中氡的日均值均超出背景值的2.5倍。根据岩心观察得到WFSD-4S钻井地区主断层约在1084 m,而在断层之上931 m处开始出现了大量气体的高值异常,该异常可能是由于地震孕育过程中地下气体的运移通道被打开造成气体向上迁移,使断层气体的响应特征提前发生。 相似文献
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本文首先对龙羊峡水库地震活动期间的水压位移场、水压应力场和固体潮应力张量进行了计算;然后分析了此期间的微震活动与各种因素的关系,从而提出本区水库地震的诱发过程是“库水渗透——提高岩体局部段的现今应力水平——库水荷载效应和固体潮该为张量的联合激发作用——裂纹串通(或扩展)——发震”的观点;最后在此基础上对龙羊峡未来水库地震危险性进行了预测。 相似文献
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地震地质工作的缘起与回顾 总被引：1，自引：0，他引：1
刘光勋 《地壳构造与地壳应力》2006,(2):15-18
地壳应力研究所(前地震地质大队)于1966年4月正式成立,这标志自1962年广东新丰江6.1级地震发生后至1966年河北邢台发生6.8级地震期间,在李四光亲自指导和筹划下,我国首批地震地质专业队伍组建完成。这一支队伍的出现不是偶然的,故然与邢台地震的发生及其造成严重的损失直接相关 相似文献
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“八五”期间是江苏油田历年来非地震勘探工作量最大、开展项目最多的时期,这为油田拓宽勘探领域,尤其是深层勘探发挥了作用。1 非地震勘探工作“八五”期间江苏油田的非地震勘探(表1)共开 相似文献
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杭州钱塘江防洪堤抗震分析 总被引：2，自引：0，他引：2
通过动力试验研究了杭州钱塘江防洪堤基的动力特性,并用原位和室内分析法判别了堤基液化的可能性,在有限元分析时,改进了工程上常用的排水有效应力动反应分析方法,在地震期间采用Biot动力固结方程进行动力分析,可以同时考虑地震期间孔压的上升及固结消散对防洪堤的抗震液化和稳定性进行分析。采用非线性成层地基反演技术,反演分析基岩地震加速度曲线,对堤坝地震反应进行分析。地震响应的各种结果对于了解今后防洪堤在地震期间的运行状态具有一定指导意义。 相似文献
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《地壳构造与地壳应力文集》2014,(0)
很多时候地震谣言的危害不亚于一次中等强度的地震,其对社会的稳定和经济的发展有很大影响。本人全面分析了地震谣言的出现及盛行的原因、类型和识别方法等谣言的特征,在此基础上提出了预防和平息地震谣言的对策,这对预防和迅速平息地震谣言具有重要的现实意义。 相似文献
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汶川地震诱发了大量的次生地质灾害,陇南红土坡滑坡在地震期间局部发生崩塌并出现大量拉张裂缝,该滑坡一旦整体复活滑动,将堵塞北峪河形成堰塞湖,对北峪河下游陇南武都城区8万人以及红土坡上游村庄928人的生命财产安全造成极大威胁。因此准确判断该滑坡稳定性,并采取相应的防治措施尤为重要。本文基于滑坡区地质环境,通过区域地质调查、坡微地貌和变形破坏特征测量等手段,对红土坡滑坡特征和成因进行了系统研究。研究成果表明,该滑坡具有显著的分级分块滑动特性,地震、降雨、河流冲刷及不良的岩土体工程地质性质是形成该滑坡的主要因素。在分析滑坡成因的基础上,采用传递系数法等手段,定性与定量相结合,评价该滑坡在天然、暴雨和地震工况下的稳定性,并提出了预应力锚索框架+拦挡坝+排水+护岸墙等综和防治对策。 相似文献
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渝利铁路青石岩段为深切河谷型边坡,该边坡表部岩体在风化缷荷作用下结构复杂且稳定性差。此外,浅表层岩体在降雨、地震及工程开挖等影响下,局部已经出现了不同模式不同规模的变形失稳现象,严重影响工程建设和运营期间的安全。因此,本文根据边坡岩体结构特征及风化缷荷特征等工程地质条件,结合不同失稳模式的危岩体,提出了相应的稳定性评价理论和方法。最后,针对不同规模和不同稳定状态下的危岩体提出了有效的防治措施。 相似文献
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The present status of reservoir induced seismicity investigations with special emphasis on Koyna earthquakes 总被引：2，自引：0，他引：2
Harsh K. Gupta 《Tectonophysics》1985,118(3-4)
The status of Reservoir Induced Seismicity (RIS) has been reviewed periodically (Rothé, 1968, 1973; Gupta and Rastogi, 1976; Simpson, 1976; Packer et al., 1979). In the present paper, the significant work carried out during the last three years on RIS is reviewed.An earthquake of magnitude
occurred on November 14, 1981 in the vicinity of Aswan Lake, Egypt, 17 years after the filling started in 1964. This event occurred 4 days after the seasonal maximum in the reservoir water level and was followed by a long sequence of aftershocks. Another event of magnitude
occurred in the vicinity of Aswan Lake on August 20, 1982. Results of preliminary investigations indicate that this seismic activity is reservoir induced. Recent analyses of induced seismic events at Nurek Reservoir U.S.S.R., show that the second stage of filling during August to December 1976, increasing the maximum depth from 120 m to 200 m, was accompanied by an intense burst of shallow seismic activity. An outward migration from the centre of the reservoir, possibly associated with diffusion of pore pressure, is revealed by the temporal distribution of earthquake foci. A variety of investigations including the in situ measurement of tectonic stress, pore pressure, permeability, distribution of faults, etc., in addition to monitoring seismicity, have been undertaken in the vicinity of the Monticello Reservoir, South Carolina. The largest reservoir induced earthquake is predicted not to exceed magnitude 5.The Koyna Reservoir, India, continues to be the most outstanding example of RIS. Three earthquakes of magnitude
5 occurred in September 1980. Earthquakes of magnitude 4 occur frequently in the vicinity of Koyna, the latest being on February 5, 1983. Events that occurred during the period 1967–1973 have been relocated using better procedures and are found to be much shallower and the epicentres less diffused. Location of 12 earthquakes of Ms 4.0, their foreshocks and aftershocks, that occurred during 1973–1976, composite focal mechanism solutions and related studies are consistent with the delineation of a N-S trending fault through the reservoir area. In a couple of interesting studies it has been demonstrated that earthquakes of magnitude 5.0 in the Koyna region are usually preceded by several magnitude 4 earthquakes in the preceding fortnight. Also, a rate of loading of Koyna reservoir of at least 40 ft/week appears to be a necessary, although not sufficient, condition for the occurrence of magnitude 5 earthquakes. Smooth filling/emptying appears to be the key to reduce the hazard of RIS.A map and a table of the reported cases of reservoir induced changes in seismicity through 1982 have been compiled. 相似文献
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小浪底水库异重流的形成与运行规律是关系黄河调水调沙方案拟定的重要指标。基于现场调研、理论探讨与预测分析结合等手段,明晰了2018年"腾库迎洪"期小浪底水库来水来沙过程,根据水库调度与库区淤积形态等边界条件,观测了异重流的形成与运行,采用基于流速分布的水库异重流潜入点预测公式进行了计算分析。结果表明:2018年7月库区产生的剧烈冲刷,在潜入点处发生大量淤积,水深大幅减小,引起潜入点下移;潜入点位置随入库水沙增大、坝前水位降低及库区淤积的推进向坝前移动,计算与实测结果反映了该变化过程。 相似文献
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小浪底水库异重流的形成与运行规律是关系黄河调水调沙方案拟定的重要指标。基于现场调研、理论探讨与预测分析结合等手段,明晰了2018年“腾库迎洪”期小浪底水库来水来沙过程,根据水库调度与库区淤积形态等边界条件,观测了异重流的形成与运行,采用基于流速分布的水库异重流潜入点预测公式进行了计算分析。结果表明:2018年7月库区产生的剧烈冲刷,在潜入点处发生大量淤积,水深大幅减小,引起潜入点下移;潜入点位置随入库水沙增大、坝前水位降低及库区淤积的推进向坝前移动,计算与实测结果反映了该变化过程。 相似文献
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三峡库区蓄水以来,长江周边出现了大量的水库地震,主要集中于巴东—泄滩—仙女山区域,目前已达上万次,最大震级为5.1级。通过野外地质调查及对已有水库地震数据进行研究,采用构造地质分析方法,对三峡库区仙女山和九畹溪断裂带水库地震空间上的迁移规律、时间上的周期规律以及微地震群的成因机理进行分析。结果表明：从时间上看,水库地震具有周期性,表现为长周期（与库水位相关）和短周期（与库水位快速波动相关）;从空间上看,水库地震具有迁移规律,受九畹溪断裂控制的触发型水库地震存在着逐渐向南迁移的特征,受仙女山断裂控制的触发型水库地震局限分布于仙女山断裂北延端点处,分布于仙女山断裂西侧（周坪乡附近）带状分布的水库诱发地震逐渐呈点状向南迁移。 相似文献
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水库淤积形态是影响库容分布、水库排沙的一项重要因素。小浪底水库近坝段淤积泥沙粒径极细,具有流动性,针对其细颗粒泥沙淤积特点,揭示了水库细颗粒淤积物的流变特性与流型特征;通过引入水、淤积物、床面之间的界面受力分析,构建了细颗粒淤积物失稳流动描述模式,并与水沙输移模型相耦合,建立了考虑细颗粒淤积物流动特性的水库淤积形态模拟方法,在此基础上对小浪底水库淤积形态进行了验证分析。研究结果表明:低密度细颗粒淤积物为宾汉型流体,淤积平衡坡降较小,当其密度大于1.25 g/cm 3后,流动性快速减弱;考虑细颗粒淤积物流动特征的水库淤积形态模拟结果与实测结果吻合较好。研究成果可为水库淤积形态形成机理及其对水沙调控的响应研究提供技术支撑。 相似文献
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水库淤积形态是影响库容分布、水库排沙的一项重要因素。小浪底水库近坝段淤积泥沙粒径极细,具有流动性,针对其细颗粒泥沙淤积特点,揭示了水库细颗粒淤积物的流变特性与流型特征;通过引入水、淤积物、床面之间的界面受力分析,构建了细颗粒淤积物失稳流动描述模式,并与水沙输移模型相耦合,建立了考虑细颗粒淤积物流动特性的水库淤积形态模拟方法,在此基础上对小浪底水库淤积形态进行了验证分析。研究结果表明:低密度细颗粒淤积物为宾汉型流体,淤积平衡坡降较小,当其密度大于1.25 g/cm3后,流动性快速减弱;考虑细颗粒淤积物流动特征的水库淤积形态模拟结果与实测结果吻合较好。研究成果可为水库淤积形态形成机理及其对水沙调控的响应研究提供技术支撑。 相似文献
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小浪底水库遥测地震台网建设技术探讨 总被引：1，自引：1，他引：1
本文阐述了小浪底水库遥测地震台网建设过程中的有关技术问题, 对总体设计、基本建设、设备选购、配置及安装调试等各个阶段的技术难点、重点, 进行了全面剖析, 提出了自已的见解, 对水库遥测地震台网的规划和建设具有一定的指导意义。 相似文献
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Wang Miao-yueh Yang Mao-yuan Hu Yu-liang Li Tzu-chiang Chen Yun-tai Chin Yen Feng Jui 《Engineering Geology》1976,10(2-4):331-351
After the filling up of the Hsinfengkiang Reservoir Kwangtung Province, seismicity was greatly increased. The majority of earthquakes occurred in the deep water gorge close to the dam, concentrated within a northwest belt. They are usually of shallow focal depths. A strong earthquake with magnitude 6.1 took place on March 19, 1962, about two and a half years since the impounding of the reservoir.
According to the results of analysis of data from geodetic leveling and the spectra of seismic waves, the fault parameters of the main shock were determined. The fault plane solutions of 150 small earthquakes, occurring within a period of 18 months before and after the main shock were determined from the amplitudes of the first motion of P wave. The directions of the earthquake generating stress of about 2000 small earthquakes were obtained by smoothing the first motion patterns. Displacement field and stress field in the rock bodies underneath the reservoir caused by the loading of the reservoir water were calculated. Variations of the velocity ratio of the P and S waves prior to the main shock and several strong aftershocks were analysed.
In consideration of the seismicity as well as the geological background, we endeavour to discuss the cause of reservoir impounding earthquakes at Hsinfengkiang. We have the opinion that the penetration of water along fissures becomes the most important cause of the main shock of March 19, 1962 at Hsinfengkiang. 相似文献
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Harsh K. Gupta 《Journal of the Geological Society of India》2017,90(6):645-652
The Koyna earthquake of M 6.3 on December 10, 1967 is the largest artificial water reservoir triggered earthquake globally. It claimed ～ 200 human lives and devastated the Koyna township. Before the impoundment of the Shivaji Sagar Lake created by the Koyna Dam, there were no earthquakes reported from the region. Initially a few stations were operated in the region by the CentralWater and Power Research Station (CWPRS). The seismic station network grew with time and currently the National Geophysical Research Institute (NGRI), Hyderabad is operating 23 broadband seismographs and 6 bore hole seismic stations. Another reservoir, Warna, was created in 1985, which provided a further impetus to Reservoir Triggered Seismicity (RTS). Every year following the monsoon, water levels rise in the two reservoirs and there is an immediate increase in triggered earthquakes in the vicinity of Koyna-Warna reservoirs in the months of August–September. Peak RTS is observed in September and later during December.Another spurt in triggered earthquakes is observed during the draining of the reservoirs in the months of April- May. A comparative study of RTS earthquake sequences and the ones occurring in nearby regions made it possible to identify four common characteristics of RTS sequences that discriminate them from normal earthquake sequences. As the RTS events continue to occur at Koyna in a large number in a limited area of 20 km x 30 km, at shallow depths (mostly 2 to 9 km), the region being accessible for all possible observations and there being no other source of earthquakes within 100 km of Koyna Dam, it was suggested to be an ideal site for near field observations of earthquakes. This suggestion was discussed by the global community at an ICDP sponsored workshop held at Hyderabad and Koyna in 2011. There was an unanimous agreement about the suitability of the site for deep scientific drilling; however, a few additional observations/experiments were suggested. These were carried out in the following three years and another ICDP workshop was held in 2014, which totally supported setting up a borehole laboratory for near field investigations at Koyna. Location of a Pilot Bore-hole was decided on the basis of seismic activity and other logistics. The 3 km deep Pilot Borehole was spudded on December 20, 2016 and completed on June 11, 2017. 相似文献
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大型水利水电工程水库诱发地震历来受业主、工程技术人员的重视。三峡工程蓄水10多年来,在蓄水过程中,三峡库区较蓄水前地震明显增多。本文选择了三峡库区既有活动断裂,又有可溶岩和煤层分布的近坝库段作为研究对象,通过对库区地震活动与水位的关系和诱发地震空间展布特征分析,认为:三峡水库诱发地震,发生在有可溶岩和含煤地层部位的塌陷型地震占总数的90%,而非可溶岩和不含煤地层中只占总数的10%;近坝库段地震主要发生在仙女山断层北端,且有地震呈丛集活动的特征;九湾溪断层上盘远离长江部位地震零星分布,距长江较近地段地震相对增多,下盘地震极少。地震与水位的对应关系十分密切,三峡水位上升,长江两岸发生的小地震较多,当水位蓄至175m时,地震主要发生在仙女山断裂的北端和九湾溪断裂的上盘及北端。 相似文献