GPS揭示的现今地壳运动与地震前兆特征   总被引：10，自引：8，他引：2  

吴云  孙建中  乔学军  王辉  张燕  施顺英 《大地测量与地球动力学》2003,23(3):14-20

利用“中国地壳运动观测网络”产出的GPS观测资料,采用球坐标系下非连续变形算法对资源进行计算,以此为基础,对我国大陆地块及其边界带运动与形变进行了分析。对GPS基准站的连续观测序列采用小波变换进行分解变换,分析了部分震例,探讨了从GPS连续观测序列提取地震前兆的方法。初步取得两点认识：（1）7级以上的大地震主要发生在走滑运动量大的活动边界,且与高应变率地块有关,这可以作为地震中长期预测判据;（2）GPS基准站连续观测序列中的低频段,地震前6个月或稍长时段有一定的前兆异常出现,这可以作为地震中短期预测判据。  相似文献   

长江三峡库区(奉节-巴东段)移民工程遥感动态监测   总被引：2，自引：0，他引：2  

刘波坤孟淑英  李述靖王学佑 《地球信息科学学报》2002,4(4):63-68,119

在长江三峡库区移民工程中 ,我们采用 ETM+、SPOT、IKONOS等多源、多时相、多分辨率航天、航空遥感数据组合 ,监测移民工程的动态变化 ,通过对库区奉节 -巴东段移民搬迁建与安置、新开发用地分布、土地利用与土地结构变化、地质灾害及衍生地质灾害与防治、库区环境及生态平衡与改善经济结构以及移民工程遥感动态监测等 ,取得突破性进展 ,获取了一批重要成果。为三峡移民工程进一步全面、安全地实施、改进规划管理工作及库区经济可持续发展 ,提供了科学依据和决策性建议。  相似文献   

Seismic Hazard and Risk Assessment for Tulbagh,South Africa: Part I – Assessment of Seismic Hazard     

Kijko  A.  Retief  S. J. P.  Graham  G. 《Natural Hazards》2002,26(2):175-201

In this part of our study the probabilistic seismic hazard analysis (PSHA) for Tulbagh was performed. The applied procedure is parametric and consists essentially of two steps. The first step is applicable to the area in the vicinity of Tulbagh and requires an estimation of the area-specific parameters, which, in this case, is the mean seismic activity rate, , the Gutenberg-Richter parameter, b, and the maximum regional magnitude, m_max. The second step is applicable to the Tulbagh site, and consists of parameters of distribution of amplitude of the selected ground motion parameter. The current application of the procedure provides an assessment of the PSHA in terms of peak ground acceleration (PGA) and spectral acceleration (SA). The procedure permits the combination of both historical and instrumental data. The historical part of the catalogue only contains the strongest events, whereas the complete part can be divided into several subcatalogues, each assumed complete above a specified threshold of magnitude. In the analysis, the uncertainty in the determination of the earthquake was taken into account by incorporation of the concept of `apparent magnitude'. The PSHA technique has been developed specifically for the estimation of seismic hazard at individual sites without the subjective judgement involved in the definition of seismic source zones, when the specific active faults have not been mapped or identified, and where the causes of seismicity are not well understood. The results of the hazard assessment are expressed as probabilities that specified values of PGA will be exceeded during the chosen time intervals, and similarly for the spectral accelerations. A worst case scenario sketches the possibility of a maximum PGA of 0.30g. The results of the hazard assessment can be used as input to a seismic risk assessment.  相似文献   

A Study of Seismicity and Earthquake Hazard at the Proposed Kalabsha Dam Site,Aswan, Egypt     

Fat-Helbary  Raafat E.  Tealb  Aly A. 《Natural Hazards》2002,25(2):117-133

High and Aswan Dams Authority (HADA) proposed a plan aiming at constructing a rockfill dam in the Kalabsha area, about 60 km south of Aswan High Dam. The aim of this dam is to restrain the overflow of water to the Kalabsha Valley for keeping one billion cubic meters from being lost due to seepage and evaporation. The safety of dams during earthquakes is extremely important because failure of such a structure may have disastrous consequences on life and property. Therefore, different factors were considered as part of a site assessment. Five seismic source zones, close enough to the site to give rise to potentially damaging earthquake ground motions, were identified. Seven active faults that have the potential for producing significant earthquakes and that pass through or near the dam site were also identified. The earthquake loading represented by ground motions at the site was evaluated. Probabilistic seismic hazard procedures were used for assessing the earthquake loading at six individual sites using Area-and Line-Source Models (ASM & LSM). The ASM is based on current observed seismicity, whereas the LSM is based on geological slip rates. The output represents the expected acceleration amplitude with 90 percent probability of not being exceeded in exposure times of 20, 50, and 100 years. The results from the two models appear to be different, the expected ground motions from ASM were twice as high as expected from LSM. This difference is due to the load of the Aswan reservoir (Nasser Lake) triggering earthquakes on those parts of the faults that lie under the lake at Kalabsha area. The hazard at the selected sites is given by the hazard curve that is represented by the relationship between the peak ground acceleration and its annual exceedance probability. By comparing the curves for the six individual sites for the same source model, it can be concluded that the potential ground acceleration level for all the sites is almost the same. Considering the mean results from the two models, the annual exceedance probability of the expected ground acceleration from ASM is approximately ten times higher than the annual exceedance probability from LSM.Since ASM is based on current seismicity, it is more appropriate forrepresenting the actual hazard for the dam site.  相似文献   

基于抗震性态的设防标准研究   总被引：11，自引：0，他引：11       下载免费PDF全文

谢礼立  马玉宏 《地震学报》2002,24(2):200-209

以基于性态的抗震设计为出发点,并以我国为例,针对目前国内外抗震设防标准的若干问题和不足,提出了基于性态抗震设计的三环节抗震设防方法．将现有的设防内容改为确定结构的抗震设计类别、确定设计烈度或设计地震动参数、确定建筑的重要性等级３个方面,并分别在每一方面进行具体深入的研究,从而形成了一套完整的基于性态的抗震设防标准确定的原则、方法和框架,可以直接用来编制规范供抗震设计使用．   相似文献   

辽宁省数字地震前兆观测资料评价及其应用     

王海燕  王玉莹 《东北地震研究》2002,18(3):74-80

本文利用多种数学方法对“九五”期间辽宁省地震前兆台网数字化改造后的观测资料进行了分析处理,并对各测项数据进行了质量评价。分析认为,数字观测资料在精度,数据稳定性和可靠性等各方面均达到预报指标要求。  相似文献   

测汞用光纤传感器的初步研制   总被引：1，自引：0，他引：1  

潘树新  刘耀炜 《地震》2002,22(4):149-154

利用原子吸收原理初步研制了一种测示用光纤传感器,解决了光纤探头部分的技术难题。与传统的测汞仪器相比,该仪器的最大优点是可动的。中介绍了仪器的工作原理及主要技术性能。实验表明,可以利用光纤传感技术来实现汞测量。  相似文献   

"三联式"资源定量预测与评价--数字找矿理论与实践探讨   总被引：42，自引：4，他引：38  

赵鹏大 《地球科学》2002,27(5):482-489

随着信息技术的发展,矿产勘查已步入数字化,定量化研究的新阶段。“三联式”成矿预测及资源评价途径正是“数字找矿”的创新探索。“三联式”成矿预测以地质异常分析为基础,以成矿多样性分析与矿床谱系研究为指导,将地质异常,成矿多样性及矿床谱系三方面定量化研究紧密结合形成矿产预测及定量评价的有机切入点,是实现全面数字找矿的必由之路,也是矿产勘查评价领域应用信息技术的基础和前提。  相似文献   

1997年伽师强震群活动的近场定点形变异常特征   总被引：3，自引：0，他引：3  

温和平 《华南地震》2000,20(2):40-46

对１９９７年伽师强震群前后的近场宁点形变资料和卡尔曼滤波结果的前兆异常进行了分析,结果表明,震前短临异常较为明显。通过密切跟踪,在后续强震的预报中发挥了重要作用。文中还对异常与孕震构造和应力场的关系进行了讨论。  相似文献   

地电学地震预报方法软件系统(GSEP)   总被引：1，自引：0，他引：1       下载免费PDF全文

郝臻  杜学彬  王静波 《地震工程学报》2000,22(2):154-159

简要介绍了地电学地震预报方法软件系统（ＧＳＥＰ）的结构、主要功能、技术特点、应用范围、软件运行环境、研制开发平台、性能技术指标以及可进一步开发的内容和推广应用前景。  相似文献