陕西周至地电台地电阻率年变特征分析   总被引：1，自引：0，他引：1       下载免费PDF全文

石富强  张国强  方炜  邵辉成  张国苓 《地震学报》2014,36(6):1113-1123

本文基于测深反演结果, 通过数值模拟定性分析了地下水位和降雨对周至地电台地电阻率观测的影响; 同时利用褶积算法定量分析了降雨对该台NS向和NE向地电阻率观测的短期影响和长趋势影响.结果表明, 周至地电台地电阻率年变主要由地表薄层介质电阻率季节变化引起, 受地下水位变化影响不明显. 降雨对NS向和NE向地电阻率观测值的影响在短期内与观测结果一致, 表现为增加; 但长期趋势则与观测结果呈负相关关系.根据数值模拟分析认为, 这种变化与降雨及其渗透深度有关.分析结果与实际观测结果一致, 为正确认识周至地电台地电阻率观测与异常判定提供合理的理论依据.   相似文献   

新疆尼勒克、巩留交界6.0级地震灾害损失评估与房屋震害特征     

谭明  唐丽华  吴国栋  常想德  张勇  宋立军  李洋  李亦纲  王伟  石广岭  李志海 《中国地震研究》2014,28(2):261-273

新疆尼勒克、巩留交界6.0级地震震中烈度为Ⅶ度,地震没有造成人员伤亡,但个别民宅倒塌,大量村镇居民房屋遭受中等以上破坏,一些教育、卫生等公房遭破坏;交通和水利设施有一定程度破坏,经及时抢修,未对灾区生产生活产生明显影响。通过实地抽样调查和统计计算,评估出本次地震造成的直接经济损失为67 846万元,需恢复重建的经费120 349万元。  相似文献   

云南彝良“9?7地震”前异常特点     

孙宗强  师娅芳  高华宴  芮文军  冯亮亮  徐芳芳  曹晓丽  王斌  王咏梅 《中国地震研究》2014,28(2):250-260

对2012年9月7日云南省昭通市彝良县洛泽河一带5.7、5.6级地震前地震活动和前兆异常分析,其地震活动特征、流体和形变动态变化及预测指标,发现：地震前4级地震活动水平增强、出现小震活动空区;前兆异常开始于震前1年左右;短期异常有由外围向震中迁移的现象;临震异常出现的时间较为集中,震前一周内。对该地区5.0级以上强震的预报和研究具有一定的指示意义。  相似文献   

Professor Zhao-Yin Wang,Ph.D.,M.ASCE Editor-in-Chief of the International Journal of Sediment Research     

John Z.Shi  Hong-Wei Fang 《国际泥沙研究》2014,(1)

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测震台网强震影响范围快速判定     

曲均浩  董翔  肖兰喜  石玉燕  张志慧  崔鑫  李铂 《地震地磁观测与研究》2014,35(5):312-318

以测震台网Jopens系统流服务为依托,根据NetSeis/IP协议通讯标准实时接收数据包,解析MiniSEED格式波形数据,监控台站波形中断情况,实现基于REST架构的台站状态显示,结合震中附近地质构造信息,快速判定地震破坏扩展方向,圈定极震区范围,为地震应急决策服务.  相似文献   

Defining the range of ecological shelter zones in the shore zone of Three Gorges Reservoir,China     

Jie Feng  Youbing Hu  Zhijia Li  Tao Yang  Pengfei Shi 《Stochastic Environmental Research and Risk Assessment (SERRA)》2014,28(8):1973-1984

To maintaining a health ecological environment in Three Gorges Reservoir (TGR) area, ecological shelter zones (ESZ) need to be built in the TGR shore zone urgently. Based on the implication and function of ESZ, this study first analyzed the relationships amongst three subsystems of the TGR area, including the upstream production-living land, the downstream reservoir water body, and the ESZ. Then a simple and practical hydrological environment model for controlling the eutrophication of the TGR water body was constructed to determine ESZ range of TGR. Additionally, based on the pollutant degradation efficiency of ESZ and the assimilative capacity of reservoir water body, a raster reverse tracking method was proposed to determine the range of ESZ. Thirdly, take Yangdu town in Zhongxian county as a typical region, the ESZ range under three scenarios of different rainfall intensity, degradation efficiency and inflow water quality that corresponding to the three decisive factors of defining ESZ range were discussed. Finally, the statistical laws of the ESZ’s width at each boundary points were discussed to facilitate the ESZ construction projects, and selected standardized rate at 70, 90, and 99 % were labelled as “General”, “Good” and “Excellent” level to represent the performance of the width of the ESZ range. In conclusion, it suggest “Good” level width as basic width of ESZ, and additionally a special protection zone should be put on upstream environment for the extreme large width at the boundary points.  相似文献   

Influence of confining pressure and impact loading on mechanical properties of amphibolite and sericite-quartz schist     

Shi Liu  Jinyu Xu  Xiaocong Lv 《地震工程与工程振动(英文版)》2014,13(2):215-222

In order to investigate the dynamic mechanical properties of amphibolite and sericite-quartz schist under confi ning pressure, two rocks are subjected to impact loadings with different strain rates and confi ning pressures by using split Hopkinson pressure bar equipment with a confi ning pressure device. Based on the experimental results, the stress-strain curves are analyzed and the effects of confi ning pressure and strain rates on the dynamic compressive strength, peak strain and failure mode are summarized. The results show that:(1) The characteristics of two rocks in the ascent stage of the stressstrain curve are basically the same, but in the descent stage, the rocks gradually show plastic deformation characteristics as the confi ning pressure increases.(2) The dynamic compressive strength and peak strain of two rocks increase as the strain rate increases and the confi ning pressure effects are obvious.(3) Due to the effect of confi ning pressure, the normal stress on the damage surface of the rock increases correspondingly, the bearing capacity of the crack friction exceeds the material cohesion and the slippage of the fractured rock is controlled, which all lead to the compression and shear failure mode of rock. The theoretical analysis and experimental methods to study the dynamic failure mode and other related characteristics of rock are useful in developing standards for engineering practice.  相似文献   

On numerical earthquake prediction          下载免费PDF全文

Yaolin Shi  Bei Zhang  Siqi Zhang  Huai Zhang 《地震科学（英文版）》2014,27(3):319-335

Can earthquakes be predicted? How should people overcome the difficulties encountered in the study of earthquake prediction? This issue can take inspiration from the experiences of weather forecast. Although weather forecasting took a period of about half a century to advance from empirical to numerical forecast, it has achieved significant success. A consensus has been reached among the Chinese seismological community that earthquake prediction must also develop from empirical forecasting to physical prediction. However, it is seldom mentioned that physical prediction is characterized by quantitatively numerical predictions based on physical laws. This article discusses five key components for numerical earthquake prediction and their current status. We conclude that numerical earthquake prediction should now be put on the planning agenda and its roadmap designed, seismic stations should be deployed and observations made according to the needs of numerical prediction, and theoretical research should be carried out.  相似文献   

Failure time variation derived from R–S relation: the role of the static stress perturbation          下载免费PDF全文

Qiu Zhong  Wenhao Shen  Baoping Shi 《地震科学（英文版）》2014,27(1):37-46

In general, earthquake cycle related to earthquake faulting could include four major processes which could be described by (1) fault locking, (2) self-acceleration or nucleation (possible foreshocks), (3) coseismic slip, and (4) post-stress relaxation and afterslip. A sudden static stress change/perturbation in the surrounding crust can advance/delay the fault instability or failure time and modify earthquake rates. Based on a simple one-dimensional spring-slider block model with the combination of rate-and-state-dependent friction relation, in this study, we have approximately derived the simple analytical solutions of clock advance/delay of fault failures caused by a sudden static Coulomb stress change applied in the different temporal evolution periods during an earthquake faulting. The results have been used in the physics-based explanation of delayed characteristic earthquake in Parkfield region, California, in which the next characteristic earthquake of M 6.0 after 1966 occurred in 2004 instead of around 1988 according to its characteristic return period of 22 years. At the same time, the analytical solutions also indicate that the time advance/delay in Coulomb stress change derived by the dislocation model has a certain limitation and fundamental flaw. Furthermore, we discussed the essential difference between rate- and state-variable constitutive (R–S) model and Coulomb stress model used commonly in current earthquake triggering study, and demonstrated that, in fact, the Coulomb stress model could be involved in the R–S model. The results, we have obtained in this study, could be used in the development of time-dependent fault interaction model and the probability calculation related to the time-dependent and renewal earthquake prediction model.  相似文献   

The April 24, 2013 Changning M s4.8 earthquake: a felt earthquake that occurred in Paleozoic sediment          下载免费PDF全文

Xiangfang Zeng  Libo Han  Yaolin Shi 《地震科学（英文版）》2014,27(1):107-115

The dense broadband seismic network provides more high-quality waveform that is helpful to improve constraint focal depth of shallow earthquake. Many shallow earthquakes occurring in sediment were regarded as induced events. In Sichuan basin, gas industry and salt mining are dependent on fluid injection technique that triggers microseismicity. We adopted waveform inversion method with regional records to obtain focal mechanism of an M _s4.8 earthquake at Changning. The result suggested that the Changning earthquake occurred at a ESE thrust fault, and its focal depth was about 3 km. The depth phases including teleseismic pP phase and regional sPL phase shows that the focal depth is about 2 km. The strong, short-period surface wave suggests that this event is a very shallow earthquake. The amplitude ratio between Rayleigh wave and direct S wave was also used to estimate the source depth of the mainshock. The focal depth (2–4 km) is far less than the depth of the sedimentary layer thickness (6–8 km) in epicentral region. It is close to the depth of fluid injection of salt mining, which may imply that this event was triggered by the industrial activity.  相似文献