共查询到20条相似文献，搜索用时 125 毫秒
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对延庆地震台水温观测资料进行分析,发现水温变化与水位变化密切相关;针对观测中出现的典型干扰提出解决办法：在泄流管最高端加装排气管解决憋气问题;在水温地线接入地网前加装电感,解决气氡观测造成的干扰问题等,并提出其他日常观测需注意的事项. 相似文献
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延庆地震台五里营井动水位2010年1月13日15时48分突然大幅下降,7min下降0．47m,针对此异常变化,台站人员通过检查仪器运行、观测环境等多方面查找原因,逐项排除干扰因素,最后通过科学、系统的分析,判定此异常是由于地下泄流管破裂,造成水位迅速下降,非地震前兆异常,避免了误报地震,为水位异常判断积累了一定经验。 相似文献
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展示了数十年来国内外科研机构运用地下流体测项中氟氯离子及水电导的异常特征探索防震减灾的突出成果。在分析了异常特征可能的产生机理后指出:流体测项中氟氯离子及水电导很可能是我们探寻多年的地化敏感元素,该元素抗干扰能力强,映震效果好,测试方便快捷,既经济又可靠。建议各地区结合本地化学、地质构造特征做到扬长避短,在不适合进行水位和水气观测的井泉多开展对氟氯及其他离子元素和水电导的多项目的综合监测研究,做到一井多用,监测有重点,分析有全面。 相似文献
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怀 4井为国家重点观测井,在多次地震前都有明显的异常出现,对监视北京西北地区的地震起着重要的作用。文中分析了 5次中强地震前怀 4井地下流体测项的异常情况。统计了自 1998年以来周围 300km范围内 4级以上地震前怀 4井流体测项的映震情况。认为怀 4井对其周围 260km范围内≥4 0级的地震反应比较灵敏。并归纳出怀 4井流体测项前兆异常的如下特征: 1)水汞前兆异常形态为突跳型,异常结束后发震; 2)断层气二氧化碳前兆异常形态为多点高值起伏型,异常转折下降中发震; 3)水氡前兆异常形态为阶变型,异常中发震; 4)氢气前兆异常形态为突跳型,异常结束后发震。通过本研究,有助于今后对怀 4井流体异常的识别,根据怀 4井各测项对地震孕育各阶段反映的差异,更容易判定未来地震的发震时刻 相似文献
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依据 《中国震例》 资料,统计分析了云南地区1966—2006年MS≥5.0地震的地下流体测项异常,结果表明:超过70%的水位和水温震前异常表现为上升,水氡和水位异常出现时间最早;震级越大相应的流体异常范围就越大;大多数震前流体异常会持续到地震发生,说明流体异常与震前地壳活动有关,并据此得出云南地区地震发生时间及异常检测井至震中距离的经验性边界方程。分类汇总云南地区地下流体测项的异常形态,识别出该地区地下流体异常的5种主要异常形态,即趋势转折类、周期类、突变类、阈值类和综合类,并举例阐明了各种异常形态的特征及其可能的成因。本文研究结果对于认识云南地区流体异常特征以及提升流体异常应用水平具有一定的参考意义。 相似文献
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昆仑山口西8.1级地震在四川地区的前兆异常效应 总被引：2，自引：0，他引：2
对昆仑口西8.1级地震发生前后四川地区地震前兆监测台网的测值曲线进行了系统的清理，发现存在有明显的孕震效应和震时效应，异常效应的幅度很大，容易鉴别，这对人类认识特大地震的影响场很有意义。 相似文献
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G. Bauer 《洁净——土壤、空气、水》1989,17(3):349-351
The sampling device consists of a weighted wide-necked bottle with a siphon pipe inserted in its top through which water enters the bottle while air escapes out of the bottle through a pipe with a valve that is inserted in the top, too. Due to the variable setting of the valve the period of time for the filling of the bottle can be controlled between few minutes and up to 24 h. 相似文献
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The dynamic behaviour of above-ground oil pipelines which are allowed to slide back and forth on intermediate supports during strong motion earthquakes is studied. This sliding is resisted by friction between the pipe and the top of the support. The main objective of the study is to determine the effect of this non-linear friction on both the static and dynamic stresses in the pipe. The study also considers the influence of other critical parameters such as: pipeline configuration, seismic wave velocity, initial temperature differential and internal pressure, and ground motion characteristics. Results show that the critical bending moments in the pipe occur during the static loading and that with seismic excitation, these moments tend to shake down as the pipe moves to a more stress free configuration. It is shown that the use of sliding friction can be an effective means of dissipating seismic energy and thereby damping the dynamic response of the pipeline even for low values of the coefficient of friction. 相似文献
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Richard L. Pfeffer William W. Fowlis Jay Fein James Buckley 《Pure and Applied Geophysics》1970,81(1):263-271
Summary The transition between axisymmetric and wave convection in a rotating, cylindrical annulus of fluid subjected to a horizontal temperature gradient is usually determined in laboratory experiments by visually observing the motion of tracer particles at the top surface of the fluid. More recent transition determinations by means of small transducers suspended within the body of the fluid give evidence of quantitative disagreement with the visual method. The dgree of disagreement and experimental details are discussed in this note.Contribution No. 20 of the Geophysical Fluid Dynamics Institute. 相似文献
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We report experiments on the flow of two fluids of contrasting viscosity through a pipe in which low-viscosity fluid occupies the center of the pipe. The volume flux of the low-viscosity fluid in the pipe increased during an experiment but did not reach 100% in most cases. The transition from high- to low-viscosity-dominated outflow involved a drop in pressure gradient and an increase in flow rate due to reduced viscous resistance in the pipe. Initially, the central flow was thin and parallel-sided, but as its diameter increased the flow became unstable. A sequence of instabilities was observed during the course of each experiment, both in time and as a function of height in the pipe. In the most commonly observed instability the central flow adopted a helical geometry. The transition from parallel-sided to unstable flow first appeared at the top of the pipe and propagated downwards against the flow. Axisymmetric instabilities originating at the pipe entrance were also observed. All forms of instability exhibited entrainment of viscous fluid into the faster moving central flow. Entrainment was extensive early in the existence of the central flow, but later on the volume flux of lower-viscosity fluid in the central flow rose more rapidly than the rate of entrainment and the proportion of lower-viscosity fluid increased with time. These compositional changes determined the viscosity of the central flow which was found to control its diameter and velocity. In banded pumice deposits, silicic pumice without mafic component is commonly erupted alongside banded pumice blocks. We infer that banded pumice may correspond to the central flow in our experiments, i. e., that viscous magma has been incorporated into less viscous melt, and that pure acid pumice is derived from the outer flow. Changes in eruption style may be caused by variations in pressure gradient and flow rate due to changes in the viscosity of the melt in the conduit. Varied mafic/silicic proportions and degree of mixing in magmatic associations are controlled by the bulk volume erupted, discharge rate, initial temperature difference and aspect ratio of the conduit. 相似文献
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The propagation of stress waves in a large-diameter pipe pile for low strain dynamic testing cannot be explained properly by traditional 1D wave theories. A new computational model is established to obtain a wave equation that can describe the dynamic response of a large-diameter thin-walled pipe pile to a transient point load during a low strain integrity test. An analytical solution in the time domain is deduced using the separation of variables and variation of constant methods. The validity of this new solution is verifi ed by an existing analytical solution under free boundary conditions. The results of this time domain solution are also compared with the results of a frequency domain solution and fi eld test data. The comparisons indicate that the new solution agrees well with the results of previous solutions. Parametric studies using the new solution with reference to a case study are also carried out. The results show that the mode number affects the accuracy of the dynamic response. A mode number greater than 10 is required to enable the calculated dynamic responses to be independent of the mode number. The dynamic response is also greatly affected by soil properties. The larger the side resistance, the smaller the displacement response and the smaller the refl ected velocity wave crest. The displacement increases as the stress waves propagate along the pile when the pile shaft is free. The incident waves of displacement and velocity responses of the pile are not the same among different points in the circumferential direction on the pile top. However, the arrival time and peak value of the pile tip refl ected waves are almost the same among different points on the pile top. 相似文献
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Behaviour of rare earth elements during hydrothermal alteration at the Buena Esperanza copper-silver deposit, northern Chile 总被引：1，自引：0，他引：1
A study of the REE behaviour in alteration zones of the Buena Esperanza subvolcanic CuAg deposit, located in the Coastal Range of northern Chile, reveals that the elements are mobile in the rocks during alteration. The ore-forming process developed in three different stages of alteration-mineralization.
The hydrothermal alteration of the early and middle stages affected basaltic fragments of a breccia pipe. La and Ce were leached from the rock fragments located at the bottom and at the middle part of the breccia pipe and partly redeposited at the top during alteration. Sm, Eu and Tb were released selectively and the heavy REE behaved as relatively immobile elements. Sericite is the most important alteration mineral for fixing the REE during this stage. The incoming fluids had low REE contents.
The late stage of hydrothermal alteration happened simultaneously with the intrusion of a gabbroic volcanic neck, affecting mainly these subvolcanic rocks. REE patterns of samples from the top and bottom of the alteration zone exhibit roughly parallel trends, but are systematically enriched in REE in comparison to unaltered samples. This enrichment seems to be more intensive at the top of the altered area coinciding with the enrichment of Rb, K and Cu in these rocks. Epidote plays the most important role for fixing this hydrothermal input of REE during the latest stage of alteration. 相似文献
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在安装福州地震台TJ-2型体积式应变仪过程中,发现存在钻孔选点与观测室分开考虑等问题,提出一些建议。井孔注水试验结果揭示,该井孔探头顶部可能存在一个与探头近距离的含水层干扰。初步对气压、水位、降雨影响进行分析。 相似文献