共查询到18条相似文献，搜索用时 140 毫秒
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分析合肥地震台钻孔体应变观测资料干扰因素及特征,发现水位和气压等因素对TJ-Ⅱ型钻孔应变仪影响显著.在该地震台观测优化改造期间,钻孔体应变受到临近钻孔灌水的影响,而降雨和灌水导致的水位变化,对体应变干扰程度不同. 相似文献
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《地震地磁观测与研究》2015,(4)
对连云港地震台钻孔体应变2009年1月—2013年12月数字化观测资料与气压、水位、降雨的影响进行相关分析,并进行潮汐因子M2波、周日波变化分析,获得地震前形变临震异常特征。结果表明:1气压变化以短周期正相关干扰为主,在时间上表现为准同步变化;体应变和水位变化具有较好的准同步性;降雨过程、降雨量及降雨时间等与体应变密切相关;2当地下介质性质发生变化时,固体潮发生畸变,潮汐因子变化可作为取得地震前兆的有效途径之一。 相似文献
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本文通过四分量自检、相对标定内精度分析对东平地震台YRY-4钻孔分量应变观测资料进行可靠性分析，并结合滑动相关性计算、潮汐因子内精度对2套仪器数据进行了对比，证明YRY-4钻孔分量应变2面应变相关性高，相关系数接近1，相对标定内精度高，与体应变数据整体趋势一致。2套仪器观测环境一致，运行稳定，数据正常可靠，但也存在降雨、场地干扰特殊时段曲线表现不一致的情况。针对2种特殊情况结合相关性计算、S变换进行了对比分析。结果表明，降雨时段，因钻孔条件差别较大，2套仪器数据相关性较差，接近0；场地干扰时段，2套仪器观测系统均受到影响，频率域同步出现干扰信号，影响数据曲线形态及潮汐因子精度，但2套仪器面应变相关性达0.91。综合分析，东平台钻孔应变仪与体应变2套仪器观测系统是可靠稳定的。 相似文献
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利用昭通中心站YRY-4钻孔应变仪前兆观测数据资料,提取降雨对该仪器观测数据的干扰事件,采用降雨总量、瞬间最大值降雨量两类降雨分类统计方法,定量分析降雨对观测数据产生的影响。结果表明:当降雨总量达到40 mm、瞬间最大值降雨量大于0.4 mm时,YRY-4钻孔应变仪观测数据受降雨干扰明显;当降雨总量大于40 mm时,降雨总量与观测数据应变量呈线性关系,瞬间最大值降雨量与降雨总量之间无显著的对应关系。分析认为,降雨干扰影响主要来自降雨渗透和台站周边地质抗水体荷载量大小两个方面。定量分析降雨干扰,有利于区分异常与干扰,积累经验,以便于及时对有效异常进行判定,为地震研究服务。 相似文献
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INFLUENCE OF PUMPING ON FOUR-COMPONENT BOREHOLE STRAIN AT TAI'AN SEISMIC STATION AND ITS INTERFERENCE MECHANISM 
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下载免费PDF全文 JIA Yuan GAN Wei-jun LI Jie ZHU Cheng-lin YIN Hai-tao LU Shuang-ling JU Jia-bin 《地震地质》2019,41(6):1429-1443
Four-component borehole strainmeter (FCBS) is one kind of high-precision borehole strain observation instruments invented in China. As a kind of near-surface deformation observation instrument, FCBS is also easily disturbed by the external environment factors. As a common factor, pumping has significant influence on FCBS observation. Existing studies mostly identify the pumping interference from the perspective of observation curve morphology, relatively few studies focus on its interference mechanism. In order to truly capture earthquake precursor information, it is necessary to study the interference mechanism. In recent years, RZB-3 type FCBS at Tai'an seismic station has been seriously affected by pumping, so it is necessary and also feasible to study the interference mechanism of pumping. Since the influence of pumping interference on borehole strainmeter is common, this work would be very practical and be used for reference by other borehole strain observation stations.
We find that the original observation curves and observed surface strain, shear strain from RZB-3 type FCBS at Tai'an seismic station have the characteristics of synchronous change with the borehole water level, in which the linear correlation coefficient between the two observed shear strain curves and borehole water level reached 0.70 and 0.82 respectively. We further find that the principal strain direction of borehole and borehole water level after normalization meet the nonlinear function as y=1.217arctan(x)0.224-0.284. The above phenomenon indicates that the observation of RZB-3 type FCBS at Tai'an seismic station is significantly affected by the borehole water level, and the influence is more obvious and the gradient is larger at the stage of low water level. Pumping interference often appears in low water level stage and changes the rock pore pressure state. Statistics show that pumping interference affects the borehole strain state.
To investigate the interference mechanism of pumping to RZB-3 type FCBS at Tai'an seismic station, we take a known pumping as an example, in which we study the principal strain state of the borehole in three periods of normal pumping, interruption of pumping and resuming pumping respectively. During each period, we solve 3 parameters of the principal plane strain state, i.e. the maximum principal strain rate, the minimum principal strain rate and the maximum principal strain direction from four observation equations of FCBS by nonlinear iterative least squares algorithm. On the other hand, concentrated load model (CLM) is used to simulate the mechanical mechanism of pumping. Firstly, the depth of FCBS relative to pumping source and the concentrated load at pumping source are inversed, then, the strain state surrounding the pumping well, including the state at RZB-3 borehole, is simulated by forward modeling. By comparing these results, we find that:
(1)The concentrated load at pumping source inversed by CLM during periods of normal pumping and resuming pumping are both located at or near the bottom of the pumping well, which is consistent with the actual situation, indicating that mechanism and degree of the influence of pumping on borehole strain are well simulated by CLM.
(2)The observed strain state is consistent with the simulation result of pumping interference by forward modeling, indicating that the principal strain state of borehole calculated based on observation of FCBS reflects the true strain state of borehole under different pumping states.(3)The inversed concentrated load at pumping source during pumping periods is significant greater than the load of the pumped water, indicating that the pumping process has more significant influence on the pore pressure of rocks than the load of the pumped water.
Even though CLM is an approximate simulation since it's based on some elastic assumptions, the interference mechanism of pumping on RZB-3 type FCBS at Tai'an seismic station is well explained, which is maybe very helpful for studying the influence of pumping interference on other deformation instruments, locating the unknown pumping source and studying the characteristics of pore pressure of rocks. 相似文献
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昌平台Sacks体应变仪观测曲线年变现象成因研究 总被引：3，自引：0，他引：3
本文系统地研究了北京昌平台Sacks体应变仪观测曲线年动态变化的基本规律，结合井水位、抽水和降雨等实际观测资料，分析后认为，台站附近农田机井季节性抽水和地下水的自然补给是造成体应变年变现象的根本原因，并探讨了体应变与井水位的定量关系和物理机制，同时对地震预测中所关心的“破年变”问题也进行了探讨。 相似文献
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《Journal of Geodynamics》2010,49(3-5):115-119
Tides and barometric pressure variations cause pore pressure changes in the solid earth. In boreholes which are hydraulically connected to confined aquifers these pore pressure changes can be observed as water level variations. In case of confined aquifers boreholes can be regarded as volumetric strainmeters. From June 2004 until May 2005 a large scale injection experiment was realised in the pilot borehole (4000 m) at the German Continental Deep Drilling (KTB) site in Bavaria. During this test the injection induced deformation was observed by a tiltmeter array around KTB consisting of five tiltmeter stations at horizontal distances from 1.6 to 3 km from the injection borehole. At each station the local groundwater level was observed in depths between 30 and 50 m. The pore pressure was recorded in the boreholes. The time series were checked for tidal signals and injection influence. The injection was not verified presumably due to the fact that the penetration of the injected water was controlled by local geology and tectonic faults zones. Although the boreholes extending only to shallow depth tidal signals are clearly observable in at least two of five stations. On December the 26th 2004 the Sumatra–Andaman earthquake occurred which is clearly detectable in the pore pressure variations at all five stations. 相似文献
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Introduction The surface of the Earth is the main location where the fluid strongly interacts with solid, and where the atmosphere, hydrosphere, biosphere, and lithosphere strongly interact. Obviously, fault zones as the channels of fluid (water) flow are the focus area of this strong interaction. Earth-quakes, as the products of tectonic activity, occurred near or on the fault zones, can be regarded as one of the results of this strong interaction. Bolt (1999) pointed out that if there were … 相似文献
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本文从时域和频域分别对福州台和永安台的体应变和井水位资料观测的一致性进行了分析，并对其力学机制进行了深入探究，在此基础上阐明了二者观测一致性的物理含义.时域内的分析结果显示:福州台体应变与井水位的相关系数为0.7939，钻孔系统的灵敏度为0.0558 mm/10-9，井水位与体应变观测曲线十分相似；永安台体应变与井水位的相关系数为-0.7543，钻孔系统的灵敏度为-0.0005 mm/10-9，井水位与体应变曲线呈镜像对称，这表明两台站的井水位与体应变观测高度相关，且二者的相位滞后近似为零.在频域内，分别对福州台2012年3—5月及永安台2014年3—5月的井水位和体应变资料进行维尼迪柯夫调和分析，分别获取半日波、全日波数个波群的逐月潮汐因子和相位滞后，并计算得到了钻孔系统的灵敏度和井水位相对于体应变的相位滞后.结果表明，3个月中大多数波群的灵敏度十分相近，而且与时域内所得年周期低频分量的灵敏度较接近，但相位滞后误差较大，这可能与采用反正切公式计算相位滞后受计算误差影响有关，即非线性的反正切公式对计算误差具有放大累积效应，因此相位滞后应以时域分析所得接近于零的结果为准.综上，时域和频域的分析结果表明，福州台和永安台的井水位对体应变的响应基本上是线性时不变的，二者观测一致性的根本原因在于两台站的承压含水层井水位观测系统基本上是满足叠加性、齐次性和时不变的物理可实现因果系统. 相似文献