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大震前地下水位异常与应力异常区 总被引：2，自引：0，他引：2
利用井口水位对潮汐应力的响应，分析了含水层对强震孕育过程中应力变化的响应。结果显示，当含水层的瞬时应力变化值大于临界值时，水位的异常图像为阶变形态；当含水层的瞬时应力变化值小于临界值，但某一时段的累计值大于临界值时，水位的异常图像为缓变形态。而水位异常图像出现的上升或下降形态，取决于井孔含水层系统在大震孕育过程的应力调整再积累阶段所处的构造部位。水位震前异常的特征，源于地震孕育过程中应力异常区的形成。 相似文献
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分析研究了承压含水层应力应变与井水位变化之间的定量关系,得出了井水位变化与含水层应力应变之间的定量关系公式,给出了利用承压井水位变化反演含水层应力变化的两种新方法。利用大同地震前后井水位变化资料,反演了该地震前后大区域应力场的动态调整变化,并形成了时间与空间的演化图像。利用这些图像分析了大同地震前后大区域应力场的动态调整变化特征与可能的机制。 相似文献
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利用水位阶变资料反演震时应力的调整变化 总被引：6，自引：0，他引：6
本文利用我国在日本秋田地震时有水位阶变的65口井孔的观测资料,计算了地震时引起我国应力场的调整变化,应力变化量值从8.7—6.4×10~4Pa。并分析了我国应力场调整时,应力增加区和应力降低区交替出现的可能原因。 相似文献
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研究了分析了井水位变化与含水层应力应变之间的定量关系,给出了利用承压井水位变化反演含水层应力变化的新方法,利用唐山地震前后井水位变化资料,反演了地震前后大区域应力场的动态调整变化,形成了时间与空间的演化图象,分析了唐山地震前后大区域应力场的动态调整变化特征。 相似文献
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水井水位的气压效率和降水荷载效率之间的定量关系 总被引：2，自引：0，他引：2
本文以完全弹性介质为基础,从弹性理论和地下流体动力学理论导出承压井气压效率和降水荷载效率之间的定量关系。并从弹性理论出发推论得出:气压应力通过含水层上覆地层向含水层传递时,应力的衰减是次要的,可以忽略的。也就是说,在一般气压这样小的变化范围内,水井含水层对气压变化的响应,可以用完全弹性介质来描述它。 相似文献
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大华北地区应力场在汶川地震时的变化研究 总被引：1，自引：1，他引：0
利用大华北地区在汶川8级地震时有水位阶变的31口并孔的观测资料,通过计算各井水位系统的观测格值,进而估算了震时引起大华北地区应力场的调整变化.研究发现汶川地震后大华北中部地区的压应力得到增强,大华北东部和南部地区则表现为应力降低,对未来大华北地区的地震危险性预测应具有一定参考价值. 相似文献
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The present paper shows analysis of water level (the distance from the land surface to the water in the well under static condition) and water temperature observed at three different levels of Chuan no. 03 well to study the changes associated with the Wenchuan earthquake of 2008 and the 2011 Tohoku-Oki earthquake. Our analysis shows co-seismic changes in water level and water temperature associated with the increase in compressive stress associated with the Wenchuan earthquake. The water level shows an increase, whereas there was drop in water temperature at the shallow depth (395 m) and enhancement of water temperature at the middle (595 m) and the bottom (765 m) layers. However, no step change in water level or temperature of Chuan no. 03 well is observed associated with the Tohoku-Oki earthquake, only seismic wave propagation-induced water level oscillation and led to co-seismic response of water temperature. The analysis of the co-seismic responses and post-earthquake adjustment processes combined with the borehole histogram and the borehole temperature gradient data clearly show co-seismic changes in water temperature that could be closely associated with the changes in the regional stress and strain state and the distribution of the aquifer and the characteristics of the aquifer. The observed temperature variation of different layers in the borehole is likely to be controlled by the flow of water in the horizontal direction. 相似文献
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远场大震的水位、水温同震响应及其机理研究 总被引：19，自引：0，他引：19
深井水温观测在中国已经开展了20年,但目前对于水温响应机理的研究还不充分。在对2004年12月26日印尼苏门答腊MS8.7地震后,中国地下流体观测井网中121个观测井水位、水温同震响应特征的研究中,作者发现了具有规律性的一类变化类型:当某些观测井水位出现振荡的时候,其同井水温绝大多数会出现几十分钟到数小时的下降—恢复过程。为了对此现象进行验证,又收集了河北唐山矿井2001年数字化以来39次远场大震水位、水温的同震响应资料,发现其具有相同的规律。在对可能造成水温下降的影响因素研究分析的基础上,提出了同震水温下降的气体脱逸模式,给出了在气泡脱逸过程中造成水温下降的2种主要影响因素,并利用此模式对部分观测现象进行了较合理的解释 相似文献
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The large scales of co-seismic water level changes in mainland China were observed in response to the tragic 2008 Ms 8.0 Wenchuan earthquake. To better understand the mechanism of these hydrogeological phenomena, groundwater-level data at 17 confined wells, with an epicentral distance of <500 km, were collected. We compare the static strain predicted by dislocation theory with the volumetric strain calculated by the tide effect of the groundwater based on poroelastic theory. The results show that the sign of the co-seismic groundwater level change is consistent with the sign predicted by dislocation theory. Additionally, the magnitude of the strain calculated by the two methods is also concordant in half of the wells. In the rest of the wells, the strains inversed from the groundwater level are one or two orders of magnitude larger than the fault dislocation model. These wells mostly have an epicenter distance larger than 300 km; therefore, the dynamic stress induced by the seismic wave may be responsible for the co-seismic water level changes in these wells. According to these results, we roughly estimate that the effect range of the static stress is approximately 300 km for the Wenchuan earthquake, and the dynamic stresses dominate beyond this epicenter distance. In addition, geological and hydrogeological conditions and other mechanisms may be responsible for these changes. 相似文献
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大地震引起了左家庄和宝坻(相距～50km)两井中截然不同的同震水位响应.我们用水位的气压和潮汐响应来分析解释此现象.结果表明,宝坻井的观测含水层中存在页岩,且此井受裂隙影响很大,储水效应较差.页岩的复杂裂隙或者各向异性可能会导致此井观测含水层处于半封闭状态,从而导致垂直向排水的发生.通过多方计算分析后,我们将这两口井划分为两种模型—1.水平流动模型;2.水平流动+垂直流动的混合流动模型.由于裂隙影响,宝坻井的观测含水层介质与外界的水力沟通性在震前就较强(震前渗透率就比较大),所以宝坻井观测含水层与外界的孔隙压差异较小,导致同震渗透率上升较小甚至没有变化,这些因素是导致该井同震水位变化幅度总是非常微小的原因. 相似文献
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Chen Daqing 《中国地震研究》2007,21(3):333-344
The observation of water temperature in deep wells has been carried out for more than 20 years in China.However,study on the mechanism of water temperature response to earthquakes is inadequate.During the study of the co-seismic response characteristics of water level and temperature in 121 wells within the China subsurface fluid monitoring network at the time of the December 26,2004,M-S8.7 Indonesia earthquake,we found regular response characteristics,that is,when the water level in a deep well oscillates,the water temperature in the same well will mostly experience a cycle from dropping to restoration at the same time.The process will continue for dozens of minutes to several hours.In order to confirm the observed phenomenon,we collected the digital water level and temperature observation data for 39 far-field strong earthquakes from the Tangshan well in Hebei Province(with the data set beginning in 2001).The same response characteristics were observed.Based on the analysis of the influencing factors that may cause the water temperature drop,the authors suggest the gas escape mechanism for co-seismic water temperature drop and posit two main factors that influence the water temperature drop during the process of gas escape.Finally,the authors provide a rational explanation of some observed phenomena based on the mechanism. 相似文献
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通过对漾濞MS 6.4地震云南数字化井水位分钟值数据同震响应特征进行分析,分析观测仪器采样率对井水位映震能力的影响,并对水位同震响应机理进行初步分析。结果表明,对于漾濞MS 6.4地震,13口同震响应观测井主要分布在震中距200 km范围内的红河断裂带北侧和小滇西地区;同震响应形态可分为阶升（上升）型、阶降（或缓降）型、阶变（阶升、阶降）—复原型等3种变化类型,阶升型同震响应幅度相对大于其他2种类型;由漾濞MS 6.4地震烈度长轴和短轴共同划定的椭圆区域来划分此次地震静态应力和动态应力的影响范围,可以从各观测井受力状态初步分析水位同震响应变化形态的力学机理;在静态应力影响范围内,井水位同震响应主要表现为阶升变化;在静态应力影响范围以外,除以阶变（阶升、阶降）—复原变化为主外,还有阶降（缓降）、阶升变化。观测仪器采样率对井水位映震能力的影响较大,水位秒钟值数据的同震响应变化形态更加完整,但目前水位秒钟值数据的收集和使用都还在不便之处,这种情况有待改进。 相似文献
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为深入理解井水位同震响应机理，本文开展了向完整井-松散含水层系统输入由不同频率和振幅（加速度）组成的正弦波荷载的振动台实验。以实验模型为物理模型，建立了振动作用下松散承压含水层中孔隙水压力响应的流固耦合模型和含水层水流与井流的相互作用模型，并运用多物理场耦合模拟软件COMSOL Multiphysics对实验过程进行了数值模拟。实验中观测到的四种典型水位变化形态与野外场地同震井水位变化形态相似。数值模拟结果显示，本研究建立的数学模型能较好地反映松散承压含水层中孔隙水压力和水位的响应情况。本文研究对解释地下水同震响应机制、岩体渗流稳定性和安全问题具有重要意义。 相似文献
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系统研究了宁夏地震地下水观测井网中7口国家井的井水位固体潮效应。对7口井的观测资料进行了调和分析,给出了各井孔井水位固体潮主要潮汐波的潮汐参数。利用湖汐参数计算了各井孔含水层的某些物理力学参数,并对各井孔井-含水层系统探测地壳内应力应变状态的能力及利用井孔潮汐效应进行地震预报等问题进行了探讨 相似文献