刘序俨, 杨锦玲, 王紫燕, 张清秀, 刘水莲, 陈小云. 2017: 福建省井水位与体应变观测一致性分析. 地震学报, 39(3): 395-406. DOI: 10.11939/jass.2017.03.009
引用本文: 刘序俨, 杨锦玲, 王紫燕, 张清秀, 刘水莲, 陈小云. 2017: 福建省井水位与体应变观测一致性分析. 地震学报, 39(3): 395-406. DOI: 10.11939/jass.2017.03.009
Liu Xuyan, Yang Jinling, Wang Ziyan, Zhang Qingxiu, Liu Shuilian, Chen Xiaoyun. 2017: Analyses on the consistency between well water level and bulk strain in Fujian Province. Acta Seismologica Sinica, 39(3): 395-406. DOI: 10.11939/jass.2017.03.009
Citation: Liu Xuyan, Yang Jinling, Wang Ziyan, Zhang Qingxiu, Liu Shuilian, Chen Xiaoyun. 2017: Analyses on the consistency between well water level and bulk strain in Fujian Province. Acta Seismologica Sinica, 39(3): 395-406. DOI: 10.11939/jass.2017.03.009

福建省井水位与体应变观测一致性分析

Analyses on the consistency between well water level and bulk strain in Fujian Province

  • 摘要: 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.

     

    Abstract: The observation data of the bulk strain and underground well water level at Fuzhou and Yong'an seismic stations were investigated in both time domain and frequency domain for the consistency analysis. Besides, the mechanical mechanism of the borehole system was explored so as to demonstrate the physical meaning of the phenomenon. The results indicate that the bulk strain is highly correlated with water level in the time domain. The correlation coefficient between the bulk strain and well water level at Fuzhou station is 0.7939, and the sensitivity of borehole system is 0.0558 mm/10-9. The well water level shows consistent tendency with bulk strain at Fuzhou station. The correlation coefficient between the bulk strain and well water level at Yong'an station is -0.7543, and the sensitivity of borehole system is -0.0005 mm/10-9. The peak and valley of water level change correspond uniformly to the peak and valley of bulk strain at Fuzhou station respectively; whereas variation of the water level has negative correlation with variation of the bulk strain at Yong'an station. The results imply that the water level responds synchronously to the bulk strain at the two stations and the phase lag is approximately zero. In the frequency domain, three months observation data were utilized to obtain the monthly group factor and phase lag of the semidiurnal and diurnal tidal waves by the Venedikov harmonic analysis method. From the sensitivity and phase lag of the borehole system, it is clear to see that the sensitivity of most wave groups are not only close to each other, but also close to the sensitivity of annually periodic change obtained in the time domain, whereas with large phase lag variances. Considering the uncertainties of the phase lag obtained by arctangent, the phase lag value close to zero in the time domain should be more reliable. All in all, the results from both time and frequency domains demonstrate that the observation of well water level and bulk strain are consistent at Fuzhou and Yong'an stations. The main reason lies in the confined aquifer borehole observation system of the two stations which in principle meets the physical requirements of the superposition, homogeneity and time invariance. Therefore, it is concluded that the borehole system at Fuzhou and Yong'an stations is linearly invariant in time.

     

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