新疆阿克陶MS6.7地震引起的新10井水位同震响应研究

Coseismic response of water level in Xin10 well caused by MS6.7 Akto, Xinjiang, earthquake

  • 摘要: 本文根据新10井数字化高频采样水位仪记录到的2016年11月25日新疆阿克陶MS6.7地震所引起的水震波,对比分析了该井水位与地表垂向运动的相关性特征,并对二者与井-含水层系统水文参数的关系进行了深入探讨.分析结果显示:①与地震波信号相似,新疆阿克陶MS6.7地震引起的新10井水震波存在两个显著的周期,即6—10 s和15—30 s;②新10井水震波响应幅度与地表垂向运动幅度整体呈正相关,且在高频阶段(频率大于0.08 Hz)二者的振幅比随着频率的减小而增大,表明该井水位对周期大于12 s的信号放大效能较高;③利用水震波与地震波的振幅比估算新10井观测含水层渗透系数的量级为10-2 cm/s,且在地震波作用过程中含水层的水文参数也存在波动.本研究表明,井水位的同震响应机理较为复杂,在分析水位同震响应特征时,高采样率的水位数据是获得可靠结果与认识的基础.

     

    Abstract: A hydroseismogram induced by the Akto MS6.7 earthquake in Xinjiang on November 25, 2016 was recorded by digital high frequency sampling level gauge. We comparatively analyzed the correlation characteristics between the water level and the vertical ground motion, and the relationship between the above two and the hydrological parameters of well-aquifer system was carried out by a thorough discussion. The results suggested that: ① similar to the seismic signal, there are two significant periods, 6--10 s and 15--30 s in the hydroseismogram of Xin10 well induced by the Akto MS6.7 earthquake. ② overall, the response amplitude of hydroseismogram in Xin10 well was positively correlated to the amplitude of vertical ground motion, and the amplitude ratio of the two increased with the reduction in frequency at high frequency (greater than 0.08 Hz), which indicated that the water level of Xin10 well could enlarge signals with period more than 12 s more effectively. ③ permeability coefficient of Xin10 well-aquifer system was estimated at about 10-2 cm/s by using the amplitude ratio of the hydroseismogram and seismic waves, and the hydrogeological parameters in aquifer also fluctuated during the process of seismic wave action. The results in this paper also showed that the coseismic response mechanism of well water level is more complicated, and high sampling rate of water level data is the guarantee to obtain reliable results and knowledge in coseismic response of water level analysis.

     

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