汶川映秀地震台井孔逸出氢观测实验

Observational Experiment for Escaped Hydrogen from Wellboreat Wenchuan Yingxiu Seismic Station

为进一步认识汶川余震区破碎断裂带逸出氢的动态特征,选择位于北川—映秀断裂的映秀地震台观测井开展井孔逸出氢观测实验。实验数据显示:映秀台井孔逸出氢浓度较高,日变幅较大且具有明显的日变规律,呈现与气压变化同步及负相关的特征,日变形态与气温、水温、静水位相关性较小。通过不同仪器与采样方式进行观测实验,结果表明:映秀地震台井孔逸出氢浓度动态清晰、测值平稳,作为地震前兆观测地下逸出氢项目是可行的。

In order to further understand the dynamic characteristics of escaped hydrogen from the fractured fault zone in the Wenchuan aftershock region,we selected the observational hole(the Yingxiu Seismic Station)which located in the Beichuan-Yingxiu fault,and carried out the observation of escaped hydrogen from the wellbore.The experimental data show that the hydrogen concentration of the Yingxiu well is high,the daily variation amplitude is large and has obvious daily variation law,showing the characteristics of synchronous and negative correlation with the change of air pressure,the daily variation is less correlated with temperature,water temperature and static water level.Observational experiments by different instruments and sampling methods show that,the dynamic characteristics of hydrogen concentration escaping from the observation well at Yingxiu seismic station is clear and the measured value is stable,as an earthquake precursor,it is feasible to observe hydrogen escaping from underground.