摘要
针对地震前后离子浓度异常变化成因以及机理等问题,以不同条件下(温度、粒度、时间),不同岩石(灰岩、橄榄岩、花岗岩)的水-岩反应为研究对象,利用控制变量与偏最小二乘法对反应后溶液中Na^(+)、K^(+)、Cl^(-)、SO_(4)^ (2-)、Ca^(2+)、Mg^(2+)的变化进行研究,并与地震台站水化学观测数据进行对比。结果表明:随着温度升高,Na^(+)、K^(+)、SO_(4)^ (2-)浓度分别增加到初始溶液的363%、188%、147%。粒度对溶液离子浓度的影响十分明显,随着粒度减小,岩石与水接触面积增大,Na^(+)、K^(+)、Cl^(-)、SO_(4)^ (2-)浓度都明显增加。随着反应时间的增加,Na^(+)、K^(+)、Cl^(-)、SO_(4)^ (2-)浓度也出现增加的趋势。以上研究表明:水-岩反应接触面积是影响离子浓度的主要因素,含水岩层在构造应力作用下破裂,导致水-岩反应接触面积改变,可能是地震前后水化学短临异常的重要成因机制之一。
Water-rock reaction experiment, which can simulate the subsurface temperature and pressure environment, is an effective way to study the formation mechanism of hydro-chemical anomalies related with the earthquake.This paper, focusing on the issues such as the formation mechanisms and the cause of the abnormal changes in ion concentrations before and after the earthquake, taking the water-rock reactions of different rocks(limestone, peridotite, and granite)under different conditions(temperature, particle size, and time)as the study object, studies the changes of Na^(+),K^(+),Cl^(-),SO_(4)^ (2-),Ca^(2+),and Mg;in the solutions after the reactions using the controlled variables and the partial least squares.Compared with the hydro-chemical data from seismic stations, the results show that Na^(+),K^(+),and SO_(4)^ (2-) respectively increase to 363%,188%,and 147% of the initial solution with increasing temperature.The particle size affects dramatically the ion concentration of the solution;as the particle size decreases, the contact area between the rock and the water increases, and the ion concentrations of Na^(+),K^(+),Cl^(-),and SO_(4)^ (2-) all increase significantly.An increasing trend of Na^(+),K^(+),Cl^(-),and SO_(4)^ (2-) ion concentrations is also observed as the reaction time increases.The results indicate that the contact area of the water-rock reaction is the main factor affecting the ion concentrations.Therefore, the rupture of water-bearing rock formation under the action of tectonic stress, resulting in the change of water-rock reaction contact area, may be one of the important formation mechanisms for the short and impending hydro-chemical anomaly before and after the earthquake.
作者
邵俊杰
李营
孙凤霞
陈志
刘雷
徐超文
胡乐
路畅
刘兆飞
赵元鑫
SHAO Junjie;LI Ying;SUN Fengxia;CHEN Zhi;LIU Lei;XU Chaowen;HU Le;LU Chang;LIU Zhaofei;ZHAO Yuanxin(Institute of Earthquake Forecasting,China Earthquake Administration,Beijing 100036,China)
出处
《地震研究》
CSCD
北大核心
2022年第2期187-198,共12页
Journal of Seismological Research
基金
现代化建设试点(2021IEF1205)
任务项目(2021IEF0704)
“抓大震”科技支撑(2021IEF0707)
河北省省级科技计划(20545401D)
中国地震局预测重点实验室自主课题(2017KLEP03)联合资助。
关键词
高温高压
水-岩反应
水化学异常
high temperature and high pressure
water-rock reaction
hydro-chemical anomaly
