[1]SHAO Junjie,LI Ying,SUN Fengxia,et al.Experimental Study of the Characteristics of Ion Concentration Changes during Water-rock Reaction and Its Implication to the Formation of Seismic Anomalies[J].Journal of Seismological Research,2022,45(02):187-198.[doi:10.20015/j.cnki.ISSN1000-0666.2022.0018]
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Journal of Seismological Research[ISSN 1000-0666/CN 53-1062/P] Volume:
45
Number of periods:
2022 02
Page number:
187-198
Column:
Public date:
2022-05-20
- Title:
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Experimental Study of the Characteristics of Ion Concentration Changes during Water-rock Reaction and Its Implication to the Formation of Seismic Anomalies
- Author(s):
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SHAO Junjie; LI Ying; SUN Fengxia; CHEN Zhi; LIU Lei; XU Chaowen; HU Le; LU Chang; LIU Zhaofei; ZHAO Yuanxin
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(Institute of Earthquake Forecasting,China Earthquake Administration,Beijing 100036,China)
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- Keywords:
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high temperature and high pressure; water-rock reaction; hydro-chemical anomaly
- CLC:
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P315.724
- DOI:
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10.20015/j.cnki.ISSN1000-0666.2022.0018
- Abstract:
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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-,SO2-4,Ca2+,and Mg2+ 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 SO2-4respectively 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 SO2-4all increase significantly.An increasing trend of Na+,K+,Cl-,and SO2-4ion 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.