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EARTHQUAKE ›› 2021, Vol. 41 ›› Issue (1): 93-115.doi: 10.12196/j.issn.1000-3274.2021.01.008

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Hydrogeochemical Characteristics of Gongyihai Hot Spring, in Shimian County, Sichuan Province

SHI Hong-yu, WANG Wan-li, ZHOU Xiao-cheng, YAN Yu-cong, LI Peng-fei, JIANG Li, CHEN Zhi   

  1. Key Laboratory of Earthquake Prediction, Institute of Earthquake Science, CEA, Beijing 100036, China
  • Received:2020-02-04 Revised:2020-04-24 Online:2021-01-31 Published:2021-01-28

Abstract: It is of great significance to judge the short impending fluid anomaly of the moderate-strong earthquake.By using hydrogeochemical data, the hydrologic cycle model of hot springs was established to explore the relationship between hydrogeochemical changes and earthquakes in hot spring. The spatial-temporal variations of groundwater chemical types and their genesis were discussed by measuring ion concentration, trace element, hydrogen and oxygen isotopic compositions and Strontium isotope in the Gongyihai fault zone in Sichuan Province. From October 2008 to September 2019, 206 water samples were collected from Gongyihai hot spring in the Gongyihai Fault zone, and their hydrogeochemical characteristics were investigated. The results show that ① Hot spring water samples are Na-HCO3·Cl types. Stable isotope values (-108.67 ‰~-110.47 ‰ and -14.19 ‰~-14.83 ‰) distributed near the atmospheric precipitation line, indicating that the hot spring water mainly points to a meteoric origin; ② SiO2 (42.7 mg/L) values of the geothermal water indicated that those spring water was followed by interaction between water and rock during circulation with a probable mix of earth's surface water, and the circulation depth of hot spring was about 4.3 km; ③ Pre-earthquake anomaly, coseismic response and post earthquake anomaly in three MS5.0 earthquakes within the scale 300 km in hot spring fluids, through the mobile observation of the study area. Gongyihai hot spring is located at the intersection of Gongyihai fault zone and Anninghe fault zone, the surrounding earthquakes will influence the ion concentration changes of Gongyihai hot spring. Therefore, a hydrogeochemical model was proposed for the geochemical system on the basis of the geochemical data of hot springs combined with the geology and hydrogeology of the study area. These are of great significance to the short-term fluid anomaly judgment of future moderate and strong earthquakes around the Gongyihai fault zone.

Key words: Hot spring, Isotope, Hydrogeochemistry, Earthquake, Shimian

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