China Earthquake Networks Center, Beijing 100045, China.
Int J Environ Res Public Health. 2022 Sep 22;19(19):12004. doi: 10.3390/ijerph191912004.
Springs offer insight into the sources and mechanisms of groundwater recharge and can be used to characterize fluid migration during earthquakes. However, few reports provide sufficient annual hydrochemical and isotopic data to compare the variation characteristics and mechanisms with both atmospheric temperature and seismic effects. In this study, we used continuous δH, δO, and major ion data from four springs over 1 year to understand the groundwater origin, recharge sources, circulation characteristics, and coupling relationships with atmospheric temperature and earthquakes. We found that (1) atmospheric temperatures above and below 0 °C can cause significant changes in ion concentrations and water circulation depth, resulting in the mixing of fresh and old water in the aquifer, but it cannot cause changes in δH and δO. (2) Earthquakes of magnitude ≥ 4.8 within a 66 km epicentral distance can alter fault zone characteristics (e.g., permeability) and aggravate water-rock reactions, resulting in significant changes in δH, δO, and hydrochemical ion concentrations. (3) Hydrogen and oxygen isotopes are the most sensitive precursory seismic indicators. The results of this study offer a reference for the establishment of long-term hydrochemical and isotopic monitoring, with the potential for use in earthquake forecasting.
泉水为地下水补给的来源和机制提供了深入的了解，可用于描述地震期间的流体迁移。然而，很少有报道提供足够的年度水化学和同位素数据来比较大气温度和地震效应的变化特征和机制。在这项研究中，我们使用了四个泉水中连续的 δH、δO 和主要离子数据，为期一年，以了解地下水的来源、补给来源、循环特征以及与大气温度和地震的耦合关系。我们发现：（1）0°C 以上和以下的大气温度会导致离子浓度和水循环深度的显著变化，导致含水层中新鲜水和老水的混合，但不会导致 δH 和 δO 的变化。（2）距离震中 66 公里范围内的 4.8 级及以上地震会改变断裂带特征（如渗透率），加剧水岩反应，导致 δH、δO 和水化学离子浓度的显著变化。（3）氢和氧同位素是最敏感的地震前兆指标。本研究结果为建立长期水化学和同位素监测提供了参考，有望用于地震预测。
