State Key Laboratory of Biogeology and Environmental Geology & MOE Key Laboratory of Groundwater Circulation and Environmental Evolution, China University of Geosciences, Beijing, 100083, China; School of Water Resources and Environment, China University of Geosciences, Beijing, 100083, China.
State Key Laboratory of Biogeology and Environmental Geology & MOE Key Laboratory of Groundwater Circulation and Environmental Evolution, China University of Geosciences, Beijing, 100083, China; School of Water Resources and Environment, China University of Geosciences, Beijing, 100083, China.
Environ Pollut. 2021 Sep 1;284:117125. doi: 10.1016/j.envpol.2021.117125. Epub 2021 Apr 17.
Groundwater chemistry can be affected by and related to earthquakes, thus it is crucial to understand the hydrochemical changes and associated processes caused by earthquakes for post-seismic groundwater utilization. Here we reported the major ion concentrations changes of the Ganze Spring in response to the May 30, 2014 Ms 6.1 Yingjiang earthquake, southwest China based on the daily time series (from 1st January 2012 to 20th July 2014) of Ca, Mg and HCO concentrations, as well as data of bulk strain and Peak Ground Velocity (PGV) recorded at a nearby station. The results showed that the entire hydrochemical response process can be divided into two stages after the earthquake occurred: 1). decline stage which was characterized by an increasingly decline of the three ion concentrations, indicating a gradually significant dilution effect. At first, the relationship of molar concentrations of ions showed no obvious changes; but later as the rate of decrease in ion concentrations increased, the relationship between Ca and HCO reversed from Ca excess to HCO excess, probably resulting from a relatively decreased Ca contribution from dissolution of gypsum and dolomite due to dilution in mixing water. 2). recover stage when the ion concentrations recovered gradually with relatively lower values than that at pre-earthquake, revealing the reduction of dilute water inflow. In combination with the bulk strain and PGV data, the study suggested that major ion concentrations changes are attributed to dilution effect due to new fracture creation or unclogging/clogging of fractures triggered by the earthquake. The results could enhance the understanding of earthquake induced water chemistry changes and could have implications for water resources management and security in tectonically active areas.
地下水化学受地震影响，并与地震有关，因此了解地震引起的地下水利用后水文化学变化和相关过程至关重要。这里我们根据 Ganze 泉每日 Ca、Mg 和 HCO 浓度时间序列（2012 年 1 月 1 日至 2014 年 7 月 20 日）以及附近台站记录的体应变和峰值地面速度（PGV）数据，报道了中国西南 2014 年 5 月 30 日 Ms6.1 盈江地震对 Ganze 泉主要离子浓度变化的响应。结果表明，地震发生后，整个水化学响应过程可分为两个阶段：1）下降阶段，其特征是三种离子浓度逐渐下降，表明稀释效应逐渐显著。起初，离子摩尔浓度之间的关系没有明显变化；但随着离子浓度下降速度的增加，Ca 和 HCO 的关系由 Ca 过剩转为 HCO 过剩，可能是由于混合水中稀释作用使石膏和白云石溶解的 Ca 贡献相对减少。2）恢复阶段，离子浓度逐渐恢复，但值相对低于地震前，表明稀释水的流入减少。结合体应变和 PGV 数据，研究认为，主要离子浓度的变化归因于地震引发的新裂缝形成或裂缝疏通/堵塞的稀释效应。研究结果可加深对地震引起的水化学变化的认识，对构造活动区水资源管理和安全具有重要意义。
