Hydrochemical changes of a spring due to the May 30, 2014 Ms 6.1 Yingjiang earthquake, southwest China

Liying Chen; Guangcai Wang

doi:10.1016/j.envpol.2021.117125

Hydrochemical changes of a spring due to the May 30, 2014 Ms 6.1 Yingjiang earthquake, southwest China

Environ Pollut. 2021 Sep 1:284:117125. doi: 10.1016/j.envpol.2021.117125. Epub 2021 Apr 17.

Authors

Liying Chen¹, Guangcai Wang²

Affiliations

¹ 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.
² 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. Electronic address: wanggc@pku.edu.cn.

PMID: 33906040
DOI: 10.1016/j.envpol.2021.117125

Abstract

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 Ca²⁺, Mg²⁺ and HCO₃^- 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 Ca²⁺ and HCO₃^- reversed from Ca²⁺ excess to HCO₃^- excess, probably resulting from a relatively decreased Ca²⁺ 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.

Keywords: Carbonate spring; Co-seismic; Hydrochemical processes; Ion concentrations; Post-earthquake.

MeSH terms

China
Earthquakes*
Environmental Monitoring
Groundwater*
Water Pollutants, Chemical* / analysis
Water Quality

Substances

Water Pollutants, Chemical