Hydrochemical characteristics of hot spring waters in the Kangding district related to the Lushan <i>M</i><sub>S</sub> = 7.0 earthquake in Sichuan, China

Abstract

Abstract. Hydrogeochemistry of 10 hot springs in the Kangding district was investigated by analyzing cation and anion concentrations in the spring water. The water samples were collected in the 5 days after the Lushan M S = 7.0 earthquake, which occurred on 20 April 2013. The spring waters are classified into seven chemical types based on their hydrochemical compositions. Compared with hydrochemical data before the Lushan earthquake, concentrations of Ca 2+ , HCO − 3 and total dissolved solid (TDS) in water samples from the Guanding, Erdaoqiao, Gonghe, Erhaoying, Tianwanhe and Caoke springs significantly increased, which may be the result of a greater increase in groundwater from carbonate rocks, and water-carbonate rock interactions, enhanced by the increment of CO 2 . Concentrations of Na + , Cl − and SO 2− 4 in water samples from the Guanding, Zheduotang, Xinxing and Gonghe springs decreased, indicating a dilution of shallow waters. Concentrations of Na + and SO 2− 4 in water samples from the Erhaoying spring water increased, which may be attributed to water-granite interactions enhanced by H 2 S. The results indicated that hydrochemical components of spring water could be used as an effective indicator for earthquakes.

Hydrogeochemical Characteristics and Conceptual Model of the Geothermal Waters in the Xianshuihe Fault Zone, Southwestern China

“…Geothermal springs are primarily found in the Yalabamei, Zhonggu, Erdaoqiao, and Yulingong geothermal areas of the XFZ (Figure 1c). Up to now, previous studies have interpreted the genesis of geothermal springs in the Erdaoqiao and Yulingong geothermal areas using geophysical and geochemical methods [16][17][18][19][20][21][22][23][24]. However, only a few previous investigations analyzed the geothermal springs in the Yalabamei and Zhonggu geothermal areas [25], and thus the conceptual model of the geothermal system is unclear.…”

Hydrogeochemical Characteristics of Hot Springs and Their Short-Term Seismic Precursor Anomalies along the Xiaojiang Fault Zone, Southeast Tibet Plateau

“…Specific conductance, pH, dissolved oxygen, and temperature were measured in well water using a multiparameter probe inserted into a flow-through cell closed to the atmosphere, and in springs by lowering the probe into the spring vent for in situ measurements. The concentrations of cations (K + , Na + , Mg 2+ , and Ca 2+ ) and anions (F − , Cl − , Br − , NO 3 − , and SO 4 2− ) were measured by a Dionex ICS-900 ion chromatograph and an AS40 automatic sampler at the Earthquake Forecasting Key Lab of China Earthquake Administration, with the reproducibility within ±2% and detection limits 0.01 mg/L [43]. The HCO 3 − and CO 3 2− concentrations in the hot springs were measured by the 0.05 mol/L HCl titration 0.1% methyl orange and 1% phenolphthalein procedures with a ZDJ-100 potentiometric titrator (reproducibility within ±2%).…”

Hydrogeochemical characteristics and genesis of Seismic observation wells in Shandong Province

“…The CO 3 2and HCO 3 concentrations were measured by standard titration procedures with a ZDJ-100 potentiometric titrator. For calibrating the chromatography, standard samples were measured before and after measuring each batch of water samples, with the deviation of the measurements within ±2% (Chen et al, 2015). The data were evaluated by the ion balance (Woith et al 2013).…”

“…The study of seismogenic mechanism shows that the material migration, energy release and stress evolution in the deep earth are accompanied by the abnormal variations of physical and chemical parameters of groundwater and the concentrations of escaping gas. Anomalies of underground uids responded sensitively to the medium changes in seismogenic and peripheral areas , being closely related to the regional tectonic activities (Che et al,1997(Che et al, ,1999Liu et al,1999;Zarrocaet al,2012;Sano et al,2017;Chen et al, 2015Chen et al, ,2018Kumar et al,2020). The underground uid, bringing abundant information about the physical and chemical evolution in the earth's interior, re ecting the development process of earthquakes, and providing reliable earthquake precursors,is an effective and promising research medium for earthquake monitoring and prediction (Igarashi et al,1995;Koizumi et al,2004;Gresse et al,2016;Menzies et al, 2016).It is hydrophysical observations of the water level, water temperature and ow rate of seismic observation wells that provide valuable basic data for quantitative research on the coupling relationship and spatio-temporal variation rules among the stress eld, energy eld and seepage eld (Wang et al, 1999;Montgomery et al, 2003;Ren et al,2004).…”