## 6 Conclusions  
In this study, the geochemical characteristics analysis of thermal waters and gases collected along the MDF leads to the following conclusions:  
* The hydrogen and oxygen isotope values of the springs in the STS area reveal that the thermal springs primarily originate from atmospheric precipitation and melting snow of the Tianshan Mountains, with a distinct altitudinal effect. The analysis of water chemical types indicates that cold springs are mainly of the Ca-HCO\({}_{3}\) and Ca-Mg-Cl types, while thermal springs are of the Na-HCO\({}_{3}\) and Na-Cl types. The circulation depth of the springs range from 477 to 4772 m, suggesting that shallow water bodies  
Figure 10: Conceptual model of fluid circulation in the study area. undergo deep circulation along the fault zone and react fully with the surrounding rocks, carrying a wealth of deep information. * The higher \({}^{3}\)He/\({}^{4}\)He ratios (0.42 Ra and 3.71 Ra) in the thermal spring gases indicate that the mantle-derived helium proportion at S1 is as high as 46.48%, suggesting active deep fluid migration and potential geothermal or tectonic activity in the intersection area of the TFF and MDZ. In contrast, the gases at S13 mainly originate from the crust, showing a lower mantle contribution and weaker tectonic activity. The high Poisson's ratio at S1 is associated with the enrichment of deep fluids and intense tectonic activity, while the low Poisson's ratio at S13 reflects the rigidity of the crust and limitations in fluid enrichment, with the gas source primarily being a mixture of shallow crustal gases and gases from the decomposition of organic matter. * There is a close relationship between seismic activity and the distribution of thermal springs in the study area. The consistency between seismic density and intensity and the distribution of thermal springs suggests that seismic activity may influence the hydrogeological characteristics of the thermal springs. Monitoring shows ions and isotopes anomalies, along with trace elements fluctuations, linking seismic events to hydrogeochemistry. These findings highlight the potential of hot spring water chemistry as a valuable precursor for seismic activity, providing critical insights for earthquake forecasting and hydrothermal system dynamics. * The impact of seismic activity on the hydrochemical characteristics of thermal springs is complex and variable. The widespread influence of the Wushi \(M_{S}\)7.1 earthquake on the groundwater system indicate that the relationship between seismic activity and fluid anomaly response is regulated by a combination of stress field characteristics, fault locations, and fluid migration pathways, rather than a simple positive correlation with earthquake magnitude. * This study not only deepens the understanding of the hydrogeochemical characteristics of the groundwater in the STS area but also provides valuable data support for the study of groundwater response mechanisms before and after the Wushi earthquake, revealing the complex interaction between seismic activity and the groundwater system, which has significant scientific implications for earthquake prediction and geological disaster assessment. However, due to the limited spatial and temporal coverage of the sampling, certain short-term and localized hydrochemical responses may not have been fully captured. Even so, the results provide a valuable foundation for future studies on fault-fluid interactions and seismic precursors. * The following supporting information can be downloaded at: [[https://www.mdpi.com/article/10.3390/app15094791/s1](https://www.mdpi.com/article/10.3390/app15094791/s1)]([https://www.mdpi.com/article/10.3390/app15094791/s1](https://www.mdpi.com/article/10.3390/app15094791/s1)), Table S1: Data of fluid geochemical components in the study area; Table S2: Continuous monitoring data of S13 major ions and isotopes; Table S3: Continuous monitoring data of S13 trace elements. * Conceptualization, J.L. and M.H. ; methodology, J.T. ; software, Y.W. ; validation, Y.Y., H.Y. and B.Y.