Analysis of co-seismic response characteristics of the water level and water temperature at Tengchong center station to Myanmar M_S7.9 earthquake

On March 28, 2025, an M_S7.9 earthquake occurred in Myanmar. Significant co-seismic responses were recorded at most of the groundwater observation wells at Tengchong center station. By analyzing observational data of the water level and water temperature at Tengchong center station, the dynamic responses of groundwater during an earthquake were revealed. The results showed that the co-seismic response of the water level presented multiple forms, with three wells showing step-up changes, two wells exhibiting an oscillating response, and one well displaying oscillating characteristics after step-down, reflecting the pore pressure fluctuations and hydrodynamic exchange process caused by seismic waves. Although the water temperature response was mainly step-up and oscillating for most of the wells, the response signals of two other wells were weak, indicating that the thermal signal is less sensitive than the pressure signal to ground motion. Further analysis revealed that the co-seismic response abilities of the water level and water temperature observed at Tengchong center station differed significantly. The water temperature response was controlled by the heat exchange process of the water body, showing a lag of 1～2 minutes and complex recovery characteristics. The co-seismic response of the well water level was mainly restricted by the geological tectonic environment and hydrogeological conditions. By contrast, the water temperature response mechanism was more complex and involved the coupling of multiple factors, such as the seismic wave-induced hydrodynamic model, thermal convection effect, and sensor layout parameters. Our findings from this analysis of the co-seismic response characteristics of the water level and water temperature in the area provide a theoretical basis for the optimal layout of groundwater wells and identification of abnormal underground water signals.