Coseismic response characteristics of groundwater temperature and level of Yunnan well network to several earthquakes

Abstract

Based on the coseismic response data of water temperature and water level of 26 observation wells in Yunnan well network from 2008 to 2023, the coseismic response characteristics of water temperature and water level of each observation well were compared and analyzed with 8 earthquakes that have a significant impact on Yunnan region. The coseismic response mechanism was discussed from the perspectives of seismic wave energy density, lithology, control of fault zone and dynamic coordination. The results indicate that the response of water temperature and water level in the well pattern of Yunnan to the far-field earthquakes is more significant than near earthquakes, with the response primarily concentrated in the middle of Yunnan. The water level exhibits a more pronounced response than the water temperature. The coseismic variation of water level is mainly characterized by oscillation and rise, while the water temperature is mainly characterized by pulses. Dehong Fapa Dian No.22 well and Lijiang Xiangshan well have better seismic reflection performance in Yunnan well pattern. On the other hand, No.06 well in Jianchuan, No.01 well in Huize Gangou Dian, Xiaoshao well in Kunming Guandu District, Dayao geothermal well, and Nanhua Zhen 2 well exhibit weaker coseismic responses compared to the other 21 wells. Further analysis shows that the linear fitting correlation coefficient between seismic wave energy density and epicenter distance is greater than −0.9, which is significantly negative correlation and positive correlation with magnitude, and shows the corresponding relationship between energy density and permeability coefficient. Finally, we analyzed the mechanism of coseismic response of water temperature and water level.

Keywords

• yunnan well network
• water temperature
• water level
• coseismic response