Annual variation characteristics of georesistivity at Zhouzhi geoelectric station, Shaanxi Province

Based on the vertical electric soundings of Zhouzhi geoelectric station, the effects of groundwater and rainfall on georesistivity are qualitatively simulated by finite element analysis. Meanwhile, the long-term and short-term effects of rainfall on the NS- and NE-direction georesistivity are also analyzed by the convolution function. The results show that the annual variation of georesistivity at Zhouzhi geoelectric station is mainly caused by the seasonal variation of the surface resistivity, and has little relationship with the groundwater level. The effects of rainfall on the NS- and NE-direction georesistivity are consistent with the georesistivity observations and show a tendency to increase after rain for a short time, while display a negative correlation with the long-term observations. According to the qualitative simulation results， this reversed change is mainly due to the deepening of penetration depth. All these analyses are consistent with the observations, providing a reference to understanding the annual and abnormal variations of georesistivity at Zhouzhi geoelectric station.