关键词: 地下流体, 正常动态, 震前异常, 三峡井网

Abstract: This paper presents the results of analysis of observed data of water levels from 8 observation wells, water temperature from 4 wells and soil radon from 4 well sites obtained during the year of 2001. Based on the work, the normal behaviors of each observation item are established and their responsibility to earthquake event are tested. The results indicate that all the groundwater levels from 8 wells are able to reflect the solid tide. The sensitivity of the response of groundwater to volumetric strain of the earth crust in eight wells ranges from 10^-9 to 10^-10 volumetric strain/mm. Groundwater levels in most wells within the well network have barometric effects and are influenced to some extent by the rainfall. The water temperature in 4 wells is relatively stable, the daily change of which is ranging within several degrees a thousandth. The soil radon in 4 well sites fluctuates dramatically, and the annual change ranges from ten to several tens Bq/L. The anomalies of water levels in 6 wells, water temperature in one well, and soil radon in one well site were observed before the M_L3.6 earthquake occurred at Meijiahe, Zigui County on October 16, 2001. This may indicate that the Three Gorge observation well network has a relatively high capability to respond earthquake event.

Key words: subsurface fluids, normal behaviors, seismic anomaly, Three-Gorge well network