Abstract: The completion of digital transformation of the precursor observation network in China has widened the frequency range for extracting related information of earthquake preparation and removing disturbance effects from groundwater, and make it possible for reviewing some of the previous knowledge. In this paper, we pick out 10 stations with high quality water level and barometric pressure data from the Center for Earthquake Precursory Observation Network of China, analyzed the spectrum characteristics and correlation of groundwater level, barometric pressure and earth tide of each station from Jan.1 to May 11, 2008, and discussed the time-lapse of groundwater to barometric pressure. It shows that the response of groundwater level to barometric pressure in moderate to high frequency band is not as good as that in the low frequency band and their correlation decreases with the decline of periods; and the lithologic characters of the well-aquifer systems has a great impact on the response characteristics of groundwater level to barometric pressure and earth tide in moderate to high frequency band. In several limestone wells, there exists abnormal response characteristics of groundwater level to barometric pressure in high frequency band. The time-lapse of groundwater level to barometric pressure has little effect on the overall response characteristics, reflecting the complexity of the two signals themselves.

Key words: Groundwater level, Barometric pressure, Earth tide, Response characteristics, Frequency band