Abstract: Though visible groundwater anomalies have been noticed in wells and springs before and during earthquakes for thousands of years, it has been proven that precursory groundwater anomaly occurring before some earthquakes may not appear prior to some others; on the other hand, precursory groundwater anomaly which occurred at previous earthquakes appears newly in some areas but may not accompany with new earthquakes. It shows that the relation of groundwater anomalies to earthquakes is complex. Seismic groundwater regime monitoring is aimed at acquiring groundwater physical and chemical changes and providing basic information for studies on the relation of groundwater to earthquakes. Monitoring is not only a technique but also a kind of science. Some scientific and technological issues such as monitoring network optimization need to be further studied. It remains difficult to identify seismic precursor from groundwater anomalies and to link groundwater anomalies with earthquakes temporally and spatially.

Key words: groundwater regime, groundwater anomaly, coseismic response, monitoring, earthquake