Abstract: Salt water layer is a kind of special aquifer in the coast region of north China plain. Observations and practices for many years indicate that the groundwater regime of salty water layer has strong earthquake reflecting capacity. Panzhuang well is a salty water observation well, the groundwater regime is normally stable and daily rangeability is less than 10 centimeter. For years this well has showed anomalies of water level obviously before earthquakes in Capital Region of China especially the Tangshan area. In May 2010, the abrupt increase anomaly of water level in this well was close to 3 meter. We need to scientificly determine that the anomaly is caused by other factors of interference or the earthquake preparation. Through the investigation and the analysis on the environment, well depth measurement, pumping tests and water quality testing, we conclude that the anomaly is caused by pipe aging, corrosion, leakage and shallow high salinity water infiltration in the well, and it is irrelevant to the earthquake preparation or tectonic activity.

Key words: Water level anomaly, Anomaly analysis, Panzhuang well in Tianjin