As the Liaogu-1 well is located in a special tectonic zone with good hydrogeological condition

continuous and reliable observations have been performed resulting in a wealth of valuable data of seismic observations

which indicate that anomalous variations of hydrochemical elements serves as a good precursor to earthquakes with M≥5.0 occurring in the range of 500 km around the well.Based on integrated analyses of the seismic precursors of hydrochemical elements in the Liaogu-1well since the observation began in January

1981

the characteristics of hydrochemical elements are investigated as well as their forming mechanism and predictive significance as the seismic precursors from seismic source and tectonic field.Based on the above studies

we have also analyzed lower anomalous changes of total quantity of gases released from the Liaogu-1 well from May to October 2003

and achieved a satisfactory result in the test of earthquake prediction.