THE HYDROGEOCHEMICAL CHARACTERISTIC OF FLUORINE AND ITS RELATIONSHIP TO EARTHQUAKES IN CENTRAL HEBEI PROVINCE

The hydrogeochemical characteristics of Fluorine in central Hebei Province are studied, The results show that there is a positive correlation of Fluorine concentration to temperature and Co₂ concentration in groundwater, so, except for the igneous province with high Fluorine content, temperature and Co₂ concentration are the major factors affecting Fluorine concentration. Inaddition, Ca²⁺ content in groundwater can also influence the F^- concentration due to the low solution of CaF₂, only the groundwater with nigh Na⁺/Ca²⁺ ratio favours the enrichment of F^-. Finally, it is pointed out that the preperation process of earthquakes might result in the variation of F^- concentration, and the possible precursors before several earthquakes in Qianniu-6 and other wells are discussed.