THE SHORT-TERM VARIATION OF WATER LEVEL IN A WELL LOCATED AT KAIYUAN, YUNNAN BEFORE EARTHQUAKE OCCURRENCES

The Kaiyuan Well is situated at the intersection of the Xiaojiang fault and the Oujiang Fault. Six intrmediate earthquakes of magnitudes Ms4.6 occurred in the surrounding regions during the last ten years. On the basis of the results of analysis of the relevant data, it is found that the water level of the well before any one of those earthquakes of Ms4.6 corresponds to an ascension and interpreted as stress enhancement in the course of development of the earthquake source.