STATISTIC CHARACTERISTICS OF XINFENGJIANG RESERVOIR EARTHQUAKE SEQUENCE

The seismic activity characteristics of Xinfengjiang reservoir earthquake sequence and the relationship between them and the water level changes of the Xinfengjiang reservoir are studied in this paper. The result shows that the low b value period of the earthquake sequence is related to the enhancing of regional seismic activity and to some extent,the earthquake sequence can be seen as a seismic activity window of Southern China.Studies of 55earthquake subsequences with main shock of M_L≥3.5 indicate that the b value of the subsequence after 1975 are distinctively lower than that of the before,60 percents of the earthquake subsequences belongs to mainshock-aftershock type,the biggest aftershocks of 78percents of the earthquake subsequences occur with 2 days after the main shock.There is no distinctive linear relation between the enhancing of seismic activity and water level rising of Xinfengjiang reservoir,instead,73 percents of the M_L≥4.0 earthquakes occurs during the unloading period of Xinfengjiang reservoir.