THE ANALYSIS OF DATONG-YANGGAO EARTHQUKE SEQUENCE OF OCT.1989 BY SEISMIC DATA FROM ZHANGJIAKOU STATION

A group of moderately strong earthquakes has occured in Datong-Yanggao area since Oct. 18 1989. This sequence, of which the characteristics are different from that of the earthquakes occured before in the same area, belongs to main shock-swarm type. It is characterized by either main shock-after shocks type or swarm type. It occured which initially includes several moderately strong events and was followed by the rapid attenuation of seismic enerage with strong after shock periodic fluctuation. We have made an analysis by using the seismic data of Zhang Jiakou station after the Datong-Yanggao main shock. The results have shown that the correct analysis for the characteristics of the earthquake sequence by sufficient single station data is of great significance for in situ seismic monitor and prediction.