A STUDY OF THE SCALE OF SEISMIC ACTIVITY IN WESTERN SICHUAN PROVINCE

This paper discusses the time-space variational characteristics of scale value H of the seismic activity before several moderately strong earthpuades in western Sichuan province. It is considered thatthere are high H value anomalies 1-2 years before strong esrthpuades. The spatial distribution of H values are related with geological structures, seismic zones, preparation process of strong earthquakes etc.We have studied the scale of regional seismic activity before several strtong earthquakes in.westernSichuam province by the formula produced by Luo Lange et al, and found that the H values became highfrom low ones before Luhuo 7.6, Song-Ping 7.2, Yanyuan 6.7 earthquakes and then the earthquakesoccurred. It is found by spatial scan result, that the scale value H of seismic activity showed an extensiveincreasing process before the Song-Ping 7.2 earthquake on August 16, 1976.