珠江三角洲地震活动的若干特点

分析了二十世纪末30年来珠江三角洲地区地震活动的特征，认为珠江三角洲地区与东南沿海地震带在地震序列分布上总体趋势是一致的。在1970～1997年间，珠江三角洲地区b值滑动时间曲线从1984年起至1986年的高值异常可能是东南沿海地震带1986年开始的活跃幕的中期前兆。地震活动指数A(b)值曲线1988年及1994年的两处低值异常，则可能是本区1989年及1997年两个地震能量释放高峰的中期前兆。从本区及东南沿海地震带地震发生的时间进程上来看，本区很可能是东南沿海地震带区域应力场的调整单元。

Some characteristics of seismicity in the Pearl River Delta region

Based on studying the seismicity characteristics of the Pearl River Delta region for thirty years of the end of the 20th century,we think that the distribution of seismic sequence of the Pearl River Delta region coincides with that of the Southeast Coastal Seismic Belt on the overall trend. The high value anomalies, appearing on the b value slipping curve from 1984 to 1986 in the Pearl River Delta region, were likely to be the mid-term precursors of active episode of the Southeast Coastal Seismic Belt beginning from 1986.The two low value anomalies appearing on the curve of the seismicity exponent A(b) in 1988 and 1994 were likely to be the mid-term precursors of the flood tide of the seismic energy release in the area in 1989 and 1997. Looked the seismic anomalies in the area from 1970 to 1997 through by the time process of earthquakes occurring in the area and the Southeast Coastal Seismic Belt, the area is likely to be the adjustment unit of regional stress field of the Southeast Coastal Seismic Belt.