前言 本文着重探讨了1970年以来大华北地区(东经105°—124°;北纬30°—43°)的十次六级左右和六级以上强震前的地震活动特点和有预报价值的信息。我们之所以选取大华北地区,是因为该区不但人烟稠密,而且地震活动有自己的特点。又因1970年以来的小地震资料远比历史小地震资料丰富和可靠,故只选用了这段时间的地震资料。为了避免 Preface This paper focuses on the characteristics of seismic activity and forecasting values ​​before the MS10-6 and above MS6.0 in the Greater North China (105 ° -124 ° E; latitude 30 ° -43 ° N) since 1970. The reason why we chose the Greater North China Region is because it is not only densely populated but also has its own characteristics. Since the data of small earthquakes since 1970 are far more abundant and reliable than those of historical small earthquakes, only the seismic data of this period were selected. in order to avoid