【摘要】 用１９７２～１９９２年期间华北地区地震资料对地震危险度Ｄ值进行了空间扫描．结果表明，大部分中强以上地震前２～３ａ，在未来震中周围出现较大范围的Ｄ值中期异常区域．文中就Ｄ值用于中期预报的方法、预报效能、Ｄ值与实际地震活动的关系、计算结果的稳定性等问题进行了讨论更多还原

【Abstract】 The seismic data from 1972 to 1992 in North China are used in spacial scanning of seismic risk degree D value in this paper.The result shows that there are large anomaly zones of D value around the future epicenter about 3 years before most moderate strong earthquakes.In this paper,the method using D value in medium term earthquake prediction,prediction ability,the relation of D value to real seismicity and the stability of computation are also discussed.更多还原