陕西甘肃宁夏三省(区)强震活动特点

根据对历史地震资料的分析研究，得出陕西甘肃宁夏三省（区）的强震活动特点是：①强震活动在时间上具有明显的不均匀性，即高潮期与低潮期的交替；②大震前中小地震分布的特点：地震空区分布、条带状分布、密集分布；③震中迁移；④强震活动的成带性；⑤大震的重复性。通过对地震活动特点和规律的探索，就能宏观判断目前地震活动的态势，从而预测未来几年至几十年的地震活动趋势。

CHARACTERISTICS OF STRONG EARTHQUAKE ACTIVITY INSHANXI-GANSU-N INGXIA AREA

According to the analysis of historic earthquak edata, thecharacterisitics of strong earthquake activity in this area are as follows:①the obviously uneven distribution of strong earthquake activities by time, i.e., the alternation of dense-occurrence period and quict period; ②blank area-forming, belting and dense distribution of medium and minor earthquakes before a strong earthquake; ③shifting of epicentre; ④belting distribution of strong earthquakes; ⑤repetition of strong earthquakes. By exploring the char acteristics and rules of seismic activities, the situation of seismic activity at the present time can be determined in general, and the tendency of earthquake activities in the tens of future years can be predicted.