First , let us take the history record of activities of the earthquakes on the mainland as the sample of statistics to analyze the distribution characteristics of the mainland earthquakes in both time and space . it shows that no matter we take the mainland as a whole to study , or take the mainland as two sections ( the east and the west ) , even take the activities of the earthquakes in a certain region to study , the mainland activities occur in cluster in both time and space . that is to say there is a clear objectivity in the characteristic of the activities of the strong mainland earthquakes - group activity 首先，以中国大陆地区历史地震记录为统计样本，对大陆地震在时间和空间上的分布特征进行统计，表明，无论是把我国陆区作为一个整体来研究，还是把我国陆区分为东西两区来研究，乃至取某一个地区的区域地震活动性来研究，大陆地震活动在时间和空间上呈成组性丛集活动特征，即中国大陆强震成组活动的特性具有鲜明的客观性。
First of all , it determines the scope in which earthquake might be genetated , the potential seismic sources areas and the upper limit of the earthquake magnitude through the analysis , research and evaluation of the area seismic geological condition of the workzone . secondly , according tothe research of the seismic activity , it also determines the seismic activity coefficients for per potential seismic sources areas , and the delay relation of seismic intensity and seismic accelaration , and then three different seismic intenstities and dynamic strength of bedroch under different probability are given . through the analysis and caculation of earthquake hazard with the analytic approach of probability 首先，对工作区的区域地震地质环境进行了分析、研究、评价，确定了莱芜市可能发生地震的范围、潜在震源及其震级上限等。其次，根据对地震活动性的认识，确定了各潜在震源区的地震活动性参数及莱芜市地震烈度和地震加速度衰减关系，在此基础上用概率分析法对莱芜市地震危险性进行了分析计算，得到了莱芜市在三种不同概率水平下的地震烈度和基岩地震动强度。
“ the fact is that many main shocks do not occur " suddenly " : 10 - 30 % of them are preceded by foreshocks during the week before their occurrence ; some are preceded by year - long pre - activity9 ; some are preceded by increased moment release during the years before them10 - 14 , and some are preceded by seismic quiescence15 - 17 “事实是，许多主震并非‘突然’发生主震中的10 - 30 %之前在发震之前的一周有前震；有的主震前有长达一年的震前活动性34 ；有的在震前有数年的加大的瞬间释放3536373839 ，有的则在震前出现地震活动性的静止404142 。
