研究前震序列的活动规律及其与一般小震群的区别,对于研究地震孕育过程及地震预报都是有益的。为此,我们处理了我国近十几年来资料较详细的17个地震,发现其前震活动是在主震前较早时间就开始的,它与波速变化似有某种对应关系。选择主震前适当的时间间隔,其中的前震频数一般随时间接近主震而按指数增长。并且,大地震的一个4级以上前震与一般小震群中的同量级地震发生前的应变释放速率是不同的。 Studying the activity law of the pre-earthquake sequence and its difference from the general small swarm are helpful for the research on the earthquake breeding process and the earthquake prediction. For this reason, we have processed 17 more detailed earthquakes in our country over the past decade and found that the foreshock activity started earlier than before the main shock, and it seems to have some correspondence with the changes in the wave velocity. Select the appropriate time interval before the main shock, in which the front shock frequency generally close to the main shock with time and exponentially. Moreover, the magnitude of the strain release before a magnitude 4 earthquake of a large earthquake is different from that of a typical small earthquake swarm.