本文从观测事实出发,给出了四次唐山强余震前地震活动变化的某些特征。结果表明,强余震前,唐山地震序列的频度,地震波能量,b值及震中分布图象都发生了显著变化。通过讨论认为,这些变化是由于强余震发震断层形成闭锁段引起的,因此与强余震的孕育有着密切联系,可作为前兆信息。 Based on the observations, this paper presents some characteristics of the seismic activity changes before the Tangshan strong aftershock. The results show that before the strong aftershocks, the frequency of Tangshan earthquake sequence, the seismic energy, the b value and the distribution of the epicenter have all changed significantly. According to the discussion, these changes are caused by the formation of a latching section of a strong aftershock fault, so it is closely related to the occurrence of strong aftershocks and can be used as precursor information.