一个大地震发生之后常常伴随着一系列的余震。大量的余震引起了人们对它的注意。早在50年代,许多地震工作者就对余震进行了研究,其中有代表性的工作有: (1)李希特(C.F.Richter)1958年在《基础地震学》一书中就曾总结了余震空间分布的某些一般规律。如:余震震中范围呈椭圆形,其长轴常与活动断层平行,较大余震的震中常常集中于余震区的某一端,且常 A large aftershock is often accompanied by a major earthquake. A large number of aftershocks attracted people’s attention. As early as the 1950s, many earthquake workers studied aftershocks. Some of the representative work was as follows: (1) In 1958, CF Richter summarized aftershocks in Basic Seismology Some General Rules of Spatial Distribution. Such as: the epicenter of the aftershock was elliptical, its long axis often parallel with the active fault, the epicenter of a large aftershock often concentrated in one end of the aftershock area, and often