【摘要】 1970年通海地震序列与1976年唐山地震序列的对比表明,两次地震的余震衰减,余震强度和频度,余震分布区的形状等有区别。对此提出了一种解释:若余震分布区域的长轴长度a与短轴长度b之比a/b越大,则震源体越接近于一个面,在一个面上进行的调整过程应当比较简单,余震的衰减比较快,强余震比较少而小;反之则震源体越表现出一个体的形态,在一个体内进行的调整过程应当比较复杂,余震衰减比较慢,强余震比较多而大。对于那些在主震后能够很快进行定位并勾画出余震区域轮廓的情况,可以尝试利用a/b快速判断后面强余震的多少以及余震衰减的快慢。更多还原

【Abstract】 Comparison of the seismic sequences between Tonghai earthquake in 1970 and the Tangshan earthquake in 1976 indicates that the attenuation,number,intensity of aftershocks and shape of epicenter areas were different.In this paper,an interpretation is proposed that aftershocks reflect the adjustment process of the medium in seismic source after severe fracture.If the radio(a/b)from major axis length a and minor axis length b of the aftershock epicenter area is large,it implies the source volume being near to a plane and the adjustment process at the plane should be simple,so the aftershock attenuation is faster and strong aftershocks are less.In opposite case,with small a/b,the source volume is near to a cubic and the adjustment process is more complicated,so the aftershock attenuation is slower and strong aftershocks are more and stronger.It can be attempted to use the parameter a/b to estimate quickly that it the stronger aftershocks will be more or not,and the aftershock attenuation will be slow or not for the case that the aftershocks can be located immediately after the mainshock.更多还原