【摘要】 本文研究了华北最近地震活动期的三次强地震(邢台、海城、唐山)的余震序列,从实际观测资料与国内外的一些实验结果,提出余震震群的出现是在区域应力场增强的背景下余震区应力加强的效应。强震余震震群的起伏,可以作为监视华北地区中强以上地震孕育的“窗口”。文中以“多点场”观点讨论了余震震群与中强以土地震关系,认为强震与中强震在区域应力场中是处于支配与被支配的不同地位。更多还原

【Abstract】 We called all the higher frequency of aftershocks not keeping the aftershock decay rule is discussed and called an swarm of aftershocks.In this paper, the aftershock sequences of the three strong earthquakes located in Xingtai(邢台)、Haicheng(海城)and Tangshan(唐山)in the latest earthquake active period of Northern China are studied. From observed data and some experimints we consider that the aftershock swarm is the effect of the strengthened stress at aftershock region under the background of the strengthened regional stess field. the fluctuation of the aftershocks sequences of a strong earthquake can be regarded as a "window" from which the preparing process of a middling—strong or more earthquake in North China can be found and watched.The relation between the aftershock swarm and the middling-strong earthquakes is discussed from the view of "the field of more than one point", and consider the strong earthquake and the middling—strong earthquake are at dominating and being dominated situation in the regional stress field respectively。更多还原