【摘要】 在一次地震序列中主要的地震能量分两次释放的强震称双震型强震。本文对一九七六年龙陵、松潘、盐源三组双震型强震,从地震地质、余震分布结合前人模拟实验的成果和震源机制解的分析,对它们的成因机制作了探讨。认为由数条大断裂所围限的断块内部,当存在的规模相对较小的两组断层与最大主压应力轴的交角0均在30°—45°之间时(或θ在90°左右时),两组断层的破裂程度相近,或同时破裂,或略有先后,产生双震型强震。更多还原

【Abstract】 Those strong earthquakes,the main energy of which is released twice in one earthquake sequence are defined as strong double earthquakes.In the light of seismogeology,the fault plane solutions,the distribution of aftershocks and the previous simulation experiments,this paper makes a brief discussion on the genetic mechanism of three groups of strong double earthquakes,i.e.,Longling (May,1976),Songpan (Aug,1976),Yanyuan (Nov,1976) strong eartqhuakes,believing that in the middle of crust block formed by some large fault belts,and when there are two smaller faults as both of the angle of the fault and the axis of maximum principal compressional stress are 30°-45° or are 90°,the extent of fracture of these two faults is approximate or their fracture is simultaneous or in rapid succession hence the strong double earthquakes.更多还原