论地震序列的一种可能的重要成因

本文在Asperity模式和Barrier模式的基础上,提出了另外一种不均匀体模式——障碍体模式,并对该模式进行了数值模拟的研究。结果除证实了我们以前做过的单轴压力下模拟障碍体的实验结果以外,还表明在含有障碍体的断层面上,破裂的扩展与破裂的传播速度、始破裂区域的大小、裂纹的类型以及障碍体所在断层的介质有关。在有围压的情况下,破裂可以先越过或绕过强度较高或尺度较大的障碍体,经一段时间的应力积累过程后,再使障碍体发生破坏。本文通过对震源区中障碍体的性质和影响的研究,解释了海城和邢台两个地震序列形成和发展的可能原因,得到一些较为合理的结果。

ON A POSSIBLE IMPORTANT GENESIS OF EARTHQUAKE SEQUENCE

Based on the Asperity model and the Barrier model, another heterogeneous model-Obstacle model is proposed in this paper. The research of numerical modelling is taken for this model. The results show that on the fault plane where there are obstacles, the rupture expansion is related to the spreading speed of rupture, the area of initial rupture, crack types and the medium of the fault which contains obstacle. It also verifies that the rupture can cross or detour higher strength or/and bigger size obstacles, and then makes obstacle fracture again after a period of stress accumulation process under the condition of confining stress. Besides, it also proves the experiment results of imitated obstacle under uniaxial compression which we took before.The possible genesis of the Haicheng and Xingtai earthquake sequences are explained, and some reasonable consequences are made through the research of the properties and effect on obstacle in earthquake source area.