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.