考虑围岩流变特性的地震尖点型突变模型

Instability of fault earthquake in rheological media and cusp catastropho

考虑到断层两盘围岩的粘弹性和断层的应变弱化 ,建立了断层地震的简化力学模型 ,首先证明了该模型对应于尖点突变 ,然后利用尖点突变理论研究地震的非稳定机制 ,阐明只有当外界对系统输入足够的能量 ,且刚度比小于 1时 ,系统内的能量才能迅速地转移与释放 ,引起地震。

Considering the strain weakness behavior of fault and the visco elasticity of surrounding rocks. A simple mechanical model for fault earthquake is put forward. First, the equivalency between the model and cusp catastrophe is proven. Then, the cusp catastrophe theory is applied to analyse the instability mechanism of the fault earthquake. It is explicated that the quick transferring of energy and the violent releasing of energy dont take place unless the enough energy from external world is input into the mechanical system and the stiffness ratio is less than unit. The period of seismogeny is both related to the period of loading owing to distant field displacement and to the visco elasticity behavior of surrounding rocks.