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本文应用固体物理学中位错所受自由面的像力的概念来讨论调整单元(自由面或软弱介质)对孕震震源地区断层的蠕裂、临震前锁住段断层中预位移的传播以及地震发生时裂缝的失稳传播的影响。推导了几种不同形状的自由边界对螺型位错和刃型位错作用的像力的表达式。以直立倾滑断层为例求出了震源地方断层某一段发生相对位移时由于自由面的像力作用而在断层上引起的附加应力场。估算了实际断裂情况下此附加应力场的数量级。认为像力的作用在震源过程中尤其是在研究对大震的触发作用时是不可忽视的。从像力的观点出发解释了地震发生时的一些现象。
In this paper, we use the concept of free surface force suffered by dislocations in solid state physics to discuss the influence of the adjustment unit (free surface or weak medium) on the propagation of pre-displacement in the fault section before earthquakes As well as the impact of the instability of cracks on earthquakes. The expressions of the image force of the screw free dislocation and the edge dislocation effect of several free shapes with different shapes are derived. Taking the upright slip-slip fault as an example, the additional stress field induced on the fault due to the free-form image force is obtained when the relative displacement of a certain section of the source local fault occurs. The order of magnitude of this additional stress field is estimated for the actual fracture case. It is considered that the function of image force can not be neglected in the process of hypocenter, especially when it is used to study the triggering effect on large earthquakes. From the viewpoint of force, we explain some phenomena when an earthquake occurs.