临界慢化期限与地震短临预报

CRITICAL SLOW CHANGE TIME LIMIT FOR SHORT AND IMPENDING EARTHQUAKE PREDICTION

lug慢化是统计物理学中的一个概念,即当一种相态向另一种相态突变之前,那种在旧相系统中出现的带有向新态转变的分散的涨落现象,不仅量值增大了,而且涨落的持续时间也拉长了。这种时间的拉长就叫做慢化。系统越接近突变的临界状态,这种慢化愈显著。对于大地震来说,在临近大震孩们练应力保持态为旧相,大洋动放为新相。在由旧相向新相转变的时候,会出现小释放态的涨落。如果这种小释放态的涨落加剧,最后演变为大释放阶段,则此时旧相完全转变为新相。

Critical slow change is used as one of the concepts in statistic physics. It refers to a kind of scattered fluctuation phenomenon that first occurred in the old phase system but then turned into a new state just before the sudden change from one phase to another when its values increased and duration lengthened. This lengthened time is called slow change. The closer phase system to the critical state of sudden change, the more obviousness this kind of slow change appeared. To a great earthquake,the high stress state impending great shock is called old phase,the large release period is called new phase. And there might be a small fluctuation of release state appeared during the period of phase change,such as the concave-convex plane on the surface of the focal fault becoming weakening before large earthquake, and the harmonic motion of pre-displacement and the adjusting elements on the two ends of the focus caused by the strain pre-release in the focus region ,etc.. If this kind of small fluctuation of release state is getting larger and larger,finally it evolves into the stage of great release,then the process from the old phase to the new one is completed. In this paper,some precursory critical slow changes before large earthquakes have been used to discuss the index of short-term and impending prediction for large earthquakes.