为了探索地震活动的复杂性和预报大震发生的可能性,本文以信息论和多重分形观点,在实验室条件下研究了岩石(大理岩、辉长岩和沙岩)声发射和某些大地震(海城、唐山和龙陵)发生前、后地震活动的一阶信息维D_1,初步结果表明:岩石失稳破裂前和大地震发生前均有一个降维过程,在此期间确定D_1的曲线都有较长的无标度区,特别,临近岩石失稳和大震发生前,无标度区有变窄的现象,显示出系统有相当不稳定的临界行为。 In order to explore the complexity of seismic activity and predict the possibility of large earthquakes, this paper studies the acoustic emission of rocks (marble, gabbro and sandstone) and some large earthquakes Haicheng, Tangshan and Longling), the first-order information dimension D_1 of the seismic activity before and after the occurrence of the earthquake shows that there is a dimension reduction process before the rock failure and before the earthquake, during which the curve of D_1 There is a longer scale-free zone, in particular, near the rock instability and before the occurrence of a large earthquake, the phenomenon of scale-free zone narrowing, showing the system has a rather unstable critical behavior.