Abstract: The experimental study on transient processes of fracture and stick-stip instability shows that both of the stress drop and the displacement rise are not monotonous.They are oscillatory ones with multifrequencies.The SEM observation on fracture surfaces shows that the oscillation led to bilateral or multilateral traces.By combining the experimental results with the phenomena observed from natural fault surface and fault zone,such as slickensides,grooving,steps and abnormal array of subfaults,it has been presented that one of the reasons for the traces which reflect the bilateral or multilateral motions of natural fault may be the instability oscillation of fault from an event (earthquake).In contrast,these phenomena may be indicators as ancient earthquakes.

Key words: Instability osillation, Faulting trace, Abnormal array of subfaults

摘要： 对三轴实验中岩石突发式破坏和粘滑失稳的瞬时动态过程的研究表明,应力下降和位移增加都不是单一的,而是一种含有多种频率成分的振荡过程。用扫描电镜对错动面的观察表明,这种振荡导致双向或多向错动形迹的发育。结合天然断层面上常见的双向或多向错动的擦痕、阶步等形迹,以及断层带的异常构造,如反错列等,提出一次断层活动中失稳振荡-地震可能是这些特征的形成原因之一。反之,它们也有可能成为地震的一种标志。

关键词: 失稳振荡, 断层面形迹, 异常构造