A FAHIMIFAR - Professor,AmirKabir University of Technology ,Tehran ,Iran

Stick-slip Phenomenon is believed to be one of the major approaches to the problem of understanding the earthquake mechanism.For this purpose,an extensive experimental investigation was conductedto explore stick-slip characteristics of six type of rocks containing a single joint and testing triaxially upto ۷۰ MPa Confining pressure . A critical review of the previous works reveals that most of the experimental investigations performed on the stick-slip phenomenon have not been conducted in Favourable testing conditions.For this reason ,different configurations of seat and platen in the cell - specimen system were used to clarify further the previ-ous works and investigate significant aspects of stick-slip with respect to the sliding characteristics of the rock used in this experiment . Two types of stick-slip are introduced which are expected to be appropiate mode-ls to interpret earthquake mechanism