Abstract: By analyzing rock failure experiment with patches of the opposite slip direction of the parallel faults through the spatial and temporal evolution images of strain field, rock failure process and mode are studied. Moreover, by analyzing the interaction among patches and two faults'failure, the mechanism that enhances or delays the occurrence of an earthquake in the above model is deeply studied. Results suggest that the interaction mode is to advance the time of occurrence of seismicity. At last, the paper simulates the experimental results by the finite simulation method, showing that experimental results are consistent with those of simulative ones, and also indicating that experimental result is of reproducibility.

Key words: Patch, Opposition of fault slip direction, Instability and failure, Strain field