Geometrical textures of faults, evolution of physical field and instability characteristics

The spatial and temproal evolution of strain, fault displacement and acoustic emissions during deformation of fault systems with different geometrical textures are studied experimentally under biaxial compresison, and the characteristics of typical instability events are analysed. The results show that fault systems with different geometrical textures have different evolutional images of physical field during deformation. Based on the characteristics of physical field and the deformation mechanism, various types of instability — two types of stick-slip, fracturing type and mixed type instability can be recognized. Different types of instability differ clearly in their precursors, and the instability type is closely related with the geometrical texture and the deformation stage of the fault system. Therefore, it is very significant for earthquake prediction and precursor analysis to investigate the geometrical textures of natural active faults.