PROGRESSIVE COALESCENCE MODEL FOR BRITTLE FAULT FORMATION AND ITS MECHANISM

In shallow crust, faults often consist of a series of secondary fractures. Based on experimental micro-features in rock mechanics and macro-structures in field, the progressive coalescence model, in which a brittle fault evolved from micro-crack, stylolitic fracture, large fault to super-large fault, is founded, and its forming mechanism is discussed by variation of stress field. At last the undulation,branches of faults and the phenomenon that the angle between fractures and the principal stress axis decreases gradually are explained by the G. C. Sih model.