The Longling-Lancang fault zone is a newly emerging fault zone, which is composed of multisecondary faults, distributed in the obligate or clustered types, and characterized by the zoning of active faults, earthquake faults and earthquakes. Its kinematic feature is dextral extensive and the formation epoch is early-middle Pleistocene. It is still active in the later period. The rupture in the future tends to cut across the tectonically-blocked segment, discontinuous segment of the fault and then through the whole fault zone. The formation of the nealy emerging fault zone has close relation with the uplift of the Qingzang Plateau. The composite action by the material fluid from the north to the south and the intrusion of Asamu block towards northeast makes the Dianmian block to rotate in a counter-clock wise direction and forms a new dextral shear, NNW-trending fault zone in the central area of the block.

Based on new data and studies on active blocks in recent years, we propose the principle, evidence and method for division of active blocks of the south region of Sichuan Yunnan Province. It is suggested that the Quaternary active faults which have major scales and have been active till present are the necessary and primary boundary conditions for block division. The newly formed Tengchong-Jinghong NNW zone and Dali-Chuxiong NWW zone have an important role in the block division. In the light of the nature of faults, motion modes, and GPS data the present-day active mode of each block is analyzed. It is concluded that earthquakes of M 7 or greater occur on the first class boundaries of active blocks, events of M6～M7 on the second class boundaries, and the active blocks of secondary class are the main locations of major earthquakes.