Abstract: 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.

Key words: Active block, Recent motion, Earthquake, Southern region of Sichuan-Yunnan Province

摘要： 根据近几年取得的新资料和当今有关活动地块的研究,提出划分川滇南部活动地块的思路、依据和具体方法,作者认为具有一定规模且其活动性延续至今的第四纪活动断裂是划分活动地块必需的首要边界条件。指出新生的腾冲-景洪北北西带和大理-楚雄北西西带在活动地块划分中的重要作用。根据断块边界断裂活动性质、运动方式和GPS资料等,分析讨论了各活动地块现今活动方式得出:≥7级以上地震主要集中在Ⅰ级活动地块边界;6～7级地震主要集中发生在Ⅱ级活动地块边界上;Ⅲ级活动地块是强震发生的主要位置所在。

关键词: 活动地块, 第四纪活动断裂, 地震破裂带, 川滇