Abstract: The active tectonic pattern and recent stress state in the seismic region of NW Yunnan province are discussed on the basis of field observation and in-situ stress measurements.Data.show that this region is characterized by pull-apart structures which are formed by the movement of two right-lateral strike-slip faults,the Red River and the Zhongdian fractures,and that the crustal stress state in this region is different from those in the surrounding areas.The earthquake distribution in time and space is controlled by the tectonic pattern and relevant stress states.

摘要： 本文根据野外调查和原地应力测量资料,讨论了滇西北地震活动区的活动构造型式和现今应力状态。资料表明,本区是由红河和中甸两条右旋走滑断裂所形成的拉分构造,其应力状态也与外区不同。地震在空间上的分布和在时间上的活动规律受这一构造型式及其应力状态的控制。