Abstract: Many investigations have been made on a series of strong earthquakes that occurred in Mabian-Yongshan-Leipo, Daguan area successively. Basing on the characteristics of folds and faults and distribution of stress, we suggest that there exists a relative variation process, being from strong to weak, from west to east. It is inferred that the source of stress may be derived from a lateral pushing force and the resulting seismic zone forms a part of Mabian-Zhaotong-Qujing fault zone, being an eastern boundary of longitudinal tectonic zone in West Sichuan, and also being an earthquake-controlling basement fault zone along the boundary between geotectonic elements, Qinghai-Xizang plateau and Sichaun basin.

Key words: Mabian-Yongshan seismic zone, Imbricate structure, Overlying strata decollement, Himalayan tectonic domain

摘要： 根据该地褶皱形态、断裂特征、应力场分布等资料研究,指出马边～永善及其两侧的构造形迹自西而东有一个相应强～弱变化过程。推测其力源主要来自西部喜马拉雅构造域的侧向推挤,所形成的马边-永善地震带是处于马边-昭通-曲靖断裂构造带的一部分,从而成为川西经向构造带的东部边界,也是青藏高原东南边缘与四川盆地西南边缘的浅部界线。

关键词: 马边-永善地震带, 推覆构造, 盖层滑脱, 喜马拉雅构造域