Abstract: By inversion of fault slip data, it is suggested that stress field of the region from the Haiyuan Liupanshan fault zone to the Yingchuan fault-depression has two major stages. Before early Pleistocene the maximum principal compression stress direction was NE-SW, the stress regime was reverse type, witch resulted in dominating reverse faults. After early to middle Pleistocene the tectonic stress field had a readjustment, the maximum principal compression stress direction was changed from NE-SW to NEE-SWW, the stress regime from reverse type to strike-slip type too, and the former reverse faults became strike-slip faulting, which continues much the same today. The recent tectonic stress field of the studied area can be divided into strike-slip region of Haiyuan fault zone, mixed region of reverse and strike-slip of Liupanshan and extension region of Yinchuan fault-depression.

Key words: Haiyuan fault zone, Tectonic stress field, Quaternary

摘要： 利用断层滑动资料反演构造应力张量从而确定出海原、六盘山断裂带至银川断陷的第四纪两期构造应力场:早更新世末期以前,为北东-南西挤压型构造应力场,由此造成该地区断裂活动主要以逆断为主;早更新世末期至中更新世以后,构造应力场发生了调整,主压应力方向由早期的北东-南西改变为北东东-南西西,应力结构由挤压型转变为走滑型,并导致断裂活动由早期的逆断为主变为走滑为主,这种应力场格局一直持续至今。研究区现代构造应力场可划分为:海原断裂带走滑应力区、六盘山逆断-走滑混合应力区和银川断陷拉张应力区。

关键词: 海原断裂带, 银川断陷, 构造应力场, 第四纪