Abstract: Qilianshan active fault zone is situated in the northeastern border of Tibet Plateau.It con-sists of North Qilianshan fault and Haiyuan fault. It is mainly a compressive-sheared and sinis-tral-slipping fault zone,its slip rate at most up to 9mm/a。Many ancient earthquakes and histori-cal earthquakes occurred in the zone.On the basis of the active behavior of the fault zone,three sections and seventeen segments were divided.According to the relation of ancient earthquakes,slip rate and length of segrnents,a bivariate regreession model was set up. The evalution of risk was made. Finally,we can disfinguish between three risk segments of type A and four risk seg-ments of type B.

Key words: Active fault, Regression analysis, seismic risk evaluation

摘要： 祁连山强震构造带由祁连山北缘断裂和海原断裂组成。断裂带主要表现为压扭性左旋滑动,最大滑动速率达9mm/a.沿带有一系列的古地震事件,且有多次历史地震发生。海原8.6级地震就发生在该带上。根据该带的断裂活动习性,按照一定的原则和依据划分成3个一级断层段和17个二级断层段。建立了古地震、历史大震图像识别和地震重现间隔二元分析的数学模型。在此基础之上对该带作了地震危险性别定,划分出3个A类危险段和4个B类危险段。

关键词: 活断层, 回归分析, 地震危险性评估