Abstract: Based on the geomorphic features of active fault, fault-related deposits and physical property of fault plane materials produced during the earthquake, the paleo-seismicity along the Heihekou fault since late Quaternary has been discussed in this paper. The ages of paleoearthquakes have been determined by using such relative dating techniques ascalcic soil development and geomorphic scarp evolution, with radiometric age control. The results have revealed that four events occurring along Heihekou fault since Quaternary. The first event occurred 25000 yrs. ago, and the others 13000, 10500 and 8500 yrs. ago, respectively. It is clear that the reccurrence intervals were different. This paper provides an emperical relation for the relative dating of paleoearthquakes in arid and semi-arid areas.

Key words: The Hexi Corridor, Active fault, Paleoearthquake

摘要： 本文从活断层地貌,断层作用的相关沉积特征,断层面物质受地震作用以后的物理变化等方面讨论了黑河口断层晚第四纪以来发生的古地震期次。并用钙土壤、地貌陡坎演化等相对年代方法,结合一些实验室样品年代,确定古地震发生的年代。结果表明:黑河口断层晚第四纪以来发生过四次古地震事件,一次发生在距今约25000年,另三次发生在距今13000、10500和8500年左右,为不均等间隔。本文还为干旱、半干旱区相对年代方法提供了区域“经验”关系。

关键词: 河西走廊, 活断层, 古地震