新疆柴窝堡盆地南缘断层盐湖段晚第四纪活动及古地震研究

The Activity and Paleoearthquake Research of Yanhu Segment in Late Quaternary of Southern Chaiwopu basin,Xinjiang

柴窝堡盆地南缘断层是依连哈比尔尕山与柴窝堡盆地的分界断层，盐湖南断层为柴窝堡盆地南缘断层东段。晚第四纪至今，该断层发生过多次显著活动，山前冲沟及河流II、III级阶地上均可见其活动迹象，并在山前冲洪积扇前缘形成连续陡坎。晚更新世以来，断层平均垂直活动速率0.22~0.45 mm/a，缩短速率1.25~2.5 mm/a，全新世以来的垂直活动速率为0.125 mm/a。通过野外实地踏勘开挖探槽、形变测量及热释光（TL）年代测定，获得了该断层晚第四纪以来活动的定量数据。古地震研究表明，柴窝堡盆地南缘断层盐湖段全新世至今曾发生3次古地震事件，时间分别距今（12.73±1.08）^（9.37±0.0.8） ka，（9.37±0.8）^（7.07±0.6） ka及（7.07±0.6）^（4.85±0.41） ka，离逝时间达4.8 ka以上。

Chaiwopu basin south Fault,the verge Fault between Yilianhabierga mountain and this basin,is the south boundary oF this basin.Yanhu south Fault belongs to the east segment of the Qaiwopu basin south Fault.Since late quater-nary,several obvious activities occurred in the Fault and the new active traces of the Fault can be Found in theⅡ,Ⅲter-rance or along the Front mountain’s gully.In the alluvial-proluvial Fan oF the Front mountain,the Fault scarps spread continuously. Since late Pleistocene,the Fault’s average vertical active rate is 0.22~0.45 mm/a and its shortening rate is 1.25~2.5 mm/a.The vertical active rate in the Holocene is 0.125 mm/a.In this paper,we obtain the quantitative data of the Fault’s late Quaternary activity.The paleoseismic study displays that there are three paleoearthquakes in the Holo-cene in the Yanhu segment oF the Qaiwopu basin Fault. The three occurrences happen,（12.73 ± 1.08）^（9.37 ± 0.8） ka, （9.37±0.8）^（7.07±0.6） ka and （7.07±0.6）^（4.85±0.41） ka ago,respectively. The elapsed time is over 4.8 ka.