摘要
在青藏高原东北隅发育一系列向北东凸出的弧形断裂带,其中最主要的三条断裂带从北到南分别为牛首山-罗山断裂带、香山-天景山断裂带和天祝-海原断裂带。香山-天景山断裂带从上世新以来一直有过活动,并在1709年发生了中卫南71/2级地震。近期,宁夏地震局在孟家湾村南开挖了一个探槽,揭露出石炭纪的煤系地层逆冲于晚更新世风成沙之上,根据风成沙光释光测年结果表明,此探槽显示的断裂活动时代在距今约26.14±1.08 ka,极有可能为22.09±0.4 ka与26.14±1.08 ka之间。
There are a series of northeast forward are faults in the northeast corner of the Tibetan plateau. From south to north, there are three important faults, which is Niushoushan-Luoshan fault, Xiangshan-Tianjingshan fault and Tianzhu-Haiyuan fault. Earthquakes have been occurring on Xiangshan-Tianjingshan fault since Pliocene, and Zhongwei M71/2 earthquake occurred in 1709 on this fault. But most earthquakes occurred during Holocene. Recently, seismological bureau of Ningxia Hui autonomous region dug a trench in the south of Mengjiawan village. The trench reveals that Carboniferous coal measure strata thrusted onto late Pleistocene aeolian sand. According to the result of optical stimulated luminescence dating method, this trench reveals that the active time of the fault is about 26.14±1.08ka BP, especially between 22.09±0.4ka BP and 26.14± 1.08ka.
出处
《华南地震》
2013年第4期87-92,共6页
South China Journal of Seismology
基金
国家自然科学基金项目(40972118)
