【摘要】 玉门—北大河断裂是酒西盆地南侧的一条重要的活动断裂,断裂西起青草湾,向东经老玉门市、青头山、大红泉,止于北大河以东骨头泉一带,长约80 km,走向北西西,倾向南,倾角20°～60°。玉门—北大河断裂为一条全新世活动的逆冲断裂,断裂东段保留了地震破裂带遗迹,通过野外断错地貌调查和探槽开挖,揭示该破裂带形成于距今1.7±0.3 ka,此前断裂在4.1±0.3～5.4±0.3 ka及8.4±1.0 ka还有过2次古地震事件,利用经验公式和已有震例估算,每次地震震级约为M7。更多还原

【Abstract】 Yumen—Beidahe fault is an important active fault at the south margin of Jiuxi Basin. The fault starts from qingcaowan at west, passes through Yumen, Qingtou Shan, Dahongquan, and ends at the east of Gutouquan. The fault is about 80 km long, strikes NWW, inclines south and dips 20°～60°. Yumen—Beidahe fault is an active thrust fault in Holocene. Earthquake surface ruptures are still preserved at the eastern segment of the fault. Based on the filed fault geomorphological investigation and trench excavation, it is revealed that the rupture zone was formed 1.7±0.3 ka ago. there had been another two paleoearthquakes occurring in(4.1±0.3)～(5.4±0.3) ka and 8.4±1.0 ka, and the magnitudes of the two paleoearthquakes were estimated to be about 7.0 by empirical formulas and existing earthquake cases.更多还原