Evidence for a Tang-Song Dynasty great earthquake along the Longmen Shan Thrust Belt prior to the 2008 M w 7.9 Wenchuan earthquake, China
Evidence for a Tang-Song Dynasty great earthquake along the Longmen Shan Thrust Belt prior to the 2008 M w 7.9 Wenchuan earthquake, China
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DOI：
10.1007/s10950-010-9186-7
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发表时间：
2010-07-01
影响因子：
1.6
通讯作者：
Miyairi, Yosuke
中科院分区：
文献类型：
--
作者：
Lin, Aiming;Ren, Zhikun;Miyairi, Yosuke
2008年5月12日发生在中国龙门山地区的7.9级汶川地震，该地区位于青藏高原和四川盆地之间的过渡地带，在中国中西部造成了广泛的破坏。青藏高原东缘地势陡峭，地形起伏大，新生代经历了快速的隆升和剥蚀，并伴随着褶皱和逆冲，但在2008年汶川7.9级地震之前没有发生过大规模逆冲地震。野外和发掘调查表明，四川地区发生了一次大地震，导致中国龙门山逆冲带内一条> 200 km长的逆冲断层破裂，这也引发了2008年汶川7.9级地震。本次历史地震产生的平均同震滑动量估计为2 - 3 m，与2008年汶川地震产生的滑动量相当。古地震、考古学证据和放射性碳测年结果表明，四川地区的倒数第二次大地震发生在唐宋晚期，即公元800~1000年，暗示龙门山冲断带全新世晚期汶川级（M =类8）地震的重现期约为1,000-1,200年。这一发现与以前根据全球定位系统和地质数据的长期滑动率得出的龙门山冲断带内大地震复发间隔为2，000 - 10，000年的估计相反，因此有必要对青藏高原东缘人口稠密地区的现有地震灾害模型进行重大修改。
The magnitude (M (w)) 7.9 Wenchuan earthquake occurred on 12 May 2008 in the Longmen Shan region of China, the transition zone between the Tibetan Plateau and the Sichuan Basin, resulting in widespread damage throughout central and western China. The steep, high-relief eastern margin of the Tibetan Plateau has undergone rapid Cenozoic uplift and denudation accompanied by folding and thrusting, yet no large thrust earthquakes are known prior to the 2008 M (w) 7.9 Wenchuan earthquake. Field and excavation investigations reveal that a great historical earthquake occurred in the Sichuan region that ruptured a > 200-km-long thrust fault within the Longmen Shan Thrust Belt, China, which also triggered the 2008 M (w) 7.9 Wenchuan earthquake. The average co-seismic slip amount produced by this historical earthquake is estimated to be 2-3 m, comparable with that caused by the 2008 Wenchuan earthquake. Paleoseismic and archaeological evidence and radiocarbon dating results show that the penultimate great earthquake occurred in the Sichuan region during the late Tang-Song Dynasty, between AD 800 and 1000, suggesting a recurrence interval of similar to 1,000-1,200 years for Wenchuan-magnitude (M = similar to 8) earthquakes in the late Holocene within the Longmen Shan Thrust Belt. This finding is in contrast with previous estimates of 2,000-10,000 years for the recurrence interval of large earthquakes within the Longmen Shan Thrust Belt, as obtained from long-term slip rates based on the Global Positioning System and geological data, thereby necessitating substantial modifications to existing seismic-hazard models for the densely populated region at the eastern marginal zone of the Tibetan Plateau.