Along-strike variation of the frontal zone structural geometry of the Central Longmen Shan thrust belt revealed by seismic reflection profiles
Along-strike variation of the frontal zone structural geometry of the Central Longmen Shan thrust belt revealed by seismic reflection profiles
复制标题
地震反射剖面揭示的龙门山冲断带中部锋带结构几何沿走向变化
DOI：
10.1016/j.tecto.2012.09.018
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发表时间：
2012-12
期刊：
影响因子：
2.9
通讯作者：
Chen, Yuegau
中科院分区：
文献类型：
--
作者：
Suppe, John;Ma, Yongsheng;Liu, Bo;Chen, Yuegau
2008年汶川8.0级地震使龙门山造山带北川-映秀冲断带和彭关冲断带沿着两条大断裂发生破裂。研究了龙门山中段山前彭官冲断带的构造几何学特征。为了识别彭官冲断带的同震断层，本文结合地质图、钻井资料、DEM数据和地表断裂构造，对多条二维/三维地震反射剖面进行了解释。结果表明，彭官冲断带发育三条主干断裂和多条分支断裂。主要断层在浅地层中形成叠瓦状和伴生的小复式。彭官断裂浅部倾向陡，深部倾向缓。北川-映秀断裂和彭官断裂均发育在龙门山中段的浅部拆离体上。第三条（③号）彭官断裂与同震地表破裂相吻合。这是一个预先存在的断层，并在汶川地震期间重新激活。三维几何形态表明，③号断层具有不均匀性，控制了同震破裂的滑动。根据区域地质特征、三维断层几何特征和地表破裂特征，将龙门山中段前缘带划分为白鹿段和汉旺段。研究表明，彭关断裂新生代以来一直活动。龙门山中段冲断带前缘带具有发震潜力。
The 2008 Ms 8.0 Wenchuan earthquake of China ruptured two large faults along the Beichuan-Yingxiu thrust belt and the Pengguan thrust belt at the Longmen Shan Orogenic belt, eastern margin of the Tibetan Plateau. Our study focused on the structural geometry at the Pengguan thrust belt located at the frontal zone of the Central Longmen Shan. In this paper, in order to identify the co-seismic fault at the Pengguan thrust belt many 2-D/3-D seismic reflection profiles have been interpreted by integrating with the geological maps, drilling data, DEM data and the surface ruptures. The results show that there were three major faults and other branch faults at the Pengguan thrust belt. The major faults have formed as imbricates and associated minor duplexes within the shallow strata. The Pengguan fault has a steep dip at the shallow surface and a gentle dip at depth. Both the Beichuan-Yingxiu fault and the Pengguan fault were developed on the shallow detachment in the central segment of Longmen Shan. The third (No. ③) Pengguan fault is coincident with the co-seismic surface ruptures. It was a pre-existing fault and re-activated during the Wenchuan earthquake. Three-dimensional geometries show that the No. ③ fault is heterogeneous and it has controlled the slip of co-seismic ruptures. Based on the regional geology, the 3-D fault geometry and the surface ruptures, the frontal zone of the Central Longmen Shan has been divided into the Bailu segment and the Hanwang segment. Our studies suggest that the Pengguan fault has been active since the Cenozoic. The frontal zone of the Central Longmen Shan thrust belt has potential for future earthquakes.
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影响因子：
3.1
作者：
C. Baudon;J. Cartwright
通讯作者：
C. Baudon;J. Cartwright
影响因子：
5.8
作者：
R. Larson
通讯作者：
R. Larson
影响因子：
2.9
作者：
A. Yin
通讯作者：
A. Yin
影响因子：
4.2
作者：
R. Allmendinger
通讯作者：
R. Allmendinger
影响因子：
2.9
作者：
J. Suppe
通讯作者：
J. Suppe