"The late-Cenozoic deformations in this fault (''that caused the 2008 Wenchuan earthquake'') are concentrated in the Guanxian-Jiangyou Jiangyou () is a Chinese county-level city located in Mianyang, Sichuan. The city proper is subdivided into four urban districts and has jurisdiction over 21 towns, and 19 rural townships. It is the hometown of Li Bai, a leading Tang Dynasty poe ...fracture (hill-front fracture), Yingxiu- Beichuan fracture (mid-fracture),Wenchuan Wenchuan County is a county in Ngawa Tibetan and Qiang Autonomous Prefecture, Sichuan, People's Republic of China. The county has an area of , and a population of 100,771 as of 2010. Wolong National Nature Reserve is a protected area located in ...- Mao County fracture (hill-back fracture), and their related folds. The recent Ms 8.0 earthquake occurred on the Yingxiu-Beichuan fracture, as a result of Longmenshan thrust pushing southeastward combined with clockwise shears. Since Holocene (10,000), Yingxiu-Beichuan fracture has had evident activities. Its long-term geological slip rate is slower than 1 mm per year. GPS observations confirm the current structural deformation of the Longmenshan formation to be characterized by thrust and right-handed shears, but with a low deformation rate. Therefore, Longmenshan formation and its internal fractures constitute a special type that has low earthquake frequences but the potential to cause super strong earthquakes."
Morphology
The American Geophysical Union publication ''Tectonics'' describes the 5 km high escarpment thus:"In the Longmen Shan region, however, the topographic margin of theTibetan Plateau The Tibetan Plateau (, also known as the Qinghai–Tibet Plateau or the Qing–Zang Plateau () or as the Himalayan Plateau in India, is a vast elevated plateau located at the intersection of Central, South and East Asia covering most of the ...is one of the world's most remarkable continental escarpments. Elevations rise from circa 600 m in the southernSichuan Basin The Sichuan Basin (), formerly transliterated as the Szechwan Basin, sometimes called the Red Basin, is a lowland region in southwestern China. It is surrounded by mountains on all sides and is drained by the upper Yangtze River and its tribut ...to peaks exceeding 6500 m over a horizontal distance of less than 50 km. Regional topographic gradients typically exceed 10% along this mountain front and rival any other margin of the plateau."
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