Characteristics of the active Xiaojiang fault zone in Yunnan, China: a slip boundary for the southeastward escaping Sichuan–Yunnan Block of the Tibetan Plateau

Abstract The Xiaojiang fault zone, within the Yunnan Province, China, is one of the most active fault zones of the southeastern edge of the Tibetan Plateau. This N–S trending 400 km long fault zone defines the southern part of the eastern boundary of the Sichuan–Yunnan Block, which is escaping southeastward from the Tibet Plateau and rotating around the Eastern Himalayan Syntaxis. The middle section of the fault zone splits into two branches. Each branch fault consists of several en echelon faults. Basins of various ages have developed on the step-overs between the secondary faults. The left-lateral strike–slip rate along the eastern branch is up to 9 mm/a, and that on the western branch is 7 mm/a. More than 10 M≥6 historic earthquakes have occurred along the fault zone. The largest was the 1833 Songming earthquake of M=8. Four earthquake rupture zones were discovered along the fault zone. 15 trenches have been excavated along every major segment of the fault zone and 4–5 paleoearthquakes have been distinguished along the Xiaojiang fault zone. The average strong earthquake recurrence interval is 2000–2500 years.

[1]  Robert E. Wallace,et al.  Earthquake Recurrence Intervals on the San Andreas Fault , 1970 .

[2]  R. Armijo,et al.  Quaternary extension in southern Tibet: Field observations and tectonic implications , 1986 .

[3]  R. Armijo,et al.  Late Cenozoic right‐lateral strike‐slip faulting in southern Tibet , 1989 .

[4]  Leigh H. Royden,et al.  Late Cenozoic Xianshuihe-Xiaojiang, Red River, and Dali Fault Systems of Southwestern Sichuan and Central Yunnan, China , 1998 .

[5]  P. Molnar,et al.  Cenozoic Tectonics of Asia: Effects of a Continental Collision: Features of recent continental tectonics in Asia can be interpreted as results of the India-Eurasia collision. , 1975, Science.

[6]  J. Dewey,et al.  The tectonic evolution of the Tibetan Plateau , 1988, Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences.

[7]  Robert W. King,et al.  Global Positioning System measurements from eastern Tibet and their implications for India/Eurasia intercontinental deformation , 2000 .

[8]  Peter Molnar,et al.  Active faulting and cenozoic tectonics of the Tien Shan, Mongolia, and Baykal Regions , 1979 .

[9]  Peter Molnar,et al.  Active faulting and tectonics in China , 1977 .

[10]  Paul Tapponnier,et al.  Updated interpretation of magnetic anomalies and seafloor spreading stages in the south China Sea: Implications for the Tertiary tectonics of Southeast Asia , 1993 .

[11]  P. R. Cobbold,et al.  Propagating extrusion tectonics in Asia: New insights from simple experiments with plasticine , 1982 .