Deformation feature of active fault and recurrence period estimation of large earthquake

Active faults are refer to all kinds of faults that have been active since 0.1~0.12 Ma of the Late Pleistocene, and are active at present and will be active in future. Active faults are causative structures of various earthquakes and are control of great earthquakes. According to the deformation features, model of causative structures are also different for different active faults, then researches related are important for studying the causative condition of great earthquake, determining potential focal region or seismic risk region, and evaluating causative structure and its location. In this paper, combining the researches on active faults in the Qinghai-Tibetan Plateau in recent ten years at home and abroad we have summarized, general deformation characteristics of active fault and estimation methods of large earthquake recurrence period. The results show that recurrence period is 250-350 years for Hoh Sai Hu earthquake (Ms 8.1) in 2001 on the East Kunlun fault, 370-500 years for Mw 7.4 earthquake on the Kangxiwar segment of the Altyn Tagh fault, and 3000-6000 years for Wenchuan earthquake (Ms 8.0) in 2008 in the Longmenshan area, the east margin of Qinghai-Tibet Plateau. The data indicate that recurrence period of large earthquake on strike-slip fault is possibly much less than that on thrust fault, which is a new subject should be highly emphasized and thoroughly studied.