 The Xianshuihe fault system comprises several distinct segments, with an overall length of about 350 km.The main segments are the Ganzi (or Ganzi-Yushu), the Xianshuihe, the Anninghe-Zemuhe, and the Xiaojiang faults.Movements on this fault system have been responsible for many large historical earthquakes, with more than 20 events of magnitude greater than 6.5 since 1700.