关键词: 云南, 小江断裂带, 滑动速率, 地震, 重复周期

Abstract: In this paper, the average slip rates of the western branch of the Xiaojiang fault zone are estimated as 6.7 mm/yr, 7.0 mm/yr and 6.4 mm/yr during the Quaternary period, the late Pleistocene epoch and the Holocene epoch respectively according to the offsets of the geomorphic and geologic features and their ages. Furthermore, the recurrence intervals of strong earthquakes and the activity of the fault zone are discussed on the basis of the estimate of the slip rates and the research on both prehistorical and historical seismicity. The results indicate that the western branch of the Xiaojiang fault zone is characterized by repeated activity which leads to the periodical occurrences of strong earthquakes. The average recurrence interval at the same site of the fault is about 900 years and that on the whole fault zone is more than 330 years.

Key words: Yunnan, Xiaojiang fault zone. Slip rate. Earthquake, Recurrence interval