Faulting on the Anninghe fault zone, Southwest China in Late Quaternary and its movement model

Abstract

The Anninghe fault is one of the significant earthquake-generating fault zones in the Southwest China. Local historical record shows that a M≥7 strong earthquake occurred in the year of 1536. On the basis of the detailed air-photographic interpretation and field investigation, we have acquired the following knowledge: ➀ The average sinistral strike-slip rate since the Late Pleistocene is about 3∼7 mm/a; ➁ There is important reverse faulting along the fault zone besides the main left-lateral strike-slip motion, and the shortening rate across the Anninghe fault zone due to the reverse faulting is about 1.7∼4.0 mm/a. If the Xianshuihe fault zone is simply partitioned into the Anninghe and Daliangshan faults, we can also get a slip rate of 3∼7 mm/a along the Daliangshan fault zone, which is the same as that on the Anninghe fault zone. Moreover, on the basis of our field investigation and the latest knowledge concerning the active tectonics of Tibetan crust, we create a dynamic model for the Anninghe fault zone.