The Feature, Activity and Seismic Risk Evaluation of Deccan Faults
1 Yangtze Institute of Geotechnique & Survey,Ministry of Water Resources,2689 Jiefang Road, Wuhan 430011,China
2 Key Laboratory of Geotechnic Mechanics and Engineering, The Ministry of Water Resources
Yangtz River Scientific Research Institute,1863 Jiefang Road,Wuhan 430010,China
3 Three Gorges Geotechnical Consultants Co.,Ltd, 7-3-401 Startup Square, East Lake Development Zone,Wuhan 430074,China
Abstract Deccan faults striking NNE with a total length of about 120 km, consisting of Luozuo fault, Madian fault, Luhe fault, etc, are located near the dam site of Wudongde hydropower. The fault weakens to the north and forms into multiple branch faults in a nearly parallel 6km wide broom-like arrangement to the south. The fault rocks are cataclasite as a result of brittle deformation. All kinds of secondary structures in the fault zone show that the fault has undergone many tectonic activities in the new tectonic period, and the activity intensity is weakening. The latest fault activity was in Middle Pleistocene, mainly by stick slip motion. The largest earthquake magnitude of the faults are M6.0 in the Luozuo fault and M5-5.5 in the Madian and Luhe faults, by the evaluation of seismic risk.
