德干断裂系的特征、活动性与地震危险性评价

The Feature,Activity and Seismic Risk Evaluation of Deccan Faults

乌东德水电站场址附近走向NNE的德干断裂系主要由裸佐断裂、马店断裂、鹿鹤断裂等组成,全长约120km。该断裂系向北收敛,向南呈＂帚状＂撒开成多条分支近平行排列,展布宽约6km。断层构造岩均为脆性变形所产生的碎裂岩系,断裂带内各种次级组构表明,该断裂系在新构造时期存在多次构造活动,且活动强度由强逐渐变弱。断裂最新活动年代在中更新世,运动方式为粘滑兼有稳滑。地震危险性分析认为,倮佐断裂的最大地震震级为6.0级,马店断裂、鹿鹤断裂等在5～5.5级之间。

Deccan faults striking NNE with a total length of about 120 kin, consisting of Luozuo fault, Madian fault, Luhe fault, etc, are located near the darn site of Wudongde hydropower. The fault weakens to the north and forms into multiple branch faults in a nearly parallel 6kin 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.