Abstract: The deep-seated and major fault with strong activity may cause discontinuty of deep crustal boundary and distribution of anomalous gravity fields, and represent various phenomena by the upper crustal movement. We have calculated crustal thickness by use of gravity data, and then researched further the linear fracture system on the ground surface and the display of present crustal movement in Three-Gorge region, western Hubei province. The authors have come to following conclusion: the gravity anomaly gradient belt trending NNE in Three-Gorge region is not the result of recent deep-seated faulting; the tectonic environment should be not for occurring earthquake in the deep crust.

Key words: Western Hubei province, Three-Gorge, Graivty field, Seismotectonics

摘要： 深大断裂的强烈活动不仅能造成深部地壳界面不连续(变异)和重力场的异常分布,同时在上部地壳有相应的显示。基于这一思路,本文利用重力资料计算反演了鄂西三峡地区地壳厚度分布、重力均衡状态,进而着重研究了地表线性断(破)裂系统和现代地壳运动特征(包括地震活动)。由此得出结论:三峡东部NNE向延伸的重力异常梯级带不是现代强烈活动的深部断裂(块)作用结果,即其深部似不存在孕育和发生强震的构造条件。

关键词: 鄂西三峡, 重力场, 地震构造