?????????????½????????????????

?????????????????????????????????????????????????????????S??L????????????????????S??L/K???????????????????з??????????????о?????????????????????????????1??????????????????????????????????о??????????????????????????????????????????????????????????????????????????????????й??????????????????????????y?С???????1???????????

Implications of Active Structures in Head Area of the Three Gorges Reservoir by Characteristics of Stream Longitudinal Profiles

We examine the stream length-gradient SL index and gradient index SL/K for concavity studies, and analyze the tectonic activities in the head area of the Three Gorges reservoir based on DEM data and spatial analysis method. Consequent analysis reveals that the main factor causing the landform is tectonic uplifting. Tectonic fault exhibits a strong influence on river profile in the study area. However, the tectonic processes are distinct in different tributaries. The tectonic activities are very strong in the left bank and weak in the right bank. The differential lithology distribution is also anther aspect of the profile feature. In a general, the longitudinal profiles of the river tributaries are well controlled by neotectonic movement, tectonic faults and lithological difference.