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叙述长江三峡地区四条地震测深剖面沉积层与基底层速度细结构的研究结果．测区西部的鄂西丘陵地区沉积盖层速度较大，总厚度为０～３ｋｍ，但在秭归盆地南侧与沮水河谷沉积层厚度加大，分别为５．０与４．０ｋｍ．测区东部的江汉平原区沉积盖层巨厚，达５～８ｋｍ．速度明显偏小．基底面速度在整区达６ｋｍ／ｓ以上．在沉积层内部还可细分一层面，在江汉平原区深度达３～４ｋｍ，而在其它地区接近地表．剖面多处为断裂所切割，断裂所经之处不仅速度等值线变化剧烈，且速度值也明显偏低．基底层以速度高并梯度小著称，层内存在三处高速异常区，分别位于黄陵背斜的西、南和东侧．它们是地壳深处玄武岩类高速物质上涌产物，估计这过程发生于黄陵背斜形成之前．由于其活动，造就或影响了基底面剧烈深度变化，以及相应断裂的发育与活动
The results of the study on fine structure of sediment and basement velocities of four seismic profiles in the Three Gorges area of the Yangtze River are described. The sedimentary cover in the western Hubei hilly area in the western part of the survey area is relatively large with a total thickness of 0 ~ 3 km. However, the thickness of the sedimentary layer in the south of the Zigui Basin and the Ju River valley is 5.0 and 4.0 km, respectively. The sedimentary cover of the Jianghan Plain in the east of the survey area is very thick, reaching 5 ~ 8km. The speed is obviously small. Basal surface velocity in the entire area up to 6km / s or more. Within the sediment layer can also be subdivided into a layer of surface depth in Jianghan up to 3 ~ 4km, while in other areas close to the surface. Many sections of the section are cut by the fault, where not only the velocity contour change drastically but also the speed value obviously lower. The basal layer is famous for its high velocity and small gradient. There are three high-velocity anomalies in the layer, which are located on the west, south and east of the Huangling anticline. They are high-velocity basaltic upwelling products of deep basalts. It is estimated that this process occurred before the formation of the Huangling anticline. Due to its activity, the drastic depth changes of the basal plane and the development and activities of the corresponding faults are created or influenced