Some fundamental geomorphologic elements are distinguished in the forearc area. They are the volcanic chain, the basement high, the subduction complex and the trench. A sedimentary basin may occur behind or at the front of the basement high. These geomorphologic features are variable both by the mode of development and their location. The morphology and structure of the NE Japan margin reflect the cumulative effects of subduction since late Oligocence. The Upper Cretaceous basement is overlain by a few kilometers thick Late Cenozoic sediments on the Japan Trench forearc (Tohoku forearc). Structural features in the forearc such as the trend of the basin, faults, trench axis and the horst and grabens of the outer trench slope reflect a block structure whose individual element are of limited width. Local horizontal tensional force is suggested by surficial features of the forearc. The subduction complex is primarily governed by thrusts which cut the underthrusted oceanic basement beneath the complex, which suggests that there may be no way to consume the subduction complex to deeper parts of the subduction zone under the continental plate.