Tectonic landforms and quaternary tectonics in Japan

Abstract

The study of tectonic landforms is one of the main themes of geomophological research in Japan, characterized as a tectonically active area along the subducting oceanic plates. The recent trends in the studies of tectonic landforms which include an arrangement or distribution of major ranges and plains, vertical displacement of low-relief erosion surfaces and of marine terraces, and various kinds of deformed features due to active faulting or folding, are introduced here with special reference to the Quaternary geomorphic development. A regionality of each tectonic landform is also summarized. Further, some fundamental concept on the Quaternary tectonics, for instance, an accumulative character of each type of deformation and sequence of rate of tectonic movement, reconstruction of former stress field as well as a relation between the Quaternary tectonic movement and seismic deformation in present and historic time are discussed on the basis of analysis of the tectonic landforms. The Quaternary tectonics of the Japanese Islands are essentially characterized by the compressional stress, originated from the subduction of oceanic plates, and regionality can be interpreted as the result of the different response of each tectonic region to island arc tectonics.

Natural regions of Japan

“…A subdivision of coastal geomorphology may therefore be suitable to show the local differences of uplift and subsidence, eventhough it is said that the velocity of tectonic movement during the Quaternary period does not show so great difference in Japan. According to the Research Group for Quarternary Tectonic Map (1969Map ( , 1973, the amounts of uplift and subsidence are distributed as shown in Fig 3 of Ota's paper in this issue (Ota, 1980). If we compare this figure with Fig 1 of the present paper, it is clearly seen that the amount of uplift is great in the regions of mountain ranges and, on the contrary, the amount of subsidence is great in the regions of basins or bays.…”