Abstract
The Japanese arc system is one of the typical island arc system in the globe. The framework of plate tectonics, however, is still disputable. The author tries to elucidate the tectonic framework of this island arc system from the view point of slip rate of active faults and subsidence of tectonic basins. In past few decades, we accumulate knowledge on the active tectonics. Especially slip rate of active faults during the late Quaternary have been revealed by intensive works. Subsurface geology has also been investigated by many institutes. The author integrates the mean slip rate of active faults and distribution of subsidence-dominant Quaternary basins in the Japanese arc system. The results show the following facts. 1) Horizontal shortening rate around central Hokkaido is much lesser than its around the Fossa Magna region. 2) Major horizontal displacement occurs along the Japan Sea coast of the Northeastern Honshu, in the inner zone from the mid Honshu to Kinki district and along the Median Tectonic Line in the Shikoku and Kyushu. 3) All of the subsidence dominant fault-related basins occur along the highly active faults. These facts suggest the following allocation of the plates. 1) Distribution of highly active faults generally accords with high strain rate area observed by GNSS except for the outer zone where coupled with subsiding Oceanic plates. 2) Major collision boundary between the North America (Okhotsk) plate and Eurasia (Amur and South China) plate occurs along the Fossa Magna region. But collision between the Northeastern Japan arc and Kuril arc have still continued. 3) The eastern and southeastern boundary of Amur plate locates along the eastern margin of the Japan Sea, Hokuriku district, Kinki district and the Median Tectonic Line. This plate boundary agrees with Niigata-Kobe Tectonic Line and Active fold belt of Eastern Margin of the Japan Sea. Timing of tectonic evolution along this boundary is concurrent with along the Baikal rift zone.
