Chronological Studies of Mountain Uplift with the Use of Identification and Correlation of the Widespread Tephra Layers.

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1. Three types of the uplift history were distinguished from the mountains in the Japanese Islands through the information obtained from the chronological studies of Quaternary sediments in and around the mountain area.2. Two widespread tephra layers, that are useful for clarifying the uplift history of mountains in central Japan, were identified and correlated between central Japan and other Quaternary sedimentary basins.3. The Kannawa fault along the onshore plate boundary zone in central Japan has ceased its activity since 0.2-0.3 Ma. Recent activity is replaced by the young active faults.4. Four tephras in the plio-pleistocene sediments being consisted of the Nishi-kubiki Mountains, southwestem Niigata Prefecture, were identified and correlated with some pyroclastic flows in the Hida Mountains, central Japan. This information suggests that the Nishi-kubiki Mountains commenced their uplift at about 2.7 Ma.5. Tilting rate obtained from the terrace heights along the Kurobe river suggests that the Hida mountains had experienced more intense uplift in the middle Pleistocene than in the present.6. Tephra layers on the Kureha Hills in Toyama have possibility to be identified with the mid-Quaternary pyroclastic flows in the Hida Mountains.7. Detailed analysis of the deep drilling cores from the Nobi sedimentary basin revealed that the Nobi tilting movement started its activity at early Pleistocene and has accelerated sharply since the middle Pleistocene.8. Tephrochronological studies for the plio-pleistocene sediments in southwest Japan revealed that the Kyushu and Shikoku Mountains started their uplift movements at 2-3 Ma. These result from the increasing of E-W compression caused by the oblique subduction of PHS and eastward migration of the Amurian Plate.