第四紀の地殻変動  [in Japanese] Recent studies on the Quaternary tectonic movement of Japan  [in Japanese]

The Japanese Islands are tectonically very active during the Quaternary Period. The evidence is very cleary reflected in the results of geodetic, topographical and geological observation. The studies on those phenomena are being conducted with great enthusiasm and have been summarized several times since 1960's. The recent upheaval of mountains and peninsulas was clarified by geodetic, topographical and geological means. These occurrences are intimately related to the seismic activities. Most of the destructive earthquakes occur under the surrounding areas of these mountains, due to their flexural deformation. It was shown that the subsidence of plains is now in progress, and the basement of the plains is broken into blocks, and the hypocenters of destructive earthquakes are situated under those flexural parts in the Kanto Plain. Many active faults are found all over the islands, but divergent opinions are expressed on the movements of some faults. Several active folds were found in the inner zone of Northeast Honshu, and it was pointed out that the rate of folding was comparable to the inclining of river terraces in some areas. It was found that some folds were in action, but the movement was not always parallel to the form of folds, as the fold was formed step by step.