Abstract
The deformations of fluvial terraces along the lower course of the Shinano River and its tributaries are well. known examples of active folds in Japan. The Shinano River flows almost northward approximately parallel to the main synclinal structure of the Plio-Pleistocene Uonuma Group, and pours into the Sea of Japan. Therefore, active folds succeeding its structure appear as the deformation of cross sections of terrace plains. The pattern of deformation due to active folding is demonstrated in the terrace distribution map and cross sections. Details of several examples of folded terraces are explained based on the descriptions of newly found good outcrops which confirm the deformation of terrace surfaces concordant with the foldings of terrace deposits.
