An Active Folding in the Shonai Plain

Abstract

An active folding in the vicinity of Amarume city, Yamagata pref. is indicated by the followings: -
1) The two-dimensional pattern of the river bed of the Mogami and the Fujishima.
2) Meandering of the former river bed of the Mogami.
3. The results of levelling showing the seismic changes before and after the Niigata earthquake in 1964.
4) The landform of the southern area of Shonai plain given by the 10 m and 15 m contour-lines.
5) The existence of the anticlinal structure of the Neogene series buried under the alluvium.