先新第三系中に発達する鉛直に近い回転軸を持つ様々な形態の摺曲（屈曲） : 中期中新世における西南日本の時計回り回転と関連して

Various folds (bends) with subvertical/vertical axes are widely developed in the pre-Neogene terranes of Southwest Japan. They are variable in shape, conical folds, accordion folds, megakink bands and so on, and some of them are associated with strike-slip faults. Their size ranges from several meters to 10km or more in half-wavelength. Their deformation style indicate that they were produced under a brittle condition in a shallow level of the crust. They are superimposed on the pre-existing structures, and are regarded to have been formed mostly during the Middle Miocene contemporaneously at the time of the clockwise-rotation of Southwest Japan. The presence of them, thus, suggests that the upper crust of island arc is easily deformable around subvertical/vertical rotation axes to form various folds (bends) and locally strike-slip faults during its rotation.