Central Japan triple junction: a three-dimensional compression model

Abstract

We present a new interpretation of the tectonics of the trench-trench-trench triple junction off central Japan, using more specifically data obtained during the French-Japanese Kaiko cruise in 1984. Data analysis and consideration on the three-dimensional geometry of the junction and its kinematics lead to the conclusion that the whole area undergoes large-scale compressional intraplate deformation. This is caused by the subduction of the Philippine Sea plate in the restricted space between the Pacific and Northern Honshu plates. We then apply the same analysis to the whole central Japan area, for which we consider the role of the interaction of the three plates at depth as a basis for tectonic reconstructions since the Miocene.