An introduction to the Cenozoic tectonics of the Japan arc

Abstract

Although not well constrained, spreading in the Japan Sea probably began at~20 Ma; deformation of the Japan arc from 18-20 Ma to 15 Ma was a response to its overriding of the Pacific plate. The collision of the Philippine Sea plate against SW Japan (1) stopped spreading both in the Japan Sea and Shikoku basin at 15 Ma, (2) formed a triple trench junction off Central Japan and (3) divides the arc into the SW and NE Japan arcs. The SW Japan arc has been subjected to compression deformation since this event, whereas a change from compressional to extensional deformation commenced in the NE Japan arc during the Pliocene.