Fig. 5

The schematic diagrams indicate structural evolution at the region around MCS line ODKM-B of the northern margin of the Kumano forearc basin from ~ 6 Ma. Ages from (a) to present (c) are on the basis of Fig. 5. Note that the sedimentation, unconformities, and deformation are related to each other and that structuring might be currently occurring. a The back-thrust started with the growth of accretionary prism. First slope sediments (Unit 3) were involved into the deformation. b After the first settlement of the anticlinal crest of the accretionary prism, slope sediments deposited and covered the accretionary prism. A part of the forward thrust (white dotted thrust) tilted unit 2–2. c The northern edge of the Kumano Basin was reactivated ~ 4.0 Ma and promoted the deformation of the accretionary prism, tilting of the older slope sediments, and developed the growth strata of the forearc basin deposits. The reactivation of back-thrust and the doming of the anticlinal crest took place