摘要：Seismic reflection profiles reveal steeply landward-dipping splay faults in segment B (the 1946 Nankai earthquake rupture, M 8.3) as well as segment C (the 1944 Tonankai earthquake rupture, M 8.1) of the Nankai subduction zone.The splay faults, branching upward from the plate-boundary interface, almost reach the seafloor, producing seafloor fault scarps.The swath-bathymetry map exhibits a ∼200-km-long, remarkable seafloor lineament with which the seafloor fault scarps align in the segments B and C.The seafloor lineament, which we believe is produced by repeating slips on the splay faults, is almost laterally continuous across a stable boundary off Kii Peninsula inbetween the two segments.These seafloor and subsurface features could be due to multiple, simultaneous coseismic slips across the B–C boundary, when subduction thrust earthquakes accompany the co-seismic slips on the splay fault.The splay faults are associated with (1) fluid expulsion, (2) dynamic deformation, and (3) tsunami generation. Key words Nankai subduction zone splay fault segment boundary simultaneous slip.
关键词：Nankai ;subduction zone ;splay fault ;segment boundary ;simultaneous slip
