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Fig. 1 ( a ) Bathymetric map of the Nankai accretionary prism (NAP) showing the major tectonic
elements in the region and the location of our dive survey. Inset map depicts the plate boundaries
and the Nankai Trough. The Philippine Sea Plate (PSP) moves to the NNW at 4-7 cm/year.
Sediments on the PSP are off-scraped and accreted to the edge of the Southwest Japan Arc to form
the NAP. Bathymetric contour interval is 500 m. ( b ) Locations of dive sites visited by the manned
submersible SHINKAI 6500 as part of dives 6K#892 and 6K#893. These surveys targeted the
hanging wall of the Tokai Thrust, which is one of the largest out-of-sequence thrust faults within
the NAP. The submersible surveyed the sidewalls of the Tenryu Submarine Canyon, which down-
cuts through ~1 km of the NAP strata. In the lower slope of the sidewall, down to ca. 300 m from
the bottom of the canyon, the strata are steeply dipping and characterized by foliated mudstone
and sandstone, whereas in the upper slope the strata are composed mainly of horizontal turbidites.
Bathymetric contour interval is 10 m. ( c ) Topographic profiles and schematic structural sections
along X-X¢ and Y-Y¢ in b, based on the results of our dive surveys and the seismic profiles by
Mazzotti et al. ( 2002 ) and Kuramoto et al. ( 1999 )
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