Fig. 2 Geology of the frontal thrust zone. ( a ) Track of Dive 6K#938 in the 1st ridge (map area
indicated in Fig. 1b ). Localities of photographs ( b - h ) and samples with porosity and uniaxial
compressional strength (UCS) data are shown. ( b ) Outcrop of fossilized cold seep zone. A fossil
of Vesicomyid bivalve ( inset ) was found buried in conglomerate. ( c ) An outcrop with orthogonal
joint sets. Field of view (FOV) ~ 3 m. ( d ) Bedding planes with cross laminae. FOV ~ 2 m.
( e ) Ripples and dark sand covering a hump extending southeast from the crest of the 1st ridge ( a ).
( f ) An outcrop of a conglomerate interbedded with sandstone layers and cemented by carbonate
minerals. FOV ~ 3 m. ( g ) Thrust fault recognized as oblique plane filled with a thin light film,
offsetting bedding planes. FOV ~ 3 m. ( h ) Normal faults offsetting bedding planes. Drags were
partly developed. FOV ~ 1 m