Figure 4

Seafloor traces of the mega-splay fault, horizontal maximum stress and fracture orientations, and geometry of fault planes. (a) Seafloor traces of the mega-splay fault at the outer ridge off Kumano. Red lines represent the landward-dipping splay faults and trough axis, and blue lines represent the WBSF. The outer ridge is developed between splay fault and WBSF. The locations of cold seeps are denoted by yellow stars (Ashi et al. 2002; Ashi et al. 2003). (b) Horizontal maximum stress orientation estimated from borehole breakout data (e.g., Lin et al. 2010) and fracture orientation estimated from OBS data (Tsuji et al. 2011a) and walk-around VSP data (Tsuji et al. 2011b). The horizontal principal stress changes at the well-developed fracture band (red-colored area). (c) Geometry of the fault planes of the dominant shallow branched mega-splay fault (seaward of WBSF) extracted from several 2D seismic profiles (ODKM-03).