Strike-slip motion of a mega-splay fault system in the Nankai oblique subduction zone

Takeshi Tsuji, Juichiro Ashi, Yasutaka Ikeda

    研究成果: Contribution to journalArticle査読

    34 被引用数 (Scopus)


    We evaluated the influence of the trench-parallel component of plate motion on the active fault system within the Nankai accretionary wedge from reflection seismic profiles, high-resolution seafloor bathymetry, and deep-towed sub-bottom profiles. Our study demonstrated that a large portion of the trench-parallel component of oblique plate subduction is released by strike-slip motion along a fault located just landward of and merging down-dip with a mega-splay fault. The shallow portion of the splay fault system, forming a flower structure, seems to accommodate dominant strike-slip motion, while most of the dip-slip motion could propagate to the trenchward décollement. Numerous fractures developed around the strike-slip fault release overpressured pore fluid trapped beneath the mega-splay fault. The well-developed fractures could be related to the change in stress orientation within the accretionary wedge. Therefore, the strike-slip fault located at the boundary between the inner and outer wedges is a key structure controlling the stress state (including pore pressure) within the accretionary prism. In addition, the strike-slip motion contributes to enhancing the continuous mega-splay fault system (outer ridge), which extends for approximately 200 km parallel to the Nankai Trough.

    ジャーナルearth, planets and space
    出版ステータス出版済み - 12 1 2014

    All Science Journal Classification (ASJC) codes

    • 地質学
    • 宇宙惑星科学


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