Article Volume 11 21 May 2010 Q0AD02, doi:10.1029/2009GC002668 ISSN: 1525‐2027 Click Here for Full Article Possible strain partitioning structure between the Kumano fore‐arc basin and the slope of the Nankai Trough accretionary prism Kylara M. Martin, Sean P. S. Gulick, and Nathan L. B. Bangs Institute for Geophysics, University of Texas at Austin, J. J. Pickle Research Campus, Building 196, 10100 Burnet Road (R2200), Austin, Texas 78758‐4445, USA (
[email protected]) Gregory F. Moore Department of Geology and Geophysics, University of Hawai’iatMānoa, Honolulu, Hawaii 96822, USA Juichiro Ashi and Jin‐Oh Park Ocean Research Institute, University of Tokyo, 1‐15‐1 Minamidai, Nakano‐ku, Tokyo 164‐893, Japan Shin'ichi Kuramoto and Asahiko Taira Center for Deep Earth Exploration, Japan Agency for Marine Earth Science and Technology, 3173‐25 Showamachi, Kanazawa‐ku, Yokohama 236‐0001, Japan [1] A 12 km wide, 56 km long, three‐dimensional (3‐D) seismic volume acquired over the Nankai Trough offshore the Kii Peninsula, Japan, images the accretionary prism, fore‐arc basin, and subducting Philippine Sea Plate. We have analyzed an unusual, trench‐parallel depression (a “notch”) along the seaward edge of the fore‐arc Kumano Basin, just landward of the megasplay fault system. This bathymetric feature varies along strike, from a single, steep‐walled, ∼3.5 km wide notch in the northeast to a broader, ∼5 km wide zone with several shallower linear depressions in the southwest. Below the notch we found both vertical faults and faults which dip toward the central axis of the depression.