Rapid forearc basin uplift and megasplay fault development from 3D seismic images of Nankai Margin off Kii Peninsula, Japan

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doi: 10.1016/j.epsl.2010.09.034
Author(s): Gulick, Sean P. S.; Bangs, Nathan L. B.; Moore, Gregory F.; Ashi, Juichiro; Martin, Kylara M.; Sawyer, Dale S.; Tobin, Harold J.; Kuramoto, Shin'ichi; Taira, Asahiko
Author Affiliation(s): Primary:
University of Texas at Austin, Institute for Geophysics, Austin, TX, United States
Other:
University of Hawaii at Manoa, United States
University of Tokyo, Japan
Rice University, United States
University of Wisconsin-Madison, United States
Japan Agency for Marine-Earth Science and Technology, Japan
Volume Title: Earth and Planetary Science Letters
Source: Earth and Planetary Science Letters, 300(1-2), p.55-62. Publisher: Elsevier, Amsterdam, Netherlands. ISSN: 0012-821X CODEN: EPSLA2
Note: In English. 30 refs.; illus., incl. sects., geol. sketch map
Summary: Offshore Kii Peninsula, Japan, a large thrust within the overriding forearc, the megasplay fault, appears to move coseismically during great earthquakes. 3D seismic images of the Kumano forearc basin that overlies the megasplay, correlated with IODP drilling data, are a potential record of the history of large-scale motion along this structure. In the early Quaternary, uplift occurred in the southwest portion of the basin that may be a preliminary phase of motion along the megasplay. More extensive landward tilting of the outer basin sediments across the seismic volume occurred over ∼300 kyr in the middle to late Quaternary (1.3-1 Ma); this tilting event may represent the major period of motion along the megasplay that formed the modern fault geometry. Extensive normal faulting that cuts the forearc basin sediments clearly formed subsequent to the late Quaternary tilting and in many cases offset the modern seafloor; these faults may form either due to gravitational response to the uplift or as a by-product of sediment underthusting. These results suggest that the megasplay is a recently formed and transient structure and support the idea that out-of-sequence thrusts serving as the dominant structure for convergence-driven shortening in a subduction zone may be short-lived geologically but dominate a margin during these intervals. Abstract Copyright (2010) Elsevier, B.V.
Year of Publication: 2010
Research Program: IODP Integrated Ocean Drilling Program
Key Words: 16 Structural Geology; 20 Geophysics, Applied; Accretionary wedges; Asia; Basins; Cenozoic; Coseismic processes; Crustal shortening; Expedition 314; Expedition 315; Expedition 316; Extension; Far East; Faults; Fore-arc basins; Geometry; Geophysical methods; Geophysical surveys; Honshu; Imagery; Integrated Ocean Drilling Project; Japan; Kii Peninsula; Kumano Basin; Lower Quaternary; Megasplay faults; NanTroSEIZE; Nankai Trough; Normal faults; North Pacific; Northwest Pacific; Ocean floors; Offshore; Pacific Ocean; Plate tectonics; Quaternary; Sediments; Seismic methods; Subduction; Subduction zones; Surveys; Three-dimensional models; Thrust faults; Tilt; Transient phenomena; Uplifts; Velocity structure; West Pacific
Coordinates: N330000 N333000 E1364500 E1363000
Record ID: 2011034400
Copyright Information: GeoRef, Copyright 2017 American Geosciences Institute. Reference includes data from CAPCAS, Elsevier Scientific Publishers, Amsterdam, Netherlands