New 3D seismic reflection images from the NanTroSEIZE Kumano transect

Author(s): Moore, G. F.; Bangs, N. L.; Yoro, T.; Tanaka, H.
Author Affiliation(s): Primary:
Japan Agency for Marine-Earth Science and Technology, Center for Deep Earth Exploration, Yokohama, Japan
Other:
University of Texas Institute for Geophysics, United States
JAPEX Overseas Exploration, Japan
Volume Title: AGU 2006 fall meeting
Source: Eos, Transactions, American Geophysical Union, 87( Fall Meeting Suppl.); American Geophysical Union 2006 fall meeting, San Francisco, CA, Dec. 11-15, 2006. Publisher: American Geophysical Union, Washington, DC, United States. ISSN: 0096-3941 CODEN: EOSTAJ
Note: In English. Accessed on Oct. 16, 2007
Summary: In preparation for the NanTroSEIZE IODP drilling campaign, we conducted an ≈ 570- km 2 commercial 3D seismic reflection survey in the Kumano Basin, Nankai Trough, Japan. The survey was carried out during April-May, 2006 by Petroleum GeoServices (PGS) with the S/V Nordic Explorer using 4 hydrophone cables of 4500 m spaced 150 m apart and two G-gun arrays of 3090 in3. Firing the G-gun arrays alternately yielded 8 CMP lines per sail line with 6.25 m x 37.5 m CMP spacing. Processing by PGS included noise and multiple attenuation, flex-binning, alternate inline trace sum, 3D DMO and stack, inline interpolation and 3D post-stack migration to yield 635 inlines at 18.75 m spacing and 4500 crosss-lines at 12.5 m spacing. The 3D volume images the ocean crust to a depth of 8.5 sec (≈ 11 km). Thrust packages in the frontal accretionary prism are highly variable along strike, partly because of disruption by a subducting seamount. The décollement is a strong, continuous positive-polarity reflection through most of the frontal region. A megasplay fault rises from the oceanic crust at >7sec (≈ 10 km) depth, cutting across the older part of the accretionary prism all the way to the seafloor in the frontal accretionary thrust region. This splay fault reflection exhibits areas of reverse polarity, possibly reflecting fluid flow from the seismogenic zone to the surface. More than 2 sec of sediment in the Kumano forearc basin are imaged. The deepest part of the section is strongly folded, while the seaward portion is progressively tilted landward due to repeated motion on the megasplay fault.
Year of Publication: 2006
Research Program: IODP Integrated Ocean Drilling Program
Key Words: 18 Geophysics, Solid-Earth; 20 Geophysics, Applied; Accretionary wedges; Arrays; Basins; Crust; Decollement; Deformation; Faults; Fore-arc basins; Geophysical methods; Geotraverses; Imagery; Integrated Ocean Drilling Program; Kumano Basin; NanTroSEIZE; Nankai Trough; North Pacific; Northwest Pacific; Oceanic crust; Pacific Ocean; Reflection methods; Seismic methods; Subduction zones; West Pacific
Record ID: 2009096185
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute.

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