HR: 1340h
AN: T53A-1128    [Abstracts]
TI: First Results From NanTroSEIZE Logging While Drilling, IODP Expedition 314: Fault Zone and Thrust Sheet Structural Synthesis
AU: * Tobin, H
EM: htobin@wisc.edu
AF: Dept. of Geology and Geophysics, Un. of Wisconsin-Madison, Madison, WI 53706, United States
AU: Kinoshita, M
EM: masa@jamstec.go.jp
AF: IFREE, JAMSTEC, Yokosuka, PA 237-0061, Japan
AU: Expedition 314 Scientific Party, I
AB: Integrated Ocean Drilling Program (IODP) Expedition 314 is both the maiden scientific voyage of the new drilling vessel Chikyu and the first leg in the Nankai Trough Seismogenic Zone Experiment (NanTroSEIZE), a multi-year effort designed to investigate fault mechanics and seismogenesis along a subduction megathrust through direct sampling, in situ measurements, and long-term monitoring. During Expedition 314, which takes place September through November, 2007, our primary goals are to obtain a comprehensive suite of geophysical logs and other downhole measurements at six sites along a transect focused on the up-dip transition from seismic to aseismic fault behavior, using state-of-the-art logging-while-drilling (LWD) techniques. The sites include sampling to depths of 600 to more than 1000 m of a major out-of-sequence thrust system (the "megasplay" fault), thought to be connected to the seismogenic portion of the plate boundary, as well as incoming plate trench sediments, the frontal thrust of the accretionary prism, forearc basin deposits, and highly-deformed rocks of the interior of the accretionary prism. The principal goals of the LWD program are to document in situ physical properties, lithostratigraphic and structural features, sonic to seismic scale velocity data for core-log-seismic integration, and parameters related to stress, pore pressure, and hydrological properties. A synthesis of results bearing on the structural geology, lithology, and in situ stress conditions of the sediments and faults of the Nankai Trough will be presented. Resistivity image logs will elucidate fault zone structure as well as possible borehole breakouts, and multi-parameter log interpretation will document lithology and permit integration with 3D seismic reflection imaging.
UR: http://www.iodp.org/nantroseize
DE: 3036 Ocean drilling
DE: 8010 Fractures and faults
DE: 8104 Continental margins: convergent
DE: 8118 Dynamics and mechanics of faulting (8004)
SC: Tectonophysics [T]
MN: 2007 Fall Meeting