In situ stress and pore pressure in the Kumano forearc basin, offshore SW Honshu from downhole measurements during riser drilling

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doi: 10.1002/ggge.20051
Author(s): Saffer, D. M.; Flemings, P. B.; Boutt, D.; Doan, M. L.; Ito, T.; McNeill, L.; Byrne, T.; Conin, M.; Lin, W.; Kano, Y.; Araki, E.; Eguchi, N.; Toczko, S.
Author Affiliation(s): Primary:
Pennsylvania State University, Department of Geosciences, University Park, PA, United States
Other:
University of Texas at Austin, United States
University of Massachusetts at Amherst, United States
Université Joseph Fourier, France
Tohoku University, Japan
University of Southampton, United Kingdom
University of Connecticut, United States
Centre Européen de Recherche et d'Enseignement des Géosciences de l'Environnement, France
Japan Agency for Marine-Earth Science and Technology, Japan
Kyoto University, Japan
Volume Title: Geochemistry, Geophysics, Geosystems - G<sup>3</sup>
Source: Geochemistry, Geophysics, Geosystems - G>3`, 14(5), p.1454-1470. Publisher: American Geophysical Union and The Geochemical Society, United States. ISSN: 1525-2027
Note: In English. 68 refs.; illus., incl. 3 tables
Summary: In situ stress and pore pressure are key parameters governing rock deformation, yet direct measurements of these quantities are rare. During Integrated Ocean Drilling Program (IODP) Expedition #319, we drilled through a forearc basin at the Nankai subduction zone and into the underlying accretionary prism. We used the Modular Formation Dynamics Tester tool (MDT) for the first time in IODP to measure in situ minimum stress, pore pressure, and permeability at 11 depths between 729.9 and 1533.9 mbsf. Leak-off testing at 708.6 mbsf conducted as part of drilling operations provided a second measurement of minimum stress. The MDT campaign included nine single-probe (SP) tests to measure permeability and in situ pore pressure and two dual-packer (DP) tests to measure minimum principal stress. Permeabilities defined from the SP tests range from 6.53 × 10-17 to 4.23 × 10-14 m2. Pore fluid pressures are near hydrostatic throughout the section despite rapid sedimentation. This is consistent with the measured hydraulic diffusivity of the sediments and suggests that the forearc basin should not trap overpressures within the upper plate of the subduction zone. Minimum principal stresses are consistently lower than the vertical stress. We estimate the maximum horizontal stress from wellbore failures at the leak-off test and shallow MDT DP test depths. The results indicate a normal or strike-slip stress regime, consistent with the observation of abundant active normal faults in the seaward-most part of the basin, and a general decrease in fault activity in the vicinity of Site C0009. Abstract Copyright (2013), . American Geophysical Union. All Rights Reserved.
Year of Publication: 2013
Research Program: IODP Integrated Ocean Drilling Program
Key Words: 07 Marine Geology and Oceanography; 20 Geophysics, Applied; Accretionary wedges; Asia; Basins; Crust; Downhole methods; Drilling; Expedition 319; Far East; Fluid phase; Fore-arc basins; Geophysical methods; Geophysical profiles; Geophysical surveys; Honshu; IODP Site C0009; In situ; Integrated Ocean Drilling Program; Japan; Kumano Basin; Lithosphere; Marine methods; Measurement; NanTroSEIZE; Nankai Trough; North Pacific; Northwest Pacific; Ocean floors; Oceanic crust; Oceanic lithosphere; Pacific Ocean; Permeability; Pore pressure; Seismic methods; Seismic profiles; Subduction zones; Surveys; West Pacific
Coordinates: N332728 N332728 E1363209 E1363209
N320000 N360000 E1383000 E1353000
Record ID: 2014019351
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