Japan Geoscience Union Meeting 2015

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Symbol S (Solid Earth Sciences) » S-CG Complex & General

[S-CG61] Crustal fluids and deformation

Wed. May 27, 2015 2:15 PM - 3:00 PM 102B (1F)

Convener:*Naoji Koizumi(Geological Survey of Japan, National Institute of Advanced Industrial Science and Technology), Koji Umeda(Tono Geoscience Center,Japan Atomic Energy Agency), Norio Matsumoto(Tectono-Hydrology Research Group, Geological Survey of Japan, National Institute of Advanced Industrial Science and Technology (AIST)), Hidemi Tanaka(School of Science, The University of Tokyo), Kohei Kazahaya(Geological Survey of Japan, AIST), Fumiaki Tsunomori(Laboratory for Earthquake Chemistry, Graduate School of Science, University of Tokyo), Chair:Norio Matsumoto(Tectono-Hydrology Research Group, Geological Survey of Japan, National Institute of Advanced Industrial Science and Technology (AIST)), Naoji Koizumi(Geological Survey of Japan, National Institute of Advanced Industrial Science and Technology)

2:45 PM - 3:00 PM

[SCG61-09] In-situ measurement of permeability of fault zones by hydraulic tests and continuous groundwater-level observation

*Norio MATSUMOTO1, Norio SHIGEMATSU1 (1.GSJ, AIST)

Keywords:permeability, fault zone, hydraulic test, groundwater level

GSJ, AIST constructed an integrated groundwater observatory at Matsusaka-Iitaka as a part of the groundwater and crustal deformation observation network for the prediction research of the Nankai and Tonankai earthquakes (Shigematsu et al., 2012; Koizumi, 2013). Hole 1 (total depth 600m) was penetrated the Median Tectonic Line (MTL) at a depth of 473.9m. Total depth of Hole 2 is 208m. We obtained core samples and well logging data and conducted hydraulic tests in these wells. Screened depth of Hole 1 is 547.6 - 558.5 m and is located in the lower fracture zone of the MTL fault zone developed in the Sanbagawa metamorphic rocks. Screened depth of Hole 2 is 145.5-156.4 m and is located at a branch fault in the Ryoke Granitolds (Shigematsu et al., 2012).
The results of the hydraulic tests and continuous groundwater observation show 1.8 - 8.5 x 10 -16 and 1.8 x 10-15 m2 in Hole 1 and Hole 2, respectively. These permeabilities are consistent with laboratory permeability measurement of MTL fault rocks (Wibberley and Shimamoto, 2003).