HR: 0800h
AN: T41F-1290    [Abstracts]
TI: Temporal change in permeability of the Nojima fault zone after the 1995 Hyogoken-Nanbu earthquake
AU: * Kitagawa, Y
EM: y-kitagawa@aist.go.jp
AF: Geological Survey of Japan, AIST, Site C7, 1-1-1 Higashi, Tsukuba, 305-8567 Japan
AU: Fujimori, K
EM: fujimori@kugi.kyoto-u.ac.jp
AF: Graduate School of Science, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto, 606-8502 Japan
AU: Koizumi, N
EM: koizumi-n@aist.go.jp
AF: Geological Survey of Japan, AIST, Site C7, 1-1-1 Higashi, Tsukuba, 305-8567 Japan
AB: Three boreholes were drilled near the Nojima fault, which the 1995 Hyogoken-Nanbu earthquake occurred on. In order to research the properties and the fault healing process of the fault, the water injection experiments were conducted in every three years. In this report, we researched the permeability of the fault as a measure of the fractured state of the fault. The pore water pressure changes in rock due to the water injection experiments were observed as the discharge changes from the borehole or the groundwater level changes at the borehole. Using the numerical calculation, the permeability of the fault fracture zone was estimated at each experiment. The permeability has been decreasing as time passed and the fact is thought to show the fault healing process of the Nojima fault after the 1995 Hyogoken-Nanbu earthquake.
DE: 8010 Fractures and faults
DE: 5104 Fracture and flow
DE: 5114 Permeability and porosity
DE: 1829 Groundwater hydrology
SC: Tectonophysics [T]
MN: 2004 AGU Fall Meeting