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Composition, Microstructures, And Petrophysics Of The Mozumi Fault, Japan: In Situ Analyses Of Fault Zone Properties And Structure In Sedimentary Rocks From Shallow Crustal Levels, Angela J. Isaacs, James P. Evans, Peter T. Kolesar, Tsuyoshi Nohara
Composition, Microstructures, And Petrophysics Of The Mozumi Fault, Japan: In Situ Analyses Of Fault Zone Properties And Structure In Sedimentary Rocks From Shallow Crustal Levels, Angela J. Isaacs, James P. Evans, Peter T. Kolesar, Tsuyoshi Nohara
Geosciences Faculty Publications
[1] We characterize the chemical, microstructural, and geophysical properties of fault-related rock samples from the 80–100 m wide Mozumi fault zone, north central Honshu, Japan. The fault is exposed in a research tunnel 300–400 m below the ground, and we combine geological data with borehole geophysical logs to determine the elastic and seismic properties of the fault zone. Detailed mapping within the tunnel reveals that the fault zone consists of two zones of breccia to foliated cataclasites 20 and 50 m thick. Two narrow (tens of centimeters wide) principal slip zones on which most of the slip occurred bound the …
Hydrologic Properties And Structure Of The Mozumi Fault, Central Japan, Craig B. Forster, James P. Evans, Hidemi Tanaka, Ronald Jeffreys, Tsuyoshi Nohara
Hydrologic Properties And Structure Of The Mozumi Fault, Central Japan, Craig B. Forster, James P. Evans, Hidemi Tanaka, Ronald Jeffreys, Tsuyoshi Nohara
Geosciences Faculty Publications
Analyses of rocks from the Active Fault Survey Tunnel (AFST) provides insight into the structure and hydrogeology of the northeast-trending Mozumi-Sukenobu fault, an active strike-slip fault with 125 to 500 m of right-lateral slip in central Japan. Interlayered regions of sub-vertical permeability zones formed by cataclasis and slip on clay-rich foliated zones. Core samples range from 10−19 m2 to almost 10−13 m2. CFC analyses of waters from the fault zone show that water entering the tunnel is 27–36 years old, yielding a bulk fault permeability of 10−14 to 10−15 m2. The …