Path of hydrogen gas in fault zones

Niwa, Masakazu   ; Shimada, Koji   ; Kurosawa, Hideki; Ishimaru, Tsuneari ; Kosaka, Hideki*

Significantly high concentrations of hydrogen gas have been observed at active faults. Experimental studies have suggested that such hydrogen gas is generated by a radical reaction due to rock fracturing caused by fault activity. In this study, we tried multipoint hydrogen gas measurements along a fault zone crosscutting an active fault, to elucidate a path of hydrogen gas in fault zones. The result of the mesurements indicate that the hydrogen gas is transferred in the breccia and cataclasite of relatively-high permeability rather than in the smectite-rich fault gouge of low permeability, and strongly supports the hypothesis that a path of the hydrogen gas derived from fault activity is controlled by advective flow with groundwater.