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Niwa, Masakazu; Kurosawa, Hideki*; Kosaka, Hideki*; Ikuta, Masafumi*; Takatori, Ryoichi*
JAEA-Data/Code 2017-009, 71 Pages, 2017/06
JAEA-Data-Code-2017-009.pdf:13.8MB
JAEA-Data-Code-2017-009-appendix(CD-ROM).zip:50.09MB
Changes of stress state due to the 2011 off the Pacific Coast of Tohoku Earthquake triggered normal displacements of faults that have not been regarded as active faults. In this study, geological survey for normal faults in coastal region was conducted in order to understand the mechanism of reactivation of inactive faults triggered by megathrust earthquakes. This report includes topographical and geological data obtained by field works in and around the Kawaminami Fault in northern margin of the Miyazaki Plain, with results of microscopic examination, analyses of X-ray diffraction and particle size distribution for clayey samples, analyses of tephra and plant opal, and radiocarbon dating.
Niwa, Masakazu; Kurosawa, Hideki; Shimada, Koji; Ishimaru, Tsuneari; Kosaka, Hideki*
Pure and Applied Geophysics, 168(5), p.887 - 900, 2011/07
Times Cited Count：2 Percentile：10.03(Geochemistry & Geophysics)Previous studies have reported that high concentrations of H
gas are released from active fault zones. Experimental studies suggest that the H gas is derived from the reaction of water with free radicals formed when silicate minerals are fractured at hypocenter depths during fault activities. Based on the H gas measurements and the particle size distribution analyses, the deep-seated H gas is considered to have migrated in permeable damage zones mostly by advection with groundwater. Multipoint H gas measurement will be effective in delineating qualitatively, variations in permeability of regional structures.
Tokiwa, Tetsuya; Asamori, Koichi; Niizato, Tadafumi; Nohara, Tsuyoshi; Matsuura, Yuki*; Kosaka, Hideki*
Proceedings of 13th International Conference on Environmental Remediation and Radioactive Waste Management (ICEM 2010) (CD-ROM), p.407 - 413, 2010/10
In this study, we present the preliminary results for the estimation of a horizontal crustal movement by using geodetic and geological approach in the Horonobe area, northern Hokkaido, Japan. The estimations have been carried out by using a GPS data and a geological cross section obtained by applying balanced-section method. As results of this study, both of the shortening rates estimated by GPS data and balanced-section method indicate several millimeters per year. Namely, there is no contradiction between geodetic and geological data, and it is considered that Horonobe area is still situated similar tendency and magnitude of a crustal movement. Geodetic data is not usually used to evaluate the long-term crustal movement. However, the results of this study indicate that geodetic data provide valuable information for estimating the long-term crustal movement in the area.
Kurosawa, Hideki; Ishimaru, Tsuneari; Shimada, Koji; Niwa, Masakazu; Kosaka, Hideki*; Saito, Satoshi*; Ninomiya, Atsushi
JAEA-Research 2009-043, 144 Pages, 2010/01
JAEA-Research-2009-043-01.pdf:8.09MBJAEA-Research-2009-043-02.pdf:46.22MB
Research on the influence of fault activity on deep geological environments contributes to the reliability of geological disposal systems for HLW. In this study, preliminary test shows that measured value within 1 hour after measurement start is supposed to include hydrogen gas generated by rock fracturing during the drilling of sampling holes and that stored in surrounding disturbed rocks, though the monitoring from a hand-drilled hole is effective for a rapid measurement. We investigated the concentration of hydrogen gas emitted from the Yamasaki fault zone, in southeast Japan. In our survey, the points where high concentrations of hydrogen gas emission was detected were unevenly distributed along the active fault, and in the southeast portion of the study area where small earthquakes frequently occurred.
Kosaka, Hideki*; Kagohara, Kyoko; Miwa, Atsushi*; Imaizumi, Toshifumi*; Kurosawa, Hideki; Nohara, Tsuyoshi
Chigaku Zasshi, 117(5), p.851 - 862, 2008/10
To understand the development process of the fault zone, fission-track ages of rocks and rock facies are investigated in western margin of the Ou Backbone Range of Northeast Japan. Fission-track dating was carried out for 5 acid volcanic rocks from the late Pliocene to Pleistocene strata which were deposit associated with mountain belt growth. Statistically significant ages obtained are 1.5
0.1 Ma (OB-03) and 1.850.1 Ma (YG-01) for the Tazawa Formation, 1.60.3 Ma (FT-01) for the Kurisawa Formation,0.930.14 Ma (FT-02) and 2.70.3 Ma (FT-03) for the Senya Formation. According to the fission-track dating in this study, ages of the mountain belt growth with acid volcanic activity are estimated to before 1 Ma.
Kagohara, Kyoko*; Imaizumi, Toshifumi*; Miyauchi, Takahiro*; Sato, Hiroshi*; Uchida, Takuma*; Echigo, Tomoo*; Ishiyama, Tatsuya*; Matsuta, Nobuhisa*; Okada, Shinsuke*; Ikeda, Yasutaka*; et al.
Chigaku Zasshi, 115(6), p.691 - 714, 2006/12
The eastern marginal fault zone of the Yokote Basin is one of seismogenic reverse faults developed in Northeast Japan, generating the 1896 Riku-u Earthquake (M7.2). We discussed the relationship among fault traces, geomorphic displacements and fault geometries on the Senya fault, based on a data from high-resolution seismic reflection profiling, investigations in tectonic geomorphology and structural geology, with the help of the balanced cross section method. By the restoring the balanced cross sections, the horizontal shortening amount is estimated to be totally 3 km through the thrust system, and the thrusting is retroactive to 2.4 Ma. Depending on the strike of fault traces and the morphotectonic features, the Senya fault is subdivided into three, the northern, central and southern portion. The initiation of thrust front migration is ca.1.6 Ma at the central portion and 0.6 Ma at the northern portion. This means that the central portion preceded the northern portion as an emergent fault, and suggests that the initial propagated fault extends from the fault end to the boundary fault.
Imaizumi, Toshifumi*; Kagohara, Kyoko*; Otsuki, Kenshiro*; Miwa, Atsushi*; Kosaka, Hideki*; Nohara, Tsuyoshi
Katsudanso Kenkyu, (26), p.71 - 77, 2006/06
no abstracts in English
Niwa, Masakazu; Shimada, Koji; Kurosawa, Hideki; Ishimaru, Tsuneari; Kosaka, Hideki*
no journal, ,
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.
Ishimaru, Tsuneari; Shimada, Koji; Niwa, Masakazu; Kurosawa, Hideki; Kosaka, Hideki*
no journal, ,
Hydrogen gas measurements have been carried out in active faults, for assessments of fault activities or earthquake prediction. Recently, Shimada et al. (2008) invented the new method by use of a portable hydrogen gas monitor, allowing measurements in many localities over a short amount of time. We examine the applicability of this method to understanding the feature of fractures as a conduit-barrier system and their linkage with active faults. In this presentation, we show a case study of the measurements in the Atotsugawa Fault, Gifu Prefecture.
Kagohara, Kyoko; Kurosawa, Hideki; Kosaka, Hideki*; Ishimaru, Tsuneari
no journal, ,
no abstracts in English
Kagohara, Kyoko; Kurosawa, Hideki; Kosaka, Hideki*; Ishimaru, Tsuneari
no journal, ,
no abstracts in English
Ishimaru, Tsuneari; Kurosawa, Hideki; Kosaka, Hideki*; Niwa, Masakazu; Shimada, Koji
no journal, ,
no abstracts in English
Kurosawa, Hideki; Ishimaru, Tsuneari; Kagohara, Kyoko; Kosaka, Hideki*; Shimada, Koji
no journal, ,
no abstracts in English
Niwa, Masakazu; Kurosawa, Hideki; Shimada, Koji; Ishimaru, Tsuneari; Kosaka, Hideki*
no journal, ,
no abstracts in English
Ikuta, Masafumi; Niwa, Masakazu; Takatori, Ryoichi; Kurosawa, Hideki*; Kosaka, Hideki*
no journal, ,
Although there are several normal faults in coastal area on the Pacific side, normal faulting triggered by a large earthquake in plate convergence has never been reported until the earthquake in Fukushima, April 11, 2011. Therefore more case studies focused on normal faults are needed to assess the risk of fault activity in coastal areas. As such case study, we are doing geological and topographical surveys in the Kawaminami Fault, lying along the northern margin of the Miyazaki Plain.
Yasue, Kenichi; Shimada, Koji; Sasaki, Akimichi; Tanaka, Yukumo; Niwa, Masakazu; Ishimaru, Tsuneari; Umeda, Koji; Tateishi, Ryo*; Kosaka, Hideki*
no journal, ,
no abstracts in English
