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Tateishi, Ryo*; Shimada, Koji; Iwamori, Akiyuki*; Wada, Shinya*; Seno, Shotaro*; Nagata, Ken*
Chishitsugaku Zasshi (Internet), 128(1), p.63 - 64, 2022/04
The Tsuruga Fault is an active right-lateral strike-slip fault that is about 20 km in length and distributed in the northeast-southwest direction from the eastern part of Tsuruga City to the southern part of Mihama Town, Fukui Prefecture. The Tsuruga fault borders the Jurassic accretionary complex (mixed rock) and the late Cretaceous granite around the Oritodani area in the Shinjo district of Mihama-cho. Lateral bendings of valleys along the fault in this area are clear geomorphological signatures of fault activity. We briefly report newly found multiple fault outcrops at these bending points with photos of them. This research is the result of joint research by Kansai Electric Power Company, University of Toyama, and JAEA.
Tateishi, Ryo*; Shimada, Koji; Shimizu, Mayuko; Ueki, Tadamasa*; Niwa, Masakazu; Sueoka, Shigeru; Ishimaru, Tsuneari
Oyo Chishitsu, 62(2), p.104 - 112, 2021/06
We attempted to discriminate between active and non-active faults by linear discriminant analysis using the chemical composition data of fault gouges in Japan, and then examined the elements that represent the difference between them and better discriminants. As a result, the multiple discriminants obtained could discriminate between them with high probability. In addition, the generalization performance of these discriminants is discussed, and the discriminants that can be expected to have high discriminant performance for unknown samples are presented. Also, from the combination of elements common to these discriminants, we narrowed down the number of elements that represent the difference between active and non-active faults to 6, and showed that the combination of TiO
and Sr contributing the most to the discrimination. The method applied in this study is an innovative one that can discriminate the activity by chemical analysis of fault rocks that are universally present in the bedrock.
Yasue, Kenichi; Shimada, Koji; Sasaki, Akimichi; Tanaka, Yukumo; Niwa, Masakazu; Ishimaru, Tsuneari; Umeda, Koji; Tateishi, Ryo*; Kosaka, Hideki*
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no abstracts in English
Ishimaru, Tsuneari; Shimada, Koji; Niwa, Masakazu; Yasue, Kenichi; Tateishi, Ryo*; Ikeda, Makinori; Umeda, Koji
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Tateishi, Ryo
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Shimada, Koji; Tateishi, Ryo*
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We need a method to assess the activity of crush zones alternative to the application of overlying sediments, because the zones encountered in underground tunnels and boring have unknown extensions to the ground surface. The method to be developed is one in which the result is objective and independent of the person, which helps professional judgment. In addition, implementation, dissemination and verification must be executable by a general geological engineer. In light of these goals, the whole-rock chemical composition of the fault gouge along a principal slip zone of the crush zone is attractive. Is there any difference in the chemical composition of fault rocks between active and inactive faults? We thought that the utilization of multivariate analysis could be a solution. Therefore, we collected literature values of the chemical composition of fault gouges for faults with known activities, and began searching for a primary equation that distinguishes active from non-active faults by multivariate analysis in 2018. The results of studies on granitic rocks show that there are multiple discriminants that separate active and non-active faults with a discrimination rate of 100%. In the presentation, we would like to introduce the current status of initiatives, including past case studies.
Iwamori, Akiyuki*; Ogita, Yasuhiro; Shimada, Koji; Tateishi, Ryo*; Takagi, Hideo*; Ota, Toru*; Kanno, Mizuho*; Wada, Shinya*; Ono, Akihiro*; Otsuka, Yoshiharu*
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We investigated the W value, which is an index showing the progress of weathering, for the fault rocks in the Kojak granite distributed in the eastern Wakasa area. The W value represents the contribution due to weathering calculated from the chemical composition, and along with the M value (contribution of the mafic component) and F value (contribution of the felsic component), a triangular diagram of M + F + W = 100% showing trends from protolith to fault rocks (cataclasite or fault gouge) can be drown. We also investigated on the fault at the geological boundary between the Kojaku granite and the Mino-Tamba metabasalt, and on the difference in characteristics from the fault rock in the Kojaku granite. Granite protolith has an F value of 94.2% and W value of 4.9%, and the fault rock sample has an M value of about 3% regardless of whether it is an active fault or an inactive fault. As weathering progresses, the F value decreases and the W value increases. Metabasalt has an M value of 88.2% and a W value of 6.6%, and the cataclasite has an almost constant F value. As weathering progresses, the M value decreases and the W value increases. Some of the F value increases with the increase of the W value, which is consistent with the contamination of granite-origin quartz fragments found in the basaltic fault gouge. As a result of examination, it was confirmed that NaO and CaO have a great influence on the increase and decrease of the W value.
Tateishi, Ryo*; Shimada, Koji; Ueki, Tadamasa; Shimizu, Mayuko; Komatsu, Tetsuya; Sueoka, Shigeru; Niwa, Masakazu; Yasue, Kenichi*; Ishimaru, Tsuneari
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no abstracts in English
Shimada, Koji; Tateishi, Ryo*; Ishimaru, Tsuneari; Sasaki, Akimichi; Tanaka, Yukumo; Miyazaki, Masashi; Yasue, Kenichi; Niwa, Masakazu; Sueoka, Shigeru; Umeda, Koji; et al.
no journal, ,
Activity evaluation of crush zones encountered in basement rock is an issue of the seismic safety assessment of nuclear plant and geological isolation of radioactive wastes. The selection of crush zone of which has been evaluated should be defined as the latest one by means of turn determination of crush zone activity based on stratigraphic or structural geological method. A lesson from granitic basement rock (Kojaku granite) holding the fast breeder reactor "Monju" is presented. The Kojaku Granite form the oval Tsuruga peninsula (ca. 8km in width) on the southeastern coast of the Sea of Japan and the age is 68.5 plus/minus 0.7Ma (Zircon U-Pb age).1. Stratigraphy-oriented turn determination of crush zone activity. (1.1) Turn determination using cover sediments. (1.2) Turn determination using dyke, mineral and clay vein. 2. Structural-oriented turn determination of crush zone activity.
Sasaki, Akimichi; Yasue, Kenichi; Shimada, Koji; Tateishi, Ryo*; Ishimaru, Tsuneari; Tanaka, Yukumo
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no abstracts in English
Tateishi, Ryo*; Shimada, Koji; Shimizu, Mayuko; Sueoka, Shigeru; Niwa, Masakazu; Ishimaru, Tsuneari
no journal, ,
The identification of active faults is based on the displacement and deformation of the current topography and the late Quaternary strata. However, in the absence of them, it is difficult to determine the fault activity. To solve this problem, multivariate analysis was performed using chemical composition data of fault gouges of active and inactive faults in Japan. We performed linear discriminant analysis with a following combination of elements; (a) 11 elements selected by AIC, (b) 8 elements with p-value between 0 and 0.01, (c) 6 elements with p-value between 0 and 0.001. The discrimination rate between active faults and inactive faults is 100% in (a), (b) and 97% in (c). Among elements that represent the difference, TiO and PO
, and AlO
and Rb are considered important, including their respective combinations. These results contribute to clarify the mechanism that creates the difference in chemical composition between active and inactive faults.
Iwasawa, Saeko*; Nakamura, Kosuke*; Yasue, Kenichi*; Tateishi, Ryo*; Terakado, Ryuji*; Kagohara, Kyoko*; Niwa, Masakazu; Kurosawa, Hideki*
no journal, ,
The Taie Fault is one of active faults in the Hida area, Gifu Prefecture, central Japan. This study revealed spatial distribution and displacement rate of the Taie Fault based on aerial photograph interpretation, geologic survey, and radiocarbon dating.
Kanno, Mizuho; Niwa, Masakazu; Shimada, Koji; Tateishi, Ryo*
no journal, ,
It has been reported that there is a slight difference in the chemical composition of the whole rock between the fault gouge generated by fault activity and the uncrushed host rock. The reason for this is not clear, but since many fault gouges are rich in clay minerals, it is possible that the elements adsorbed on the surface of the clay minerals have some effect. Therefore, exchangeable cations were extracted by substituting cesium ions, which are easily adsorbed on the clay mineral surface, for the fault gaudis of active faults and inactive faults, and compared with the whole rock composition. A concentric logarithmic ratio transformation was used for the comparison. As a result, the concentration of inactive faults tended to be higher than that of active faults in Rb.
Ogita, Yasuhiro; Shimada, Koji; Ogawa, Masaya*; Nojiri, Keisuke*; Shigemitsu, Yasumune*; Iwamori, Akiyuki*; Tateishi, Ryo*
no journal, ,
no abstracts in English
Sawada, Nagisa*; Tateishi, Ryo*; Kawasaki, Kazuo*; Seno, Shotaro*; Shimada, Koji; Iwamori, Akiyuki*; Ogawa, Masaya*
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Kamataki, Takanobu*; Tateishi, Ryo*; Yasue, Kenichi
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Seno, Shotaro*; Sawada, Nagisa*; Tateishi, Ryo*; Shimada, Koji; Iwamori, Akiyuki*; Ogawa, Masaya*
no journal, ,
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Tateishi, Ryo
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Tateishi, Ryo*; Shimada, Koji; Niwa, Masakazu; Sueoka, Shigeru; Shimizu, Mayuko; Kanno, Mizuho; Ishii, Chikako; Ishimaru, Tsuneari
no journal, ,
The major difference between active faults and inactive faults is the elapsed time after the latest activity, and while active faults are considered to be on the order of 
to 
years, inactive faults are over 
years. Therefore, even if the phenomena caused by fault activity are the same in both cases, the chemical changes that occur during the subsequent rest period of fault activity may differ significantly. In this study, the chemical composition of fault clay was collected by literature values and actual analysis, and the feasibility of discrimination by the chemical composition examined by linear discriminant analysis. According to the 11 elements selected based on the AIC, 45 active fault samples and 51 inactive fault samples were identified with a discrimination rate of 96%. Among the elements, TiO and PO tended to be concentrated as the latest activity period was newer. These concentration mechanisms are for future work.
Tateishi, Ryo*; Shimada, Koji; Iwamori, Akiyuki*; Ogita, Yasuhiro; Wada, Shinya*; Kunimatsu, Wataru*; Otsuka, Yoshiharu*
no journal, ,
It has been demonstrated that active faults (strike-slip faults) and non-active faults developed in granitic rocks in Japan can be discriminated with high probability by linear discriminant analysis using chemical compositions of fault gouge samples. Although, the result included that a reverse fault type active fault was discriminated on the inactive fault side. In this study, to confirm whether this result is due to the difference in fault type or the difference in rock body, chemical composition and linear discriminant analysis of the fault gouge of active reverse faults, active strike-slip faults, and non-active faults in the Kojyaku granite were carried out. As a result, the discrimination rate between active and inactive faults was 100% for 13 (chemical) components and 7 components selected by AIC, and 90% for 3 components. This result suggests the possibility that the difference in the granite bodies affected the discrimination more than the difference of their fault type.
Seno, Shotaro*; Tateishi, Ryo*; Shimada, Koji; Iwamori, Akiyuki*; Ogawa, Masaya*
no journal, ,
Several new outcrops of the Tsuruga Fault were discovered through field surveys near the fault distribution location using topographical interpretation using 1mDEM. In one outcrop, a layer of gravel is wrapped around a fractured zone of basement rock. From these sediments the K-Ah and the AT were detected through tephra analysis of fine grained portions. From the horizontal spread of the gravel layer at this outcrop and the attitude of the fault line, we determined the lower limit of the sum of multiple displacements for the horizontal component, diagonal slip component, and vertical component. The lower limit of the average displacement rate was calculated by dividing each component by the age of K-Ah. The results revealed that the vertical component is approximately 0.7m per 1000 years, the horizontal component is approximately 1.4m per 1000 years, and the diagonal component is approximately 1.5m per 1000 years.
