Geological investigations using cosmic ray muons; A Trial to detect fault at the Mizunami Underground Research Laboratory

Sasao, Eiji; Suzuki, Keiichi*; Yamada, Nobuto*; Kuboshima, Koji*

Proceedings of 12th SEGJ International Symposium (USB Flash Drive), 4 Pages, 2015/11

We performed investigation of a fault with thick and clay-altered damaged zone in granitic rock using cosmic ray muons at the Mizunami Underground Research Laboratory. Geology of the Laboratory consists of sedimentary rock and underlying granite with unconformable contact at the 170 meters below ground level (G.L.). A vertical fault with a thick, clay-altered damaged zone is present in the granite. The muon telescopes were settled at the G.L.-200 and -300 meters to estimate densities of granite and fault. Densities of granite, fault and sedimentary rock are calculated as 3.38, 2.88 and 1.99 g/cm, respectively. The obtained density is obviously higher than absolute value, though the reason of such difference is not clear at the moment. If the density of granite is assumed to be 2.6 g/cm, then the densities of fault and sedimentary rock are re-calculated as 2.2 and 1.5 g/cm. This result indicates that cosmic ray muons have good potential to detect geological structure.

Development of geological models in the Mizunami Underground Research Laboratory Project; Updating results of "Shaft460 geological model" and "shaft500 geological model" in Phase 2

Ishibashi, Masayuki; Sasao, Eiji; Kuboshima, Koji; Matsuoka, Toshiyuki

JAEA-Research 2013-019, 31 Pages, 2013/11

JAEA-Research-2013-019.pdf:11.64MB

Japan Atomic Energy Agency at Tono Geoscience Center is developing a geoscientific research project named the Mizunami Underground Research Laboratory (MIU) project in crystalline rock environment in order to establish scientific and technological basis for geological disposal of HLW. Geoscientific research at MIU is planned to be carried out in three phases; Surface-based Investigation Phase (Phase 1), Construction Phase (Phase 2) and Operation Phase (Phase 3). Currently, the project is under the Construction Phase (Phase 2) and the Operation Phase (Phase 3). In the phase 2, the geological models have been updated six times (Shaft180, Pilot500, Substage200, Stage300, Shaft460 and Shaft500 geological model) based on the increasing data. The updating result from Shaft180 geological model to Stage300 geological model was already published. Thus this document mainly describes Shaft460 and Shaft500 geological models at the Phase 2.

Study on geology on the Mizunami Underground Research Laboratory Project; Geology and geological structure from the surface to G.L. -300m

Kuboshima, Koji; Ishibashi, Masayuki; Sasao, Eiji; Tsuruta, Tadahiko; Tagami, Masahiko*; Yuguchi, Takashi

JAEA-Research 2012-037, 78 Pages, 2013/03

JAEA-Research-2012-037.pdf:235.85MB

The MIU (Mizunami Underground Research Laboratory) Project has three overlapping phases, Surface-based investigation phase (Phase I), Construction phase (Phase II), and Operation phase (Phase III). Currently, the project is under Phase II and Phase III. One of Phase II goals is set up to develop and revise models of the geological environment using the investigation results obtained during excavation, and to determine and assess changes in the geological environment in response to excavation. This report aims compiling results of study on geology and geological structure from the surface to G.L. -300m in the Phase II and provides the fundamental information on the geology and geological structure for future study. The compiling results of this report reflected basic data are utilized in the updating of the geological models in the Phase II.

Mizunami Underground Research Laboratory Project, Plan for fiscal year 2012

Kunimaru, Takanori; Mikake, Shinichiro; Nishio, Kazuhisa; Tsuruta, Tadahiko; Matsuoka, Toshiyuki; Ishibashi, Masayuki; Kuboshima, Koji; Takeuchi, Ryuji; Mizuno, Takashi; Sato, Toshinori; et al.

JAEA-Review 2012-028, 31 Pages, 2012/08

JAEA-Review-2012-028.pdf:3.86MB

Japan Atomic Energy Agency (JAEA) at Tono Geoscience Center (TGC) is pursuing a geoscientific research and development project namely the Mizunami Underground Research Laboratory (MIU) project in crystalline rock environment in order to construct scientific and technological basis for geological disposal of High-level Radioactive Waste (HLW). The MIU project is planned in three overlapping phases; Surface-based Investigation Phase (Phase I), Construction Phase (Phase II) and Operation Phase (Phase III). Currently, the project is under the Construction Phase and the Operation Phase. This document introduces the research and development activities planned for 2012 fiscal year based on the MIU Master Plan updated in 2010, construction plan and research collaboration plan, etc.

Mizunami Underground Research Laboratory Project; Compilation of results of the borehole investigation at research galleries and shaft

Ueno, Takashi; Tokuyasu, Shingo; Kawamoto, Koji; Kuboshima, Koji; Ishibashi, Masayuki; Tsuruta, Tadahiko; Sasao, Eiji; Ikeda, Koki; Mikake, Shinichiro; Hara, Ikuo; et al.

JAEA-Data/Code 2012-008, 136 Pages, 2012/07

JAEA-Data-Code-2012-008.pdf:27.39MB
JAEA-Data-Code-2012-008(errata).pdf:1.55MB
JAEA-Data-Code-2012-008-appendix(DVD-ROM)-1.zip:790.9MB
JAEA-Data-Code-2012-008-appendix(DVD-ROM)-2.zip:834.48MB
JAEA-Data-Code-2012-008-appendix(DVD-ROM)-3.zip:533.98MB
JAEA-Data-Code-2012-008-appendix(DVD-ROM)-4.zip:712.56MB
JAEA-Data-Code-2012-008-appendix(DVD-ROM)-5.zip:525.5MB

This report compiles data of results from borehole investigations which has been carried out research gallery of Mizunami Underground Research Laboratory (MIU) in the fiscal year from 2005 to 2011. These data include results of core observation, geophysical logging, and so on.

Structual evolution of NW-SE fault in Mizunami underground research laboratry; Imformation from analysis of horizontal borehole core in horizontal tunnnel

Kuboshima, Koji; Ishibashi, Masayuki; Sasao, Eiji; Tsuruta, Tadahiko

no journal, , 

no abstracts in English

Mizunami Underground Research Laboratory Project; Geological investigations

Ishibashi, Masayuki; Kawamoto, Koji; Kuboshima, Koji; Kuroiwa, Hiroshi; Sasao, Eiji; Tsuruta, Tadahiko; Matsuoka, Toshiyuki

no journal, , 

no abstracts in English

Fault exploration based on the microcrack distribution pattern; The Example of the Tsukiyoshi fault, central Japan

Otani, Tomoyuki*; Okazaki, Kazunari*; Nishimura, Yuki*; Kojima, Satoru*; Kuboshima, Koji; Sasao, Eiji; Tsuruta, Tadahiko

no journal, , 

no abstracts in English

Mizunami Underground Research Laboratory Project; Geological investigations

Sasao, Eiji; Yamada, Nobuto; Kuroiwa, Hiroshi; Kuboshima, Koji; Kawamoto, Koji; Ishibashi, Masayuki; Tsuruta, Tadahiko; Matsuoka, Toshiyuki; Murakami, Hiroaki

no journal, , 

no abstracts in English

Study on influence of fault activity to geological environment; Case study at the Mizunami Underground Research Laboratory

Sasao, Eiji; Ishibashi, Masayuki; Kuboshima, Koji*; Murakami, Hiroaki

no journal, , 

Understanding of a range influenced by fault activity is quite important, because fault activity could lead to form and/or grow crushed zone and to increase water conductivity. We described fracture frequency, fracture filling and alteration along fracture, and then discuss relationship between those features and fault at the Mizunami Underground Research Laboratory. As a result of the study, those features are dominant around faults in the Laboratory. Alteration along fracture and some of the fracture filling suggest inflow of hydrothermal fluid. This implies opening of fracture or reopening of existed fracture. We try to find the evidence of shear fracture in the future study, because fault activity would form shear fracture.