Kamioka Mine Research Articles

Shallow crustal permeability enhancement in central Japan due to the 2011 Tohoku earthquake

AbstractPore pressure decreased at the Kamioka mine in central Japan after the Tohoku earthquake (M9.0) on 11 March 2011, which can be attributed to a permeability increase. We focus on the Earth's tidal response before and after the earthquake to evaluate rock permeability change through hydraulic diffusivity change. If we assume a constant elastic modulus, hydraulic diffusivity is found to increase from 3.3 to 6.7 m2/s after the Tohoku earthquake. We also analyzed data before and after the 2007 Noto Hanto (M6.9) and 2008 Suruga Bay (M6.5) earthquakes, which yield no significant tidal response changes. We examined the amount of dynamic and static stress changes caused by these earthquakes and show that it is difficult to attribute the permeability enhancement solely to dynamic stress, and static stress change may also affect the permeability enhancement.

Excavation of an underground site for a km-scale laser interferometric gravitational-wave detector

KAGRA is a laser interferometric gravitational-wave detector with a 3 km arm length. It is to be constructed in the tunnels of the Kamioka mine in Hida, Gifu, Japan. The use of an underground site for small seismic motion is a key feature of KAGRA, as well as the use of a cryogenic technique to reduce any thermal noise. The KAGRA tunnels will have a total length of 7697 m and a total volume of 156 301 . Tunnel excavation work began in May 2012, and continued until the end of March 2014. The construction of the experiment rooms in the tunnels is currently ongoing, and installation of the vacuum system was planned to begin in July 2014. KAGRA will then start observations in 2018.

A 100-m Fabry–Pérot Cavity with Automatic Alignment Controls for Long-Term Observations of Earth’s Strain

We have developed and built a highly accurate laser strainmeter for geophysical observations. It features the precise length measurement of a 100-m optical cavity with reference to a stable quantum standard. Unlike conventional laser strainmeters based on simple Michelson interferometers that require uninterrupted fringe counting to track the evolution of ground deformations, this instrument is able to determine the absolute length of a cavity at any given time. The instrument offers advantage in covering a variety of geophysical events, ranging from instantaneous earthquakes to crustal deformations associated with tectonic strain changes that persist over time. An automatic alignment control and an autonomous relocking system have been developed to realize stable performance and maximize observation times. It was installed in a deep underground site at the Kamioka mine in Japan, and an effective resolution of 2 × (10−8 − 10−7) m was achieved. The regular tidal deformations and co-seismic strain changes were in good agreement with those from a theoretical model and a co-located conventional laser strainmeter. Only the new instrument was able to record large strain steps caused by a nearby large earthquake because of its capability of absolute length determination.

Evaluation of heat extraction through sapphire fibers for the GW observatory KAGRA

Currently, the Japanese gravitational wave laser interferometer KAGRA is under construction in the Kamioka mine. As one main feature, it will employ sapphire mirrors operated at a temperature of 20 K to reduce the impact from thermal noise. To reduce seismic noise, the mirrors will also be suspended from multi-stage pendulums. Thus the heat load deposited in the mirrors by absorption of the circulating laser light as well as heat load from thermal radiation will need to be extracted through the last suspension stage. This stage will consist of four thin sapphire fibers with larger heads necessary to connect the fibers to both the mirror and the upper stage. In this paper, we discuss heat conductivity measurements on different fiber candidates. While all fibers had a diameter of 1.6 mm, different surface treatments and approaches to attach the heads were analyzed. Our measurements show that fibers fulfilling the basic KAGRA heat conductivity requirement of κ ⩾ 5000 W m−1 K−1 at 20 K are technologically feasible.

Advanced natural gas storage system and verification tests of lined rock cavern - ANGAS project in Japan -

Technologies of an underground natural gas storage system, a Lined Rock Cavern (LRC) gas storage system called ANGAS (Advanced Natural GAs Storage), have been studied. The purpose of the project is to develop a suitable LRC system for Japan, and to contribute to expanding use of natural gas. It is necessary to study measures to shave off the daily peak load of natural gas through pipelines and it is expected that the ANGAS is one of key countermeasures for peak shaving. In the project, our goal is to ensure the design method of the LRC system under the Japanese geological conditions. One of the key technologies of the developed design method is based on plastic deformation of the steel liner considering the rock deformation appropriately. Using the developed design method and procedures, a small test cavern which is located at the Kamioka mine, the midland of Japan, was designed and constructed. The test cavern is surrounded by a sedimentary rock mass which consists of mainly sandstone and mudstone. The inner design pressure of the test cavern is 20MPa. In this paper, some results of the verification tests are presented and the validity of the LRC system for Japan is confirmed. Specifically, the steel liner was deformed up to its plastic zone, in order to be unified with the buffer material and the backfilled concrete as a hybrid structure. The displacements in the surrounding rock mass were stable under the inner design pressure 20MPa. Furthermore, the real crack intervals of the backfilled concrete are recognized to be less than the designed maximum interval and the real maximum crack width is inferred to be close to the designed one under 20 MPa pressure. Therefore, the design considering the crack properties of the back filled concrete has been verified.

Interferometer design of the KAGRA gravitational wave detector

KAGRA is a cryogenic interferometric gravitational wave detector being constructed at the underground site of Kamioka mine in Gifu prefecture, Japan. We performed an optimization of the interferomter design, to achieve the best sensitivity and a stable operation, with boundary conditions of classical noises and under various practical constraints, such as the size of the tunnel or the mirror cooling capacity. Length and alignment sensing schemes for the robust control of the interferometer are developed. In this paper, we describe the detailed design of the KAGRA interferometer as well as the reasoning behind design choices.

KamLAND-Zen: Status and Future

A high sensitivity neutrinoless double-beta (0νββ) decay experiment, KamLAND-Zen, has been taking data since last September using 330kg enriched 136Xe nuclei in Kamioka mine in Japan. The latest results on the half-life of 2ν and the limits on 0ν and Majoron-emitting decay modes obtained from the data corresponding to 38.6 kg yr exposure of 136Xe are reported followed by the current status and future prospects of the KamLAND-Zen.

R&D project for Gd-doped water Cherenkov detector

A dedicated test facility for a proposed Gadolinium doped water Cherenkov detector is being constructed in the Kamioka mine near the Super Kamiokande detector. Anti-electron neutrinos (v̄e) from inverse beta decay can be identified with high efficiency by taking advantage of Gd's large cross section on thermal neutron capture and by taking coincidence of a prompt positron and the delayed 8 MeV gamma cascades.

Detection of Supernova Neutrinos

Prospects for the future detection of supernova neutrinos are considered, with primary emphasis on water Cherenkov detectors. In particular, for the last seven years R&D on a potential upgrade to the Super–Kamiokande detector has been underway. Enriching Super–K with 100,000 kilograms of a water-soluble gadolinium compound – thereby enabling it to detect thermal neutrons and dramatically improving its performance, particularly as a detector for supernova neutrinos and reactor neutrinos – is discussed, as are some of the studies both ongoing and planned to help make this ambitious proposal a reality, including the construction of a large-scale, dedicated gadolinium testing facility in the Kamioka mine.

Role of experts and public participation in pollution control: the case of Itai-itai disease in Japan<sup>1

ESEP Ethics in Science and Environmental Politics Contact the journal RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections ESEP 12:99-111 (2012) - DOI: https://doi.org/10.3354/esep00126 Role of experts and public participation in pollution control: the case of Itai-itai disease in Japan1 Masanori Kaji Graduate School of Decision Science and Technology, Group of History of Science and Technology, Tokyo Institute of Technology, W9-79, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8552, Japan *Email: kaji.m.aa@m.titech.ac.jp ABSTRACT: Itai-itai disease was first noticed in the Junzu River basin region in Toyama prefecture in central Japan around the 1930s. However, it was not identified as a cadmium poisoning disease until the 1960s. A local physician, with cooperation from outside experts, confirmed that the disease was caused by pollution from the Kamioka mine (owned by the Mitsui Mining & Smelting Company Ltd) located in the upstream region of the river. In the mid-1960s, the victims of Itai-itai disease filed a suit against the company and won their case in 1972. The victims received compensation and signed a pollution control agreement with the company. The case of Itai-itai disease is a rare example of successful pollution control in Japan: the annual inspections of the ensuing 40 yr, based on the pollution control agreement, show a reduction of cadmium concentrations in the river to natural levels. By analyzing the roles of various experts involved, this case study has contributed substantially to an understanding of the nature of expertise and the significance of public participation in the resolution of environmental problems. 1The present publication is a revised and expanded version of papers in Japanese by Kaji (2005, 2009), published in English with permission of the copyright holder. KEY WORDS: Itai-itai disease · Pollution control · Cadmium · Public participation · Victims · Mining pollution Full text in pdf format PreviousNextCite this article as: Kaji M (2012) Role of experts and public participation in pollution control: the case of Itai-itai disease in Japan1. Ethics Sci Environ Polit 12:99-111. https://doi.org/10.3354/esep00126 Export citation Mail this link - Contents Mailing Lists - RSS Facebook - Tweet - linkedIn Cited by Published in ESEP Vol. 12, No. 2. Online publication date: July 06, 2012 Print ISSN: 1863-5415; Online ISSN: 1611-8014 Copyright © 2012 Inter-Research.

T2K: A LONG-BASELINE EXPERIMENT TO STUDY NEUTRINOS

T2K is the first of a new generation of long baseline neutrino oscillation experiments that will measure neutrino oscillations parameters. The experiment uses the J-PARC accelerator complex on the east cost of Japan to sent a neutrino beam to the Kamioka mine, located 295 km to the west. It consists of a dedicated beam-line, a near detector complex to characterize the beam and the well-known Super-Kamiokande detector to measure the oscillation signal. This paper describes the experimental setup, the results of the first measurement campaign as well as giving an outlook on the future potential of the experiment.

Research and Development for a Gadolinium Doped Water Cherenkov Detector

The proposed introduction of a soluble gadolinium (Gd) compound into water Cherenkov detectors can result in a high efficiency for the detection of free neutrons capturing on the Gd. The delayed 8 MeV gamma cascades produced by these captures, in coincidence with a prompt positron signal, serve to uniquely identify electron antineutrinos interacting via inverse beta decay. Such coincidence detection can reduce backgrounds, allowing a large Gd-enhanced water Cherenkov detector to make the first observation of supernova relic neutrinos and high precision measurements of Japan's reactor antineutrino flux, while still allowing for all current physics studies to be continued. Now, a dedicated Gd test facility is operating in the Kamioka Mine. This new facility houses everything needed to successfully operate a Gd doped water Cherenkov detector. Successful running of this facility will demonstrate that adding Gd salt to SK is both safe for the detector and is capable of delivering the expected physics benefits

Quest for Direct Detection of Gravitational Waves and Large-scale Cryogenic Gravitational wave Telescope (LCGT) Project in Japan

The quest of direct detection of gravitational waves (GWs) has reached the most interesting stage. During GW observation using LIGO and partially VIRGO and GEO600 for three years, no GW events were observed within a ∼15 Mpc radius from the Earth. To detect several GW events per year, enhancement of strain sensitivity, about ten times as high as for these GW detectors, is in progress. In Japan, Large-scale Cryogenic Gravitational wave Telescope (LCGT) project has also started in 2010 to detect GWs and to form a GW detection network with other GW detectors. LCGT will be constructed at the Kamioka mine, Hida-city, Gifu-prefecture. It is located about 200 meters under the ground surface for stable operation. LCGT is also designed to utilize cryogenic mirrors and cryogenic mirror suspension wires to reduce thermal noises and to reach the quantum noise limiting sensitivity of 10−22 in rms strain.

Experimental Demonstration of Cryogenic Mirror Technique

The thermal noise of mirrors in laser interferometric gravitational wave (GW) detectors is inevitable, fundamental noise and is crucial to whether a sufficiently high sensitivity to detect GWs is reached. The cryogenic mirror technique is one method to reduce the thermal noise. Japanese GW collaboration started in a study of the cryogenic mirror technique in 1997 and continues now through the Cryogenic Laser Interferometer Observatory (CLIO) project, which started in 2002. The CLIO interferometer was completed in an underground site of the Kamioka mine in 2006 as the first cryogenic interferometer for GW detection. We investigated and reduced noise of the CLIO interferometer. The cryogenic technique will be adopted for the Large-scale Cryogenic Gravitational Wave Telescope (LCGT) project, which started in 2010. This article describes the development of the CLIO interferometer and a plan for macroscopic quantum measurement using the CLIO interferometer.

Developments of Cryogenic Laser Interferometer Observatory (CLIO) and Local Suspension Point Interferometer (LSPI) in Kamioka

The Cryogenic Laser Interferometer Observatory (CLIO) is a laser interferometric gravitational wave (GW) detector. CLIO is a prototype of the Large-Scale Cryogenic Gravitational Wave Telescope (LCGT). Both CLIO and LCGT use the same cryogenic mirror technique as well as the underground site of Kamioka mine. The cryogenic mirror technique is a method to reduce thermal noises that are fundamental in GW detectors. The most important purpose of CLIO is to demonstrate sensitivity improvement by using the cryogenic mirror technique. During the operation of CLIO with cryogenic mirrors, several unique behaviors in the interferometer systems were found. One of the serious issues that we found was low effectiveness of the magnet damping system for a mirror suspension system at cryogenic temperatures. Thus, we have developed a new damping system, the Local Suspension Point Interferometer (LSPI). In this article, we give a brief introduction to CLIO and recent results of the LSPI experiments in CLIO.

Thermal-noise-limited underground interferometer CLIO

We report on the current status of CLIO (Cryogenic Laser Interferometer Observatory), which is a prototype interferometer for LCGT (large scale cryogenic gravitational-wave telescope). LCGT is a Japanese next-generation interferometric gravitational-wave detector featuring the use of cryogenic mirrors and a quiet underground site. The main purpose of CLIO is to demonstrate a reduction of the mirror thermal noise by cooling the sapphire mirrors. CLIO is located in an underground site of the Kamioka mine, 1000 m deep from the mountain top, to verify its advantages. After a few years of commissioning work, we have achieved a thermal-noise-limited sensitivity at room temperature. One of the main results of noise hunting was the elimination of thermal noise caused by a conductive coil holder coupled with a pendulum through magnets.

"Compositional zoning and ""chalcopyrite disease"" in sphalerite contained in the Pb-Zn-quartzcalcite ore from the Mozumi deposit of the Kamioka mine, Gifu Prefecture"

"Compositional zoning and ""chalcopyrite disease"" in sphalerite contained in the Pb-Zn-quartzcalcite ore from the Mozumi deposit of the Kamioka mine, Gifu Prefecture"

Disseminated type mineralization in the Tochibora ore deposits, Kamioka mine, Gifu prefecture

Disseminated type mineralization in the Tochibora ore deposits, Kamioka mine, Gifu prefecture

The Zonal Distribution of Lead and Zinc in the Mozumi Mining Area, Kamioka Mine

The Zonal Distribution of Lead and Zinc in the Mozumi Mining Area, Kamioka Mine

Geochemical investigation on a quartz porphyry dyke of the Kamioka Mine, central Japan.

Geochemical investigation on a quartz porphyry dyke of the Kamioka Mine, central Japan.