Vol.9 No.2 2016

Research paper : Development of rock deformation techniques under high-pressure and high-temperature conditions (Koji MASUDA)−109−Synthesiology - English edition Vol.9 No.2 (2016) AuthorKoji MASUDACompleted the doctoral program in the Department of Earth and Planetary Sciences, Graduate School of Science, Nagoya University, and obtained the degree of Doctor of Science in 1987. Joined the Geological Survey of Japan, Agency of Industrial Science and Technology, Ministry of International Trade and Industry, in 1990. Specialties are geophysics of the Earth’s interior, seismology, and rock mechanics. Conducts research on the role of fluids in earthquake generation mechanisms and physicochemical processes by using the methods of rock mechanics. Deputy Director, Research Institute of Earthquake and Volcano Geology, AIST, since 2014.Discussions with Reviewers1 OverallComment (Chikao Kurimoto, AIST)Japan is positioned in one of the world’s most active belts of crustal movement and thus experiences frequent geological disasters. There is a demand to build a society that is resistant against earthquake disasters, and research on earthquake forecasting is essential. This paper addresses the challenging topic of how rock experiments are used to reproduce geological phenomena that occurred deep underground in the past and to verify an earthquake forecast model. This work integrates advanced technological developments and investigations of geological phenomena to understand the differences in spatial scale, structural conditions, and time between the laboratory and the natural world and presents a clear research scenario, and I think the paper is appropriate for publication in Synthesiology.Comment (Toshimi Shimizu, AIST)This research addresses experimental techniques and methods to accelerate and investigate rock deformation and fracture processes that progress on a thousand-year scale in the natural world. The work has been developed through the introduction and integration of original high-pressure and high-temperature technologies with a compression testing apparatus that has been used for general materials testing. It is extremely interesting that the effectiveness of this method was demonstrated by a laboratory experiment showing the adequacy of the hypothesis that when water is present, fault friction strength weakens over a long period of time. This paper is a case study that contributes social value by constructing a high-precision earthquake forecast model, and I think the content is appropriate for Synthesiology.2 Refinement of the earthquake forecast modelComment (Toshimi Shimizu)As a goal of this study, you mention the construction of a high-precision earthquake forecast model. I understand that the analysis of rock behavior and property changes based on accelerated tests under high temperature and high pressure can be helpful in investigations of earthquake occurrence mechanisms. However, I think that it is rather difficult to understand how the outcomes of this research can directly or indirectly help the general public prepare appropriately for an earthquake disaster. On the other hand, research on forecasting the timing and scale of mega-earthquakes in the future based on surveys of active ancient earthquake studies and problems in announcing study results to society, Synthesiology, 5 (4), 234–242 (2012) (in Japanese) [Synthesiology English edition, 5 (4), 241–250 (2012)].[6]N. Koizumi: Earthquake prediction research based on observation of groundwater— Earthquake forecasting based on crustal deformation estimated from groundwater level change, Synthesiology, 6 (1), 24–33 (2013) (in Japanese) [Synthesiology English edition, 6 (1), 27–37 (2013)].[7]A. Hasegawa, H. Sato and T. Nishimura: Jishingaku (Seismology), Kyoritsu Shuppan (2015) (in Japanese).[8]N. Hirata: Shuto Chokka Jishin (Epicentral Earthquake in Tokyo Metropolitan Area), Iwanami Shoten (2016) (in Japanese).[9]F. Yamashita, E. Fukuyama, K. Mizoguchi, S. Takizawa, S. Xu and H. Kawakata: Scale dependence of rock friction at high work rate, Nature, 528, 254–257 (2015).[10]T. E. Tullis and J. Tullis: Experimental rock deformation techniques, Mineral and Rock Deformation: Laboratory Studies, The Paterson Volume, B. E. Hobbs and H. C. Heard eds, Geophysical Monograph, 36, 297–324 (1986).[11]K. Hoshino: Experimental apparatus of rock deformation under high pressure, Journal of the Japanese Association of Petroleum Technologists, 44 (3), 161–165 (1979) (in Japanese).[12]M. S. Paterson: A high-pressure, high-temperature apparatus for rock deformation, Int. J. Rock Mech. Min. Sci., 7, 517–526 (1970).[13]K. Ujiie, H. Tanaka, T. Saito, A. Tsutsumi, J. Mori, J. Kameda, E. Brodsky, F. Chester, N. Eguchi, S. Toczko, Expedition 343 and 343T Scientists: Low coseismic shear stress on the Tohoku-Oki megathrust determined from laboratory experiments, Science, 342, 1211–1214 (2013).[14]M. S. Paterson: Rock deformation experimentation, The Brittle-Ductile Transition in Rocks, The Heard Volume, A. G. Duba, W. B. Durham, J. W. Handin and H. F. Wang, eds, Geophysical Monograph, 56, 187–194 (1990).[15]S. W. Freiman: Effects of chemical environments on slow crack growth in glasses and ceramics, J. Geophys. Res., 89, 4072–4076 (1984).[16]K. Masuda: Effects of water on rock strength in a brittle regime, J. Struct. Geol., 23, 1635–1657 (2001).[17]K. Masuda, K. Fujimoto and T. Arai: A new gas-medium, high-pressure and high-temperature deformation apparatus at AIST, Japan, Earth Planets Space, 54, 1091–1094 (2002).[18]K. Masuda, T. Arai, K. Fujimoto, M. Takahashi and N. Shigematsu: Effect of water on weakening preceding rupture of laboratory-scale faults: Implications for long-term weakening of crustal faults, Geophys. Res. Lett., 39, L01307, doi:10.1029/2011GL050493 (2012).[19]K. Masuda, K. Iryo and A. Ogura: Internal furnace for the gas-medium high-pressure and high-temperature apparatus at the Geological Survey of Japan/AIST, Japanese Journal of Structural Geology, 49, 73–76 (2006) (in Japanese).


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