1997 Fiscal Year Final Research Report Summary
Development of fast-operating servo-controlled loading frame for studying earthquake generating processes
| Project/Area Number |
05558046
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| Research Category |
Grant-in-Aid for Developmental Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Natural disaster science
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| Research Institution | The University of Tokyo |
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Principal Investigator |
SHIMAMOTO Toshihiko Earthquake Research Institute, University of Tokyo, Professor, 地震研究所, 教授 (20112170)
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| Co-Investigator(Kenkyū-buntansha) |
NAGAHAMA Hiroyuki Faculty of Science, Yohoku University, Assistant, 助手), 助手 (60237550)
KANAGAWA Kyuichi Faculty of Science, Chiba University, Associate pfofessor, 理学部, 助教授 (40185898)
SHIMIZU Ichiko Graduate School of Science, University of Tokyo, Assistant, 大学院・理学系研究科, 助手 (40211966)
NAKASHIMA Satoru Graduate School of Science, University of Hokkaido, Professor, 大学院・理学研究科, 教授 (80237255)
TORIUMI Mitsuhiro Graduate School of Science, University of Tokyo, Professor, 大学院・理学系研究科, 教授 (10013757)
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| Project Period (FY) |
1993 – 1994
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| Keywords | Servi-controlled machine, / fault / fault rock, / fault model, / Harper-Corn creep, / plate tectonics, / mechanism of earthquake generation, / non-equilibrium thermodynamics |
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| Research Abstract |
The main task of the present research project has been (1) to develope a new fast-response servo-controlled loading system for studying fault constitive properties while controlling unstable fault motion, (2) to establish a realistic fault model through the analyzes of intrafault processes in fault rocks and through high temperature experiments producing the same processes as recognized in deep fault zones, and (3) to perform basic researches on rock rheology and propose rheological models for the lithosphere and plate boundaries. A new servo-controlled testing machine capable of 200Hz cyclic testing under the dynamic loading to 500kN was designed and built during the official period of this project, and the machine can now be used as a high temperature (to 1,000ﾟC) biaxial machine combined with a horizontal press and a furnace that were built with other funds. The machine is extended now as a conventional triaxial testing machine with good capability of permeability measurements and w
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ill open ways for studying constitutive properties of deep faults. Other results are as follows.
(1) Complete transition from brittle, through intermediate, to fully plastic deformation under extreme shear has been studied for halite and halite-calcite mixed shear zones at temperatures increasing linearly with an increase in the normal stress to the fault (as in the case of geothermal gradient). Previous fault models were all denied and a new fault and plate-boundary model was proposed.
(2) Rheological model has revealed unique features of island arc lithosphere and explains tectonics and seismicity of Japanese islands. A new rheological model of subducting plate boundaries was proposed so account for the extream variation of interplate thrust-type earthquakes as revealed by comparative subductology.
(3) Harper-Dorn creep was proposed based on existing experimental data on various materials including minerals. Predictions from power-law creep will be changed substantially if this is the case.
(4) Shimizu's theory of non-equilibrium thermodynamics was extended and applied to intracrystalline diffusion creep. Less
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