1986 Fiscal Year Final Research Report Summary
Studies on the anisotropy of the upper mantle, seismological and material science approaches
| Project/Area Number |
59420013
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| Research Category |
Grant-in-Aid for General Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Research Field |
固体地球物理学
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| Research Institution | University of Tokyo |
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Principal Investigator |
KUMAZAWA M. Geophys,Inst., Univ. of Tokyo, Professor, 理学部, 教授 (60022571)
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| Co-Investigator(Kenkyū-buntansha) |
MATSUI T. Geophys. Inst., Univ. of Tokyo, Res.Ass., 理学部・地球物理(固体地球), 助手 (80114643)
KURITA K Geophys. Inst., Univ. of Tokyo, Res.Ass., 理学部・地球物理(固体地球), 助手 (00111451)
GELLER R. Geophys, Inst., Univ. of Tokyo, Ass. Prof., 理学部・地球物理(地震学), 助教授 (40170154)
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| Project Period (FY) |
1984 – 1986
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| Keywords | anisotropy / upper mantle / prefened orientation / seismology / 流動 / 部分熔融 |
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| Research Abstract |
The main aim of the present study was to obtain an overall understanding of seismic anisotropy, and of its relation to mantle dynamics. The study consisted of three related parts.
(1) We studied the effect of anisotropy on the earth's free oscillations and surface waves. The matrix elements for an anisotropic, laterally heterogeneous earth model were obtained in closed form. Asymptotic results were obtained for surface waves. These results can be applied in future computations.
(2) The generation of seismic anisotropy was studied from the viewpoint of material science. A gas pressure device to conduct rock deformation experiments at 5kbar and to 1450゜C with very low shear stress ( <wave> lbar). This device incorporates several new experimental techniques: the final deformation test has not yet been made.
Partially molten lherzolite has been experimentally stressed at 40kbar and 1530゜C. by means of an available solid apparatus. Particular oriented alignment of the liquid phase was observed. demonstrating the importance of such experiments.
(3) Numerical modeling of mantle convection. with an overlying cold lithosphere. was carried out using a supercomputer. The thermal coupling between the lithosphere and mantle involved both internal fractionation and material flow. Such modeling can provide constraints for laterally heterogeneous. anisotropic models that can be used as the starting models for inversion of seismic data.
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