| Project/Area Number |
14540393
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
固体地球物理学
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| Research Institution | The University of Tokyo |
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Principal Investigator |
GELLER Robert J. The University of Tokyo, Graduate School of Science, Professor, 大学院・理学系研究科, 教授 (40170154)
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| Co-Investigator(Kenkyū-buntansha) |
TAKEUCHI Nozomu The University of Tokyo, Earthquake Research Institute, Research Associate, 地震研究所, 助手 (90313048)
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| Project Period (FY) |
2002 – 2004
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| Project Status |
Completed (Fiscal Year 2004)
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| Budget Amount *help |
¥3,200,000 (Direct Cost: ¥3,200,000)
Fiscal Year 2004: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 2003: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 2002: ¥1,400,000 (Direct Cost: ¥1,400,000)
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| Keywords | Earth structure / Seismic discontinuity / Synthetic seismograms / Direct Solution Method / Optimally accurate operator / Anisotropy / 浅発地震 / 凸凹構造 / angular order |
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| Research Abstract |
The purpose of this research project was to analyze broadband seismic data to determine the fine structure of the Earth's interior., including seismic discontinuities. Progress towards this goal requires accurate and efficient methods for calculating synthetic seismograms and their partial derivatives, and for conducting inversion for seismic structure models. We achieved the following progress in these areas.
Forward calculations : (1)In many previous numerical methods the accuracy of synthetic seismograms seriously degraded if the seismic source was not located exactly at a node of the computational grid. We have developed methods that allow calculations for arbitrarily located seismic sources with the same accuracy as for seismic sources at grid points. (2)The accuracy of many previous finite difference schemes was seriously degraded if lithological discontinuities did not coincide exactly with the computational grid. We developed optimally accurate numerical operators for elements containing inter-node lithological discontinuities.
Inversion : (1)We developed an accurate scheme for a finite perturbation to a lithological discontinuity. (2)In most global studies seismic sources and observatories are not uniformly distributed. We developed a weighting scheme to account for this uneven distribution when carrying out seismic inversion, and applied it to an observed dataset to obtain an unbiased 3-D Earth model.
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