| Project/Area Number |
06640542
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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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 | The University of Tokyo |
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Principal Investigator |
GELLER Robert J The University of Tokyo Graduate School of Science Associate Professor, 大学院・理学系研究科, 助教授 (40170154)
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| Project Period (FY) |
1994 – 1995
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| Project Status |
Completed (Fiscal Year 1995)
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| Budget Amount *help |
¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1995: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1994: ¥1,400,000 (Direct Cost: ¥1,400,000)
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| Keywords | Earth structure / inversion / synthetic seismograms / numerical computation |
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| Research Abstract |
The purpose of this research project is inverting 3-D earth structure with high accuracy and high resolution using digital seismic waveforms. We have developed an efficient method (Direct Solution Method) which computes synthetic seismograms and their partial derivatives efficiently and a new inverse algorithm. In this research project, we have planed to invert 3-D earth structure using broadband seismic waveforms using these research results. However to invert earth structure with high accuracy, we have developed more accurate and efficient computational methods and softwares. By the research results of this project, the accuracy an the efficiency of computation of synthetic seismograms are greatly improved.
We will list chief research results below.
1.We have computed 4-5000s highly accurate DSM synthetic seismograms using the Direct Solution Method. We showed that we can compute highly accurate synthetics if we use DSM.
2.We have derived a general criterion which should be satisfied by numerically accurate op erators (modified operators), and derived DSM modified operators satisfying this criterion for arbitrarily heterogeneous media without increasing their bandwidth.
3.We have derived modified operators for spherical coordinate problems which will be used for inversions. We have developed softwares using these modified operators for sphericall symmetric and 3-D heterogeneous earth structure. By these results, we came to be able to compute highly accurate 20-5000s P-SV synthetic seismograms in 10 minutes (on SPARC 20). We came to be able to compute highly accurate synthetics for 3-D heterogeneous structure.
4.We have developed theory and softwares which uses analytical solutions as a trial function which are used for expansion of the displacement field.
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