• Search Research Projects
  • Search Researchers
  • How to Use
  1. Back to previous page

Determination of the structure of the Earth's core using normal mode of the Earth

Research Project

Project/Area Number 13640426
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field 固体地球物理学
Research InstitutionJapan Marine Science and Technology Center (2002)
Yokohama City University (2001)

Principal Investigator

TSUBOI Seiji  Japan Marine Science and Technology Center, Institute of Frontier Research on Earth Evolution, Group leader, 固体地球統合フロンティア研究システム, グループリーダー (90183871)

Co-Investigator(Kenkyū-buntansha) SAITO Masanori  Yokohama City University, Graduate School of Integrated Science, Professor, 大学院・総合理学研究科, 教授 (10011553)
Project Period (FY) 2001 – 2002
Project Status Completed (Fiscal Year 2002)
Budget Amount *help
¥3,400,000 (Direct Cost: ¥3,400,000)
Fiscal Year 2002: ¥1,200,000 (Direct Cost: ¥1,200,000)
Fiscal Year 2001: ¥2,200,000 (Direct Cost: ¥2,200,000)
KeywordsNormal modes of the Earth / Earth's core / 核の構造 / 数値計算
Research Abstract

We calculate normal modes for the Earth model, which has a slight rigidity layer at the base of the liquid outer core. We show that such a layer with thickness about 40 km and the shear wave velocity of 0.017 km/sec can produce a normal mode, which has a close eigenfrequency to that of liquid core model, without affecting fundamental modes and most of the higher modes. Our results indicate that the thin finite rigidity layer at the base of the outer core might explain the anomalous splitting of the Earth's normal modes, which has not been fully explained by the anisotropy in the inner core. We also have shown that we may interpret that the soft core mode, which appeared at _3S_2 , may arise as a result of coupling between those trapped modes within thin finite rigidity layer at the bottom of the oute core and the ordinary normal modes. For a preparation of confirmation of the existence of this thin finite rigidity layer at the bottom of the outer core by using body wave, we have set up a computer program to calculate synthetic seismic waveform for fully three dimensional Earth model. We use a spectral element method on the Earth Simulator. We use 243 nodes(1944 CPUs) of the Earth simulator and calculate synthetic seismic wave which is accurate up to 5 seconds. This synthetic waveforms consider all of the heterogeneity inside the Earth and its effect to the seismic wave propagation. Thus we should be able to use these waveforms to study fine structure of Earth's core.

Report

(3 results)
  • 2002 Annual Research Report   Final Research Report Summary
  • 2001 Annual Research Report
  • Research Products

    (6 results)

All Other

All Publications (6 results)

  • [Publications] Tsuboi, S., Saito, M.: "Existence of finite rigidity layer at the base of the Earth's liquid outer core inferred from anomalous splitting of normal modes"Earth Planets Space. Vol.54. 167-171 (2002)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2002 Final Research Report Summary
  • [Publications] Tsuboi, S., Saito, M.: "Physical significance of soft core splitting modes of the Earth"IFREE Report. Vol.1. 317-320 (2002)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2002 Final Research Report Summary
  • [Publications] Tsuboi, S & Saito, M.: "Existence of finite rigidity layer at the base of the Earth's liquid outer core inferred from anomalous splitting of normal modes"Earth Planets Space. Vol.54, No.2. 167-171 (2002)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2002 Final Research Report Summary
  • [Publications] Tsuboi, S & Saito, M.: "Physical significance of soft core splitting modes of the Earth"Frontier Research on Earth Evolution. Vol.1, IFREE Report for 2001-2002. 317-320 (2002)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2002 Final Research Report Summary
  • [Publications] Tsuboi, S., Saito, M.: "Physical significance of soft core splitting modes of the Earth"IFREE Report. Vol.1. 317-320 (2002)

    • Related Report
      2002 Annual Research Report
  • [Publications] Tsuboi, S., Saito, M.: "Existence of finite rigidity layer at the base of the Eavth's liquid outer core inferved from anoinalous splitting pf norid malt"Earth Planets Space. 54・2. 167-171 (2002)

    • Related Report
      2001 Annual Research Report

URL: 

Published: 2001-04-01   Modified: 2016-04-21  

Information User Guide FAQ News Terms of Use Attribution of KAKENHI

Powered by NII kakenhi