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Study on the regionality of earthquake Source spectra

Research Project

Project/Area Number 04640394
Research Category

Grant-in-Aid for General Scientific Research (C)

Allocation TypeSingle-year Grants
Research Field 固体地球物理学
Research InstitutionTOHOKU UNIVERSITY

Principal Investigator

OHTAKE Masakazu  Tohoku Univ. Geophysical Institute, Professor, 理学部, 教授 (60203816)

Co-Investigator(Kenkyū-buntansha) SATO Haruo  Tohoku Univ. Geophysical Institute, Associate Prof., 理学部, 助教授 (80225987)
Project Period (FY) 1992 – 1993
Project Status Completed (Fiscal Year 1993)
Budget Amount *help
¥1,700,000 (Direct Cost: ¥1,700,000)
Fiscal Year 1993: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1992: ¥1,200,000 (Direct Cost: ¥1,200,000)
Keywordsseismic wave / source spectrum / stress drop / attenuation / scattering / site effect / 火山フロント / 地盤の増巾特性 / スペクトル
Research Abstract

For assessing the regionality of earthquake source spectra, we analized waveforms of micro- to small-sized earthquakes ocurring in different regions in Japan. One of the most important results is the finding of systematic difference in stress drop for shallow earthquakes occurring in the aftershock region of the 1984 Naganoken-Seibu earthquake (M=6.8) and in the Asio region where stationary seismic activity is observed. Detailed analysis of waveforms revealed that the ratio of P to S wave attenuation is higher than unity in contrast to past studies. We also revealed that site amplification effect is not negligible even at hard-rock observatiion sites for high-frequency seismic waves. We further attempted to separate the effects of seismic wave dissipation due to intrinsic attenuation and scattering, based on the theoretical formulation of scattering behavior that was done in this study. The theoretical work includes formulation of analitic solutions of the two-dimensional multiple isotropic scattering, and seismogram envelope synthetics including P-S conversions.
The broad-band seismometer that was newly installed by this study is in full operation, and the observation is to be continued. The high quality date from this observation will largely contribute to extend our study to larger earthquakes.

Report

(3 results)
  • 1993 Annual Research Report   Final Research Report Summary
  • 1992 Annual Research Report
  • Research Products

    (19 results)

All Other

All Publications (19 results)

  • [Publications] Ohtake,M.: "Derivation of the three-parameter model of frequency distribution of earthquake magnitude" Tohoku Geophys.J.34. 115-119 (1993)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1993 Final Research Report Summary
  • [Publications] Yoshimoto,K.: "Frequency dependent attenuation of P and S waves in the Kanto area,Japan,based on the coda normalization method" Geophys.J.Int.114. 165-174 (1993)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1993 Final Research Report Summary
  • [Publications] Sato,H.: "Energy transport in one- and two-dimensional scattering media:Analytic solutions of the multiple isotropic scattering media" Geophys.J.Int.112. 141-146 (1993)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1993 Final Research Report Summary
  • [Publications] Sato,H.: "Multiple isotropic scattering model including P-S conversions for the seismogram envelope formation" Geophys.J.Int.(印刷中).

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1993 Final Research Report Summary
  • [Publications] Sato,H.: "Formulation of multiple non-isotropic scattering process in two-dimensional space on the basis of energy transport theory" Geophys.J.Int.(印刷中).

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1993 Final Research Report Summary
  • [Publications] Yoshimoto,K.: "High-frequency site effect of hard rocks at Ashio,central Japan" J.Phys.Earth. 41. 327-335 (1993)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1993 Final Research Report Summary
  • [Publications] Ohtake, M: "Derivation of the three-parameter model of frequency destribution of earthquake magnitude" Tohoku Geophys.J.34. 115-119 (1993)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1993 Final Research Report Summary
  • [Publications] Yosimoto, K., H.Sato and M.Ohtake: "Frequency dependent attenuation of P and S waves in the Kanto area. Japan, based on the coda normalization method" Geophys.J.Int.114. 165-174 (1993)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1993 Final Research Report Summary
  • [Publications] Sato, H.: "Energy transportatin in one- and two- dimensional scattering media : Analytic solutions of the mutiple isotropic scattering model" Geophys.J.Int.112. 141-146 (1993)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1993 Final Research Report Summary
  • [Publications] Sato, H.: "Multiple isotropic scattering model including P-S conversions for the seismogram envelope formation" Geophys.J.Int.(in Press). (1994)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1993 Final Research Report Summary
  • [Publications] Sato, H.: "Formulation of multiple non-isotropic scattering process in two-dimensional space on the basis of energy transport theory" Geophys.J.Int.(in Press). (1994)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1993 Final Research Report Summary
  • [Publications] Yoshimoto, K.H.Sato, S.Kinoshita and M.Ohtake: "High-frequency site effect of hard rocks at Ashio, central Japan" J.Phys.Earth. 41. 327-335 (1994)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1993 Final Research Report Summary
  • [Publications] Yoshimoto,K.,H,Sato and M.Ohtake: "Frequency dependent attenuation of P and S waves in the Kanto area,Japan,based on the coda mormalization method" Geophys.J.Int.114. 165-174 (1993)

    • Related Report
      1993 Annual Research Report
  • [Publications] Ohtake,M.: "Derivation of the three-parameter model of frequency distribution of earthquake magnitude" Tohoku Geophys.J.34. 115-119 (1993)

    • Related Report
      1993 Annual Research Report
  • [Publications] Sato,H.: "Energy transportation in one- and two-dimensional scattering media:Analytic solutions of the multiple isotropic scattering model" Geophys.J.Int.112. 141-146 (1993)

    • Related Report
      1993 Annual Research Report
  • [Publications] Yoshimoto,K.,H.Sato,S.Kinoshita and M.Ohtake: "High-frequency site effect of hard rocks at Ashio,central Japan" J.Phys.Earth. 41. 327-335 (1993)

    • Related Report
      1993 Annual Research Report
  • [Publications] Sato,H.: "Multiple isotropic scattering model including P-S conversions for the seismogram envelope formation" Geophys.J.Int.(印刷中).

    • Related Report
      1993 Annual Research Report
  • [Publications] Fukushima,Y.,et al.: "Measurement of Q^<-1> for S waves in Mudstone at Chikura,Japan:Comparison of incident and reflected phases" Bull.Seismol.Soc.Amer.82. 148-163 (1992)

    • Related Report
      1992 Annual Research Report
  • [Publications] Yoshimoto,K.,et al.: "Frequency dependent attenuation of P and S waves in the Kanto area,Japan,based on the coda normalizaction method" Geophys.J.Internat.110. (1993)

    • Related Report
      1992 Annual Research Report

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Published: 1992-04-01   Modified: 2016-04-21  

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