不均質構造による散乱と短周期地震波エンベロープの研究

2009 Fiscal Year Annual Research Report

• Project/Area Number: 21540426
• Research Institution: Tohoku University
• Principal Investigator: 佐藤 春夫 Tohoku University, 大学院・理学研究科, 教授 (80225987)
• Keywords: 地震波 / 不均質構造 / 散乱 / 島弧 / 地殻 / リソスフェア / マントル / 波動

Research Abstract

本研究は,固体地球の不均質構造における地震波動伝播の数理的モデルの構築と,観測される短周期地震波エンベロープの解析に基づく不均質構造の解明を目的とする.今年度の研究成果を以下にまとめる.
A.ランダム不均質構造における地震波動伝播の数理的モデルの構築
マルコフ近似法を用いて,ランダム不均質構造における短周期波形のエンベロープの統計的導出に成功した(Emoto et al.2010).ノイズ相互相関関数から不均質構造におけるグリーン関数を導出する方法について,ボルン近似法に基づく証明に成功した(Sato,2009,2010).
B.短周期地震波エンベロープの解析に基づく不均質構造の解明
微小地震のS波の拡大現象を解析し不均質構造のスペクトルを推定するインバージョン法を構築し,東北地方の不均質構造を明らかにした(Takahashi et al.2009).多重等方散乱モデルに基づいてHi-netによる地震波形データを解析し,日本全土の散乱減衰と内部減衰の分布図を作成した(Carcole and Sato, 2010).PS変換散乱の多重等方散乱モデルに基づいて浅間山における爆破地震動を解析し,活火山におけるS波の平均自由行程が1kmと短いことを明らかにした.(Yamamoto and Sato, 2010)

Research Products

• [Journal Article] Retrieval of Green's function having coda waves from the cross-correlation function in a scattering medium illuminated by a randomly homogeneous distribution of noise sources on the basis of the first order Born approximation (2010)
  • Author(s): Sato, H.
  • Journal Title: Geophys.J.Int. 180 Pages: 759-764
  • Peer Reviewed
• [Journal Article] Spatial distribution of scattering loss and intrinsic absorption of short-□period S-waves in the lithosphere of Japan on the basis of the Multiple□Lapse Time Window Analysis of Hi-net data (2010)
  • Author(s): Carcole, E., Sato, H.
  • Journal Title: Geophys.J.Int. 180 Pages: 268-290
  • Peer Reviewed
• [Journal Article] Multiple scattering and mode conversion revealed by an active seismic experiment at Asama volcano, Japan (2010)
  • Author(s): Yamamoto, M., H.Sato
  • Journal Title: J.Geophys.Res. (未定, 印刷中)
  • Peer Reviewed
• [Journal Article] Synthesis of vector-wave envelopes on the free surface of a random medium for the vertical incidence of a plane wavelet based on the Markov approximation (2010)
  • Author(s): Emoto, K., H.Sato, T.Nishimura
  • Journal Title: J.Geophys.Res. (未定, 印刷中)
  • Peer Reviewed
• [Journal Article] Retrieval of Green's function having coda from the cross-correlation function in a scattering medium illuminated by surrounding noise sources on the basis of the first order Born approximation (2009)
  • Author(s): Sato, H.
  • Journal Title: Geophys.J.Int. 113 Pages: 408-412
  • Peer Reviewed
• [Journal Article] Green function retrieval from the CCF of coda waves in a scattering medium (2009)
  • Author(s): Sato, H.
  • Journal Title: Geophys.J.Int. 179 Pages: 1580-1583
  • Peer Reviewed
• [Journal Article] Tomographic inversion of the peak delay times to reveal random velocity fluctuations in the lithosphere : method and application to northeastern Japan (2009)
  • Author(s): Takahashi, T., Sato, H., Nishimura, T., Obara, K.
  • Journal Title: Geophys.J.Int. 178 Pages: 1437-1455
  • Peer Reviewed
• [Journal Article] A performance study of a laser Doppler vibrometer for measuring waveforms from piezoelectric transducers (2009)
  • Author(s): Fukushima, Y., Nishizawa, O., Sato, H.
  • Journal Title: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency 56 Pages: 1442-1450
  • Peer Reviewed
• [Journal Article] Time-lapse changes of seismic velocity in the shallow ground caused by strong ground motion shock of the 2000 Western-Tottori Earthquake, Japan, as revealed from coda deconvolution analysis (2009)
  • Author(s): Sawazaki, K., Sato.H., Nakahara, H., Nishimura, T
  • Journal Title: Bull.Seismol.Soc.Am 99 Pages: 352-366
  • Peer Reviewed
• [Journal Article] Estimation of coda Q in the mantle and characteristics of regional S-wave envelopes (2009)
  • Author(s): Lee, W.S., H.Sato, S.Yun
  • Journal Title: Geosciences Journal 13 Pages: 363-369
  • Peer Reviewed
• [Journal Article] (2009)
  • Author(s): Sato, H.
  • Journal Title: Springer Verlag GmbH(Scattering of seismic waves in the heterogeneous Earth, in "Encyclopedia of Complexity and Systems Science (Ed. R. A. Mayers)"分担執筆) Pages: 7914-7931
• [Remarks]
  • URL: http://zisin.geophys.tohoku.ac.jp/~sato/index.html