1999 Fiscal Year Annual Research Report

海半球ネットワーク:地球内部を覗く新しい目

Research Project

Project/Area Number	09NP1101
Research Institution	The University of Tokyo
Principal Investigator	深尾良夫東京大学, 地震研究所, 教授 (10022708)
Co-Investigator(Kenkyū-buntansha)	浜野洋三東京大学, 大学院・理学系研究科, 教授 (90011709) 金沢敏彦東京大学, 地震研究所, 教授 (30114698) 山田功夫名古屋大学, 大学院・理学研究科, 教授 (60022670) 笠原稔北海道大学, 大学院・理学研究科, 教授 (40001846) 玉木賢策東京大学, 海洋研究所, 教授 (50188421)
Keywords	広帯域地震観測 / 観測システム / 海底長期観測 / GPS観測 / ポセイドン計画 / プレート運動 / マントル・コア / 西太平洋
Research Abstract	1 総括班 (1)総括班会議の年2回の開催 (2)総括班事務局においてニュースレターの発行、ホームページによる情報公開と情報交換 (3)国際シンポジウム「GPSの地球科学への応用」を10月18日-22日筑波国際会議場にて共催 (4)「フィリピン海-中国大陸横断」長期臨時観測計画の実施の総括 (5)第3回[海半球ネットワーク]シンポジウムを6月8日に開催(地球惑星科学関連学会1999年合同学会共通セッション(38報告) 2 海洋島観測班(1班) (1)南鳥島(日本)観測点の改修:ポセイドン初期の観測点であったが、これを標準型のシステムに改修した。 (2)ハノイ(ベトナム)観測点の設置:STS-2地震計と森田式記録計による観測を開始した。 (3)ロシア極東地域・南アジア地域におけるGPS観測を継続して行った。 (4)海洋島(地震、GPS)観測点の保守点検を実施した。 (5)中国大陸における広帯域地震観測を開始した。 3 海洋底観測班(2班) (1)海底掘削孔利用の最初の高性能地震観測点(JT-1およびJT-2)を三陸海溝陸側斜面に設置した。 (2)海底設置型広帯域地震計をJT-2観測点のすぐ近く及び北西海盆のWP-2地点に設置した。 (3)上記観測記録の比較から掘削孔利用の有効性を実証した。 (4)フィリピン海-中国大陸横断観測の一環として稍広帯域地震計アレー(15観測点)と電磁気観測アレー(6観測点)をフィリピン海底に展開した。 4 システム開発班(3班) (1)海底8成分電磁気観測所を北西太平洋に設置した。 (2)海洋島観測では、ワンカヨ、クリスマス島、ポンペイに引き続き長春、トンガに観測点を設置した。 (3)海底ケーブルによる電場変動観測は継続して実施。 (4)オーストラリア、インドネシアに引き続きスピッツペルゲンに超伝導重力計を設置した。 (5)1年以上の長期観測に耐える高性能海底地震計をさらに製作し、一部は観測実施中。 (6)超音波による海底地殻変動観測装置を製作し、長期観測を準備中。 (7)海底熱流量計を改良して、間隙圧も同時に測定できる装置を開発した。 5 データ処理解析班(4班) (1)海半球海洋島地震観測網データセンターを更に整備し、他データセンターとのリンクを行った。 (2)地震波形の直接インバージョンによる3次元地球構造の決定のアルゴリズムを作成し実際に応用した。 (3)西太平洋プレート境界の変動およびマイクロプレート運動を検出した。 (4)非球対称電気伝導度分布推定の試みを開始した。 (5)広帯域地震波形を解析し、マントル構造およびコアマントル境界の構造を解明した。 (6)常時自由振動に年周変化のあることを明らかにした。

Research Products

(32 results)

All Other

All Publications (32 results)

[Publications] Shimizu,H.,and H.Utada: "Ocean Hemisphere Geomagnetic Network : its instrumental design and perspective for long-term geomagnetic observations in the Pacific"Earth Planets Space. 51. 917-932 (1999)
[Publications] 末廣潔: "深海地球ドリリング計画について"第15回海洋工学シンポジウム. 285-288 (2000)
[Publications] Suyehiro,K.,Sacks,S.,Acton,G.D., et al.: "Western Pacific Geophysical Observatories, ODP Leg 186 Scientific Prospectus"ODP/TAMU. 50 (1999)
[Publications] Suyehiro,K.,Sacks,S.,and Leg 186 Scientific Party: "Leg 186 Summary"MARGINS Newsletter. 4. 11-12 (1999)
[Publications] Suyehiro,K.,Sacks,S.,Acton,G.D., et al.: "Western Pacific Geophysical Observatories, ODP Leg 186 Prelim.Rept."ODP/TAMU. 64 (1999)
[Publications] Fujimoto,H.: "Long-term ocean bottom pressure measurement and acoustic ranging across the spreading axis of the Southern East Pacific Rise. (in Japanese with English abstract)"JAMSTEC J.Deep Sea Res.. 14. 35-42 (1999)
[Publications] Fujimoto,H.,and M.Mochizuki: "Monitoring of the spreading activity of the mid-ocean ridge with seafloor acoustic ranging and pressure measurement"Kalyo Monthly, Spec.. 19. 42-48 (1999)
[Publications] Honda,R.,and K.Yomogida: "Synthetic seismograms near a finite fault system"J.Fac.Sci.Hokkaido Univ.. Ser.VII,11. 611-632 (1999)
[Publications] Yoshizawa,K.,K.Yomogida and S.Tsuboi: "Resolving power of surface-wave polarization data for higher-order heterogeneities"Geophys.J.Int.. 138. 205-220 (1999)
[Publications] Zhao Y.and K.Takano: "An Artificial Neural Network Approach for Broadband Seismic Phase picking"Bull.Seism.Soc.Am.. 89. 670-680 (1999)
[Publications] Hara,T. & Gellar,R.J.: "Simultaneous waveform inversion for 3-D Earth structure and earthquake souce parametars considering a wide range of modal coupling"Geopphys.J.Int.,. (submitted). (2000)
[Publications] Takeuchi,N. & Gellar,R.J.: "Optimally Accurate Second Order Time-Domain Finite Difference Scheme for Computing Synthetic Seismograms in 2-D and 3-D Media"Phys.Earth Planet.Int.,. (in press). (2000)
[Publications] Takeuchi,N..Gellar,R.J. & Cummins,P.R.: "Complete synthetic seismograms for 3-D hetrogeneous Earth models computed using modified DSM operators and their applicability to inversion for Earth structure"Phys.Earth Planet.Int.. (in press). (2000)
[Publications] Kimata F.,S.Kariya,M.Fujita,K.Matsumoto,T.Tabei,J.Segawa,A.Yamada: "Estimated pressure source in Kozu Island volcano, southern Central Japan, with GPS measurements"EPS. (submitting). (2000)
[Publications] Takahashi H.,M.Kasahara,F.Kimata,S.Miura,T.Seno,T.Kato,K.Heki,N.Vasilenko,A.Ivashchenko,V.Levin,V.Batiarov,E.Gordeev,F.Korchagin and M.: "Velocity field of around the Sea of Okhotsk and Sea of Japan Regions determined from a continuous GPS network data"Geophys.Res.Lett.. 26. 2533-2537 (1999)
[Publications] Ozawa,T.,T.Tabei and S.Miyazaki: "Interplate coupling along the Nankai Trough off southwest Japan derived from GPS measurements"Geophysical Research Letters. 26,No.7. 927-930 (1999)
[Publications] Widiyantoro,S.,A.Gorvatov,B.L.N.Kennet and Y.Fukao: "Improving global shear-wave travel-time tomography using three dimensional ray tracing and iterative inversion"Geophys.J.Int.. (in press). (2000)
[Publications] A.Gorbatov,S.Widiyantoro,Y.Fukao,and E.Gordeev: "Signature of remnant slabs in the North Pacific from P-wave tomography"Geophys.J.Int.. (in press). (2000)
[Publications] Nishida,K.,N.Kobayashi and Y.Fukao: "Harmoney of the hum between the solid Earth and atmosphere and its annual variation"Science. (in press). (2000)
[Publications] Nawa,K.,N.Suda,Y.Fukao,T.Sato,Y.Tamura,K.Shibuya,H.McQueen,H.Virtanen and J.: "Incessant excitation of the Earth's free oscillations : global comparison of superconducting gravimeter records"Phys.Earth Planet.Inter.. (in press). (2000)
[Publications] Tanimoto,T.: "Excitation of normal modes by atmospheric turbulence : Source of long period seismic noise"Geophys.J.Int.. 136. 395-402 (1999)
[Publications] Yanagisawa,T.and Y.Hamano: ""Skewness" of S-wave velocity in the mantle"Geophys.Res.Lett.. 26. 791-794 (1999)
[Publications] S.Tsuboi,P.M.Whitmore,T.J.Sokolowski,: "Application of Mwp to deep and teleseismic earthquakes"Bulletin of the Seismological Society of America. 89,No.5. 1345-1351 (1999)
[Publications] El-Fiky,G.S.,and T.Kato: "Continuous distribution of the horizontal strain in the Tohoku district, Japan, predicted by least-squares collocation"Geodynamics. 27. 213-236 (1999)
[Publications] El-Fiky,G.S.,and T.Kato: "Interplate coupling in the Tohoku district, Japan, deduced from geodetic data inversion"J.Geophys.Res.. 104,B9. 20361-20377 (1999)
[Publications] Yoshiwara,A.and Y.Hamano: "Intensity of the earth's magnetic field in late Archean obtained from diabase dikes of the Slave Province"Phys.Earth Planet.Int.,117,295-307,2000.. 117. 295-307 (2000)
[Publications] Nakanishi,M.,W.W.Sager,and A.Klaus: "Magnetic Lineations within Shatsky Rise, Northwest Pacific Ocean : Implications for Hot Spot-Triple Junction Interaction and Oceanic Plateau Formation"J.Geophys.Res.. 104. 7539-7556 (1999)
[Publications] Evans,L.,P.Tarits,A.D.Chave,A.White,G.Heinson,J.H.Filloux,H.Toh,N.Seama,H.Utada,J.R.Booker,and M.J.Unsworth: "Asymmetric Electrical Structure in the Mantle Beneath the East Pacific Rise at 17°S"Science. 286,5440. 752-756 (1999)
[Publications] Yamaguchi,S.,Y.Kocayashi,N.Oshiman,K.Tanimoto,H.Murakami,I.Shiozaki,M.Uyeshima,H.Utada,and N.Sumitomo Hideki Shimamura: "Preliminary report on regional resistivity variation inferred from the Network-MT investigation in the Shikoku district, southwestern Japan"Earth Planets Space. 51. 193-203 (1999)
[Publications] Toh,H.,A.Schultz and M.Uyeshima: "Biconjugate gradient solution of a spherical 3D EM forward solver using a staggered-grid integral formulation and its acceleration over multi-frequencies"Proc.2nd Int.Symp.3DEM, Univ.Utah. 205-208 (1999)
[Publications] Sager,W.W.,J.Kim,A.Klaus,M.Nakanishi,and L.M.Khankishieva: "Bathymetry of Shatsky Rise, northwestern Pacific Ocean : Implications for ocean plateau development at a triple junction"J.Geophys.Res.. 104. 7557-7576 (1999)
[Publications] 望月公廣,荒木英一郎,米島慎二,山本富士夫,徳山英一,末廣潔,平朝彦: "海台の地殻構造と沈み込み帯での運命"月刊地球. 号外No.23. 149-159 (1999)

1999 Fiscal Year Annual Research Report

海半球ネットワーク:地球内部を覗く新しい目

Principal Investigator

深尾 良夫 東京大学, 地震研究所, 教授 (10022708)

Research Products

[Publications] Shimizu,H.,and H.Utada: "Ocean Hemisphere Geomagnetic Network : its instrumental design and perspective for long-term geomagnetic observations in the Pacific"Earth Planets Space. 51. 917-932 (1999)

[Publications] 末廣潔: "深海地球ドリリング計画について"第15回海洋工学シンポジウム. 285-288 (2000)

[Publications] Suyehiro,K.,Sacks,S.,Acton,G.D., et al.: "Western Pacific Geophysical Observatories, ODP Leg 186 Scientific Prospectus"ODP/TAMU. 50 (1999)

[Publications] Suyehiro,K.,Sacks,S.,and Leg 186 Scientific Party: "Leg 186 Summary"MARGINS Newsletter. 4. 11-12 (1999)

[Publications] Suyehiro,K.,Sacks,S.,Acton,G.D., et al.: "Western Pacific Geophysical Observatories, ODP Leg 186 Prelim.Rept."ODP/TAMU. 64 (1999)

[Publications] Fujimoto,H.: "Long-term ocean bottom pressure measurement and acoustic ranging across the spreading axis of the Southern East Pacific Rise. (in Japanese with English abstract)"JAMSTEC J.Deep Sea Res.. 14. 35-42 (1999)

[Publications] Fujimoto,H.,and M.Mochizuki: "Monitoring of the spreading activity of the mid-ocean ridge with seafloor acoustic ranging and pressure measurement"Kalyo Monthly, Spec.. 19. 42-48 (1999)

[Publications] Honda,R.,and K.Yomogida: "Synthetic seismograms near a finite fault system"J.Fac.Sci.Hokkaido Univ.. Ser.VII,11. 611-632 (1999)

[Publications] Yoshizawa,K.,K.Yomogida and S.Tsuboi: "Resolving power of surface-wave polarization data for higher-order heterogeneities"Geophys.J.Int.. 138. 205-220 (1999)

[Publications] Zhao Y.and K.Takano: "An Artificial Neural Network Approach for Broadband Seismic Phase picking"Bull.Seism.Soc.Am.. 89. 670-680 (1999)

[Publications] Hara,T. & Gellar,R.J.: "Simultaneous waveform inversion for 3-D Earth structure and earthquake souce parametars considering a wide range of modal coupling"Geopphys.J.Int.,. (submitted). (2000)

[Publications] Takeuchi,N. & Gellar,R.J.: "Optimally Accurate Second Order Time-Domain Finite Difference Scheme for Computing Synthetic Seismograms in 2-D and 3-D Media"Phys.Earth Planet.Int.,. (in press). (2000)

[Publications] Takeuchi,N..Gellar,R.J. & Cummins,P.R.: "Complete synthetic seismograms for 3-D hetrogeneous Earth models computed using modified DSM operators and their applicability to inversion for Earth structure"Phys.Earth Planet.Int.. (in press). (2000)

[Publications] Kimata F.,S.Kariya,M.Fujita,K.Matsumoto,T.Tabei,J.Segawa,A.Yamada: "Estimated pressure source in Kozu Island volcano, southern Central Japan, with GPS measurements"EPS. (submitting). (2000)

[Publications] Ozawa,T.,T.Tabei and S.Miyazaki: "Interplate coupling along the Nankai Trough off southwest Japan derived from GPS measurements"Geophysical Research Letters. 26,No.7. 927-930 (1999)

[Publications] Widiyantoro,S.,A.Gorvatov,B.L.N.Kennet and Y.Fukao: "Improving global shear-wave travel-time tomography using three dimensional ray tracing and iterative inversion"Geophys.J.Int.. (in press). (2000)

[Publications] A.Gorbatov,S.Widiyantoro,Y.Fukao,and E.Gordeev: "Signature of remnant slabs in the North Pacific from P-wave tomography"Geophys.J.Int.. (in press). (2000)

[Publications] Nishida,K.,N.Kobayashi and Y.Fukao: "Harmoney of the hum between the solid Earth and atmosphere and its annual variation"Science. (in press). (2000)

[Publications] Nawa,K.,N.Suda,Y.Fukao,T.Sato,Y.Tamura,K.Shibuya,H.McQueen,H.Virtanen and J.: "Incessant excitation of the Earth's free oscillations : global comparison of superconducting gravimeter records"Phys.Earth Planet.Inter.. (in press). (2000)

[Publications] Tanimoto,T.: "Excitation of normal modes by atmospheric turbulence : Source of long period seismic noise"Geophys.J.Int.. 136. 395-402 (1999)

[Publications] Yanagisawa,T.and Y.Hamano: ""Skewness" of S-wave velocity in the mantle"Geophys.Res.Lett.. 26. 791-794 (1999)

[Publications] S.Tsuboi,P.M.Whitmore,T.J.Sokolowski,: "Application of Mwp to deep and teleseismic earthquakes"Bulletin of the Seismological Society of America. 89,No.5. 1345-1351 (1999)

[Publications] El-Fiky,G.S.,and T.Kato: "Continuous distribution of the horizontal strain in the Tohoku district, Japan, predicted by least-squares collocation"Geodynamics. 27. 213-236 (1999)

[Publications] El-Fiky,G.S.,and T.Kato: "Interplate coupling in the Tohoku district, Japan, deduced from geodetic data inversion"J.Geophys.Res.. 104,B9. 20361-20377 (1999)

[Publications] Yoshiwara,A.and Y.Hamano: "Intensity of the earth's magnetic field in late Archean obtained from diabase dikes of the Slave Province"Phys.Earth Planet.Int.,117,295-307,2000.. 117. 295-307 (2000)

[Publications] Nakanishi,M.,W.W.Sager,and A.Klaus: "Magnetic Lineations within Shatsky Rise, Northwest Pacific Ocean : Implications for Hot Spot-Triple Junction Interaction and Oceanic Plateau Formation"J.Geophys.Res.. 104. 7539-7556 (1999)

[Publications] Evans,L.,P.Tarits,A.D.Chave,A.White,G.Heinson,J.H.Filloux,H.Toh,N.Seama,H.Utada,J.R.Booker,and M.J.Unsworth: "Asymmetric Electrical Structure in the Mantle Beneath the East Pacific Rise at 17°S"Science. 286,5440. 752-756 (1999)

[Publications] Toh,H.,A.Schultz and M.Uyeshima: "Biconjugate gradient solution of a spherical 3D EM forward solver using a staggered-grid integral formulation and its acceleration over multi-frequencies"Proc.2nd Int.Symp.3DEM, Univ.Utah. 205-208 (1999)

[Publications] Sager,W.W.,J.Kim,A.Klaus,M.Nakanishi,and L.M.Khankishieva: "Bathymetry of Shatsky Rise, northwestern Pacific Ocean : Implications for ocean plateau development at a triple junction"J.Geophys.Res.. 104. 7557-7576 (1999)

[Publications] 望月公廣,荒木英一郎,米島慎二,山本富士夫,徳山英一,末廣潔,平朝彦: "海台の地殻構造と沈み込み帯での運命"月刊地球. 号外No.23. 149-159 (1999)

深尾良夫東京大学, 地震研究所, 教授 (10022708)