A study on a stratified layer in the Earth's liquid core from global seismological data

2008 Fiscal Year Final Research Report

• Project/Area Number: 18340125
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Solid earth and planetary physics
• Research Institution: Japan Agency for Marine-Earth Science and Technology
• Principal Investigator: TANAKA Satoru Japan Agency for Marine-Earth Science and Technology, 地球内部変動研究センター, 主任研究員 (60281961)
• Project Period (FY): 2006 – 2008
• Keywords: 地球流体核 / 外核最上部 / SmKS 波 / P4KP 波 / コア / マントル境界

Research Abstract

外核最上部約100km のP 波速度は,標準モデルから予想されるより最大でも1%ほど遅いことが分かった.
この結果は,この領域では断熱的かつ均質であるという仮定が破綻していることを示唆する.
また,地球流体核表面の地形を推定するための新たなデータを検討し,予備的な結果を得た.特徴的なパターンとして,環太平洋地域,中央太平洋,アフリカ直下で凹んでいることが挙げられる.

Research Products

• [Journal Article] On the vertical extent of the large low shear velocity province beneath the South Pacific Superswell (2009)
  • Author(s): Tanaka, S
  • Journal Title: Geophys. Res. Lett 36 Pages: L07305, doi:10.1029/2009 GL037160
  • Peer Reviewed
• [Journal Article] Possibility of a low P-wavevelocity layer in the outermost core from global SmKS waveforms (2007)
  • Author(s): Tanaka, S
  • Journal Title: Planet. Sci. Lett 259 Pages: 486-499
  • Peer Reviewed
• [Presentation] Core-mantle boundary topography from P4KP-PcP differential travel times: Implications for mantle dynamics (2009)
  • Author(s): Tanaka, S
  • Organizer: inal Stagnant Slab Project International Symposium on DEEP SLAB and MANTLE DYNAMICS
  • Place of Presentation: Kyoto
  • Year and Date: 2009-02-26
• [Presentation] et al., S-wave velocity structure beneath the South Pacific Superswell derived from passive seismic experiments (2008)
  • Author(s): Tanaka, S
  • Organizer: AGU 2008 Fall Meeting
  • Place of Presentation: San Francisco, USA
  • Year and Date: 2008-12-15
• [Presentation] The topography of the core-mantle boundary from P4KP-PcP travel time (2008)
  • Author(s): Tanaka, S
  • Organizer: SEDI
  • Place of Presentation: Kunming, China
  • Year and Date: 2008-07-27
• [Presentation] P4KP-PcP 走時によるコア・マントル境界の地形:インバージョンの試み (2008)
  • Author(s): 田中 聡
  • Organizer: 日本地球惑星科学連合2008年大会
  • Place of Presentation: 幕張
  • Year and Date: 2008-05-28
• [Presentation] New seismological attempts to study the top of the Earth's core (2007)
  • Author(s): Tanaka, S
  • Organizer: AGU 2007 Fall Meeting
  • Place of Presentation: San Francisco, USA
  • Year and Date: 2007-12-10
• [Presentation] J-array とIMS-array で観測された P4KP-PcP 走時による CMB 地形モデルの 検討 (2007)
  • Author(s): 田中 聡
  • Organizer: 日本地震学会2007年度秋季大会
  • Place of Presentation: 仙台
  • Year and Date: 2007-10-24
• [Presentation] Seismological structure of the Earth's core: Recent progress and implication (2007)
  • Author(s): Tanaka, S
  • Organizer: The 21st century COE International Symposium at Tohoku University
  • Place of Presentation: Sendai
  • Year and Date: 2007-09-19
• [Presentation] Seismic structure of the outer core from P4KP-PcP travel times observed with the J-array and IMS arrays (2007)
  • Author(s): Tanaka,S
  • Organizer: IUGG 2007
  • Place of Presentation: Perugia, Italy
  • Year and Date: 2007-07-02
• [Presentation] Search for a stably stratified layer in the outermost core using global SmKS waveforms (2006)
  • Author(s): Tanaka, S
  • Organizer: WPGM 2006
  • Place of Presentation: Beijing, China
  • Year and Date: 2006-07-25
• [Presentation] A study on the seismic structure of the core-mantle boundary using global SmKS waveforms (2006)
  • Author(s): Tanaka, S
  • Organizer: SEDI 2006
  • Place of Presentation: Prague, Czech Republic
  • Year and Date: 2006-07-10
• [Presentation] SmKS waves observed by dense mobile broadband seismic arrays (2006)
  • Author(s): Tanaka, S
  • Organizer: IRIS 18th Annual Workshop
  • Place of Presentation: Tucson, USA
  • Year and Date: 2006-06-09
• [Presentation] Search for lateral variation in the Earth's outermost core by using a global data set of SmKS waveform (2006)
  • Author(s): 田中 聡
  • Organizer: 日本地球惑星科学連合2006 年大会
  • Place of Presentation: 幕張
  • Year and Date: 2006-05-17
• [Presentation] Seismological structure of the Earth's core: Implications for geomagnetism (2006)
  • Author(s): Tanaka, S
  • Organizer: JGU 2006
  • Place of Presentation: Makuhari
  • Year and Date: 2006-05-17