Mysterious behavior of ionosphere immediately before and after large earthquakes

• Project/Area Number: 26400442
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Solid earth and planetary physics
• Research Institution: Hokkaido University
• Principal Investigator: Heki Kosuke 北海道大学, 理学研究院, 教授 (30280564)
• Project Period (FY): 2014-04-01 – 2017-03-31
• Project Status: Completed (Fiscal Year 2016)
• Budget Amount: ¥3,770,000 (Direct Cost: ¥2,900,000、Indirect Cost: ¥870,000); Fiscal Year 2016: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000); Fiscal Year 2015: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000); Fiscal Year 2014: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
• Keywords: GNSS / TEC / 電離圏擾乱 / 地震前兆 / 三次元構造 / 電離圏全電子数 / トモグラフィー / マグニチュード / チリ地震 / 宇宙天気 / 地震予知 / 短期予知 / 衛星測位システム / 地磁気変動

Outline of Final Research Achievements

I studied anomalies of ionospheric total electron content (TEC) related to earthquakes using GNSS satellites. The quantitative relationship between the magnitude and coseismic TEC pulsation has been established. Preseismic ionospheric changes have been discovered shortly after the 2011 Tohoku-oki earthquake. I collected similar observation cases before over ten large earthquakes with moment magnitudes (Mw) 7.8-9.2, and revealed several kinds of Mw dependences of these anomalies, e.g. precursor times (40 min. for M9 and 20 min. for M8 events), spatial dimensions, and strength of preseismic changes in terms of changing rate of TEC. From 3-D structure of ionospheric anomalies, it was found that the preseismic ionospheric anomalies are due to positive electric charges on the surface.

Research Products

• [Journal Article] Three-dimensional distribution of ionospheric anomalies prior to three large earthquakes in Chile (2016)
  • Author(s): He L. and K. Heki
  • Journal Title: Geophysical Research Letters Volume: 43 Issue: 14 Pages: 7287-7293
  • DOI: 10.1002/2016gl069863
  • NAID: 120005951958
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Mw dependence of preseismic ionospheric electron enhancements (2015)
  • Author(s): Heki, K. and Y. Enomoto
  • Journal Title: J. Geophys. Res. Space Phys. Volume: 120 Issue: 8 Pages: 7006-7020
  • DOI: 10.1002/2015ja021353
  • Peer Reviewed / Acknowledgement Compliant
• [Journal Article] Morphology and dynamics of daytime mid-latitude sporadic-E patches revealed by GPS total electron content observations in Japan (2015)
  • Author(s): Maeda, J. and K. Heki
  • Journal Title: Earth Planets and Space Volume: 67 Issue: 1 Pages: 89-89
  • DOI: 10.1186/s40623-015-0257-4
  • NAID: 120005625299
  • Peer Reviewed / Open Access
• [Journal Article] Atmospheric resonant oscillations by the 2014 eruption of the Kelud volcano, Indonesia, observed with the ionospheric Total Electron Contents and seismic signal (2015)
  • Author(s): Nakashima, Y., K. Heki, A. Takeo, M. Cahyadi, A. Aditiya, and K. Yoshizawa
  • Journal Title: Earth Planet. Sci. Lett. Volume: 434 Pages: 112-116
  • DOI: 10.1016/j.epsl.2015.11.029
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Imaging the midlatitude sporadic-E plasma patches with a coordinated observation of space-borne InSAR and GPS total electron content (2015)
  • Author(s): Maeda, J., T. Suzuki, M. Furuya and K. Heki
  • Journal Title: Geophys. Res. Lett. Volume: 43 Issue: 4 Pages: 1419-1425
  • DOI: 10.1002/2015gl067585
  • NAID: 120005841310
  • Peer Reviewed
• [Journal Article] Coseismic ionospheric disturbance of the large strike-slip earthquakes in North Sumatra in 2012: Mw dependence of the disturbance amplitudes (2015)
  • Author(s): Cahyadi, M.N. and K. Heki
  • Journal Title: Geophys. Jour. International Volume: 200 Issue: 1 Pages: 116-129
  • DOI: 10.1093/gji/ggu343
  • NAID: 120005602529
  • Peer Reviewed
• [Journal Article] Preseismic TEC changes for Tohoku-Oki earthquake: Comparisons between simulations and observations (2015)
  • Author(s): Kuo, C.L., L.C. Lee, and K. Heki
  • Journal Title: Terr. Atmos. Ocean. Sci. Volume: 26 Issue: 1 Pages: 63-72
  • DOI: 10.3319/tao.2014.08.19.06(grt)
  • NAID: 120005603797
  • Peer Reviewed
• [Journal Article] Reply to comment by K. Heki and Y. Enomoto on "Preseismic ionospheric electron enhancements revisited" (2014)
  • Author(s): Heki, K. and Y. Enomoto
  • Journal Title: Jour. Geophys. Res. Space Phys. Volume: 119 Issue: 7 Pages: 6016-6018
  • DOI: 10.1002/2014ja020223
  • NAID: 120005530832
  • Peer Reviewed
• [Journal Article] GNSSデータに地震前兆を探す (2014)
  • Author(s): 日置幸介
  • Journal Title: 計測と制御 Volume: 53 Pages: 469-472
  • NAID: 130005457939
• [Presentation] Preseismic ionospheric anomalies: Current overview and perspective (2017)
  • Author(s): Heki, K., L. He, and I. N. Muafiry
  • Organizer: 2nd Geo-lab and RISH Joint Workshop on GNSS and SAR Technologies for Atmospheric Sensing
  • Place of Presentation: 京都府宇治市京都大学
  • Int'l Joint Research / Invited
• [Presentation] Ionospheric anomalies immediately before large earthquakes: Observation by GNSS-TEC (2016)
  • Author(s): Heki, K.
  • Organizer: ICG+2016
  • Place of Presentation: 上海天文台（中国、上海市）
  • Year and Date: 2016-07-28
  • Int'l Joint Research / Invited
• [Presentation] チリで発生した三つの大地震の直前に起こった電離圏異常の時空間構造 (2016)
  • Author(s): 日置幸介、賀黎明
  • Organizer: JPGU
  • Place of Presentation: 千葉県千葉市幕張メッセ
  • Year and Date: 2016-05-22
• [Presentation] 3-D structure of ionospheric anomalies immediately before large earthquakes: The 201I llapel (Mw8.3) and 2016 Kumamoto (Mw7.0) cases (2016)
  • Author(s): Heki, K., L. He, and I. N. Muafiry
  • Organizer: American Geophysical Union Fall Meeting
  • Place of Presentation: サンフランシスコ市国際会議場（米国、カリフォルニア州）
  • Int'l Joint Research
• [Presentation] 熊本地震の直前に現れたstagnant MSTID (2016)
  • Author(s): 日置幸介、賀黎明
  • Organizer: 日本地震学会秋季大会
  • Place of Presentation: 名古屋国際会議場（愛知県、名古屋市）
• [Presentation] Mw dependence of ionospheric electron enhancement immediately before large earthquakes (2015)
  • Author(s): Heki, K. and L. He
  • Organizer: アメリカ地球物理連合秋季大会
  • Place of Presentation: 米国サンフランシスコ市モスコーニ国際会議場
  • Year and Date: 2015-12-14
  • Int'l Joint Research / Invited
• [Presentation] Monitoring Ionospheric Electrons with GNSS for Very Short-term Earthquake Prediction (2015)
  • Author(s): Heki, K.
  • Organizer: The 7th International Conference on Geo-information Technologies for Natural Disaster
  • Place of Presentation: アラブ首長国連合アルアイン市アルアイン大学
  • Year and Date: 2015-12-08
  • Int'l Joint Research / Invited
• [Presentation] 地震直前の電離圏電子数上昇のMw依存性 (2015)
  • Author(s): 日置幸介、榎本祐嗣
  • Organizer: 日本測地学会秋季大会
  • Place of Presentation: 福岡県福岡市西新ホール
  • Year and Date: 2015-10-14
• [Presentation] Ionospheric electron enhancement 20-80 min. before large earthquakes: Examples from 8 earthquakes with Mw 8.2 -9.2 (2015)
  • Author(s): Heki, K. and Y. Enomoto
  • Organizer: The 26th General Assembly of IUGG
  • Place of Presentation: チェコ共和国プラハ市国際会議場
  • Year and Date: 2015-06-23
  • Int'l Joint Research
• [Presentation] 2011年東北沖地震発生40分前に始まったGPS-TECと地磁気偏角の前兆変動について (2015)
  • Author(s): 日置幸介、榎本祐嗣
  • Organizer: 日本地球惑星科学連合大会
  • Place of Presentation: 千葉県千葉市幕張メッセ
  • Year and Date: 2015-05-24
• [Presentation] 2015年ネパール地震の約20分前に発生した電離圏全電子数の上昇 (2015)
  • Author(s): 日置幸介
  • Organizer: 日本地球惑星科学連合大会
  • Place of Presentation: 千葉県千葉市幕張メッセ
  • Year and Date: 2015-05-24
• [Presentation] Preseismic ionospheric electron enhancements: A few remaining problems (2014)
  • Author(s): Heki, K.
  • Organizer: AOGS
  • Place of Presentation: ホテルロイトン札幌（札幌市）
  • Year and Date: 2014-07-30 – 2014-08-01
• [Presentation] Some problems in preseismic ionospheric electron enhancements (2014)
  • Author(s): Heki, K.
  • Organizer: GENAH2014
  • Place of Presentation: 松島大観荘（宮城県松島町）
  • Year and Date: 2014-07-22 – 2014-07-26
• [Presentation] 再び地震直前の電離圏電子数上昇について：移動性の識別と受信機周波数間バイアスの推定 (2014)
  • Author(s): 日置幸介
  • Organizer: JPGU
  • Place of Presentation: パシフィコ横浜(横浜市）
  • Year and Date: 2014-04-28 – 2014-05-02