3D Tomography of the Ionospheric Anomalies Before the 2010 Maule Earthquake, Chile: Comparison with the 2011 Tohoku-oki and 2015 Illapel Earthquakes

Ihsan Naufal Muafiry

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セッション記号 M (領域外・複数領域) » M-IS ジョイント

[M-IS08] Interdisciplinary studies on pre-earthquake processes

2021年6月6日(日) 13:45 〜 15:15 Ch.22 (Zoom会場22)

コンビーナ:服部克巳(千葉大学大学院理学研究科)、Ouzounov Dimitar(Center of Excellence in Earth Systems Modeling & Observations (CEESMO) , Schmid College of Science & Technology Chapman University, Orange, California, USA)、劉正彦(国立中央大学太空科学研究所)、Qinghua Huang(Peking University)、座長:韓鵬(南方科技大学)、Xuemin Zhang(Institute of Earthquake Forecasting, China Earthquake Administration)

14:00 〜 14:15

[MIS08-08] 3D Tomography of the Ionospheric Anomalies Before the 2010 Maule Earthquake, Chile: Comparison with the 2011 Tohoku-oki and 2015 Illapel Earthquakes

*Ihsan Naufal Muafiry¹、Kosuke Heki¹ (1.Hokkaido University, Japan)

キーワード：3D tomography, GNSS, Pre-seismic Ionospheric Anomaly

This study compares the 3D structure of ionospheric electron density anomalies immediately before the three megathrust earthquakes, i.e. 2011 Mar. 11 Tohoku-Oki (Muafiry & Heki, JGR 2020), 2015 Sep.16 Illapel (He & Heki, JGR 2018), and the 2010 Feb. 27 Maule, Chile (new study), earthquakes, revealed using slant-TEC residuals as inputs to 3D tomographic inversion. For the Maule earthquake, we used 371 TEC data obtained using 7 satellites and 91 ground GNSS stations mainly in Chile and Argentine. The tomography results showed that the pre-seismic ionospheric anomaly in each case has following similarities; (1) They are composed of pairs of low-altitude positive and high-altitude negative electron density anomalies. (2) They occur above the land area close to the submarine faults. (3) They have clear onsets a few tens of minutes before earthquakes (~40 min before 2011 Tohoku-oki, and Maule, and ~20 minutes before the Illapel earthquakes) and grow with decaying rates. Muafiry & Heki (2020) hypothesized the physical process consistent with such 3D structure. We will also compare strengths and dimensions of the electron density anomalies before these three earthquakes.