Japan Geoscience Union Meeting 2021

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[E] Oral

M (Multidisciplinary and Interdisciplinary) » M-IS Intersection

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

Sun. Jun 6, 2021 1:45 PM - 3:15 PM Ch.22 (Zoom Room 22)

convener:Katsumi Hattori(Department of Earth Sciences, Graduate School of Science, Chiba University), Dimitar Ouzounov(Center of Excellence in Earth Systems Modeling & Observations (CEESMO) , Schmid College of Science & Technology Chapman University, Orange, California, USA), Jann-Yenq LIU(Department of Space Science and Engineering, National Central University, Taiwan), Qinghua Huang(Peking University), Chairperson:Peng Han(Southern University of Science and Technology, Shenzhen, China), Xuemin Zhang(Institute of Earthquake Forecasting, China Earthquake Administration)

2:00 PM - 2:15 PM

[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)

Keywords: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.