Ionospheric Monitoring of Large Earthquakes Rupture Complexity with Waveform Modeling Support.
Abstract
Past studies have shown that the largest megathrust earthquakes (> Mw 9) trigger complex co-seismic ionospheric signals observed in Total Electron Content (TEC) measurements derived from Global Navigation System Satellites (GNSS). Precisely, the imprint of the slip rupture heterogeneities on the upper atmosphere clearly appear at the beginning of the signature. The Mw 9.2 Sumatra-Andaman earthquake of 26 December 2004 and the Mw 9.0 Tohoku-Oki earthquake of 11 March 2011 could be resolved as superpositions of single acoustic sources, with each source triggering an N-shape wave. These signals demonstrate the efficient dynamic coupling that arises between the Earth's surface motion (mostly the vertical component), the surrounding atmosphere, and the ionosphere. Here we investigate lower magnitude earthquakes and highlight that such intricate N-wave patterns are frequently visible in co-seismic ionospheric waveforms recorded with the proper observation geometry. We revisit past seismic events such as the Mw 7.8 Kaikoura earthquake of 13 November 2016, the Mw 7.4 Sanriku-Oki Earthquake of 9 March 2011, or the Mw 7.2 Van earthquake of 23 October 2011 to illustrate further that the ionosphere can resolve details of ruptures of events with moment magnitudes down to 7.0. To support this close look on the morphology of ionospheric seismic waveforms registered after strong and shallow earthquakes, we make use of coseismic GNSS-TEC perturbation full-waveform modeling. Our modeling approaches are based on acoustic ray tracing (IonoSeis software) and the spectral element method (SPECFEM-3D software). We conclude with our perspectives offered by these new findings toward a rapid characterization of earthquake sources using GNSS satellites ionospheric measurements.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFMNH33C0925R
- Keywords:
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- 4301 Atmospheric;
- NATURAL HAZARDS;
- 4302 Geological;
- NATURAL HAZARDS;
- 4305 Space weather;
- NATURAL HAZARDS;
- 4315 Monitoring;
- forecasting;
- prediction;
- NATURAL HAZARDS