[S20-1] Earth and planetary space and remote sensing seismology; i.e., seismology without seismometers

[S20-1-01] Surface waves magnitude estimation from ionospheric signature of Rayleigh waves measured by Doppler sounder and OTH radar

^○Giovanni Occhipinti¹, Florent Aden-Antoniow¹, Virgile Rakoto¹, Aurelien Bablet¹, Jean-Philippe Molinie², Thomas Farges³, Philippe Lognonné¹ (1.Institut de Physique du Globe de Paris, Paris, France, 2.Office National d'Etudes et Recherches Aerospatiales, Palaiseau, France, 3.Commissariat Energie Atomique, Arpajon, France)

Surface waves emitted after large earthquakes are known to induce atmospheric infrasonic waves detectable at ionospheric heights using a variety of techniques, such as HF Doppler, GPS, and recently over-the-horizon (OTH) radar. The HF Doppler and OTH radar are particularly sensitive to the ionospheric signature of Rayleigh waves and are used here to show ionospheric perturbations consistent with the propagation of Rayleigh waves related to 28 and 10 events, with a magnitude larger than 6.2, detected by HF Doppler and OTH radar respectively. A transfert function is introduced to convert the ionospheric measurement into the correspondent ground displacement in order to compare it with classic seismometers. The ground vertical displacement, measured at the ground by seismometers, and measured at the ionospheric altitude by HF Doppler and OTH radar, is used here to compute surface wave magnitude. The presented results are under review for publication and are joined with some preliminary results of modeling of the Rayleigh wave signature in the ionosphere with the purpose of a full centroid moment tensor (CMT) estimation. The new magnitude and CMT estimation proves that ionospheric observations are useful seismological data to better cover the Earth and explore the seismology of other planets.