Nostradamus: The radar that wanted to be a seismometer

Giovanni Occhipinti (1) , Philippe Dorey (2) , Thomas Farges (3) , Philippe Lognonné (1)

1 IPGP (UMR_7154) - Institut de Physique du Globe de Paris
2 ONERA - The French Aerospace Lab [Palaiseau]
3 DAM - Direction des Applications Militaires

Surface waves emitted after large earthquakes are known to induce, by dynamic coupling, atmospheric infrasonic waves propagating upward through the neutral and ionized atmosphere. Those waves have been detected in the past at ionospheric heights using a variety of techniques, such as HF Doppler sounding or GPS receivers. The HF Doppler technique, particularly sensitive to the ionospheric signature of Rayleigh waves is used here to show ionospheric perturbations consistent with the propagation of Rayleigh wave phases R1 and R2 following the Sumatra earthquake on the 28 March 2005 (M = 8.6). This is in our knowledge the first time that the phase R2 is detected by ionospheric sounding. In addition, we prove here that the ionospheric signature of R2 is also observed by over-the- horizon (OTH) Radar. The latter was never used before to detect seismic signature in the ionosphere. Adding the OTH Radar to the list of the "ionospheric seismometers" we discuss and compare the performances of the three different instruments mentioned above, namely HF Doppler sounding, GPS receivers and OTH radar.

Mots clés: ATMOSPHERIC OSCILLATIONS; SURFACE-WAVES; EARTH MODEL; IONOSPHERE; EXCITATION

Domaines: Géophysique [physics.geo-ph]

Giovanni Occhipinti, Philippe Dorey, Thomas Farges, Philippe Lognonné. Nostradamus: The radar that wanted to be a seismometer. Geophysical Research Letters, 2010, 37 (18), pp.L18104. ⟨10.1029/2010GL044009⟩. ⟨insu-02566137⟩