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Observation evidences of atmospheric Gravity Waves induced by seismic activity from analysis of subionospheric LF signal spectra
1Institute of the Earth Physics, RAS, Bolshaya Gruzinskaya 10, Moscow, Russia
2University of Bari, Bari, Italy
3University of Electro-Communications, Chofu, Tokyo, Japan
Abstract. We analyze variations of the LF subionospheric signal amplitude and phase from JJY transmitter in Japan (F=40 kHz) received in Petropavlovsk-Kamchatsky station during seismically quiet and active periods including also periods of magnetic storms. After 20 s averaging, the frequency range of the analysis is 0.28–15 mHz that corresponds to the period range from 1 to 60 min. Changes in spectra of the LF signal perturbations are found several days before and after three large earthquakes, which happened in November 2004 (M=7.1), August 2005 (M=7.2) and November 2006 (M=8.2) inside the Fresnel zone of the Japan-Kamchatka wavepath. Comparing the perturbed and background spectra we have found the evident increase in spectral range 10–25 min that is in the compliance with theoretical estimations on lithosphere-ionosphere coupling by the Atmospheric Gravity Waves (T>6 min). Similar changes are not found for the periods of magnetic storms.
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Citation: Rozhnoi, A., Solovieva, M., Molchanov, O., Biagi, P.-F., and Hayakawa, M.: Observation evidences of atmospheric Gravity Waves induced by seismic activity from analysis of subionospheric LF signal spectra, Nat. Hazards Earth Syst. Sci., 7, 625-628, 2007. Bibtex EndNote Reference Manager
