Journal cover Journal topic
Natural Hazards and Earth System Sciences An interactive open-access journal of the European Geosciences Union
Nat. Hazards Earth Syst. Sci., 7, 625-628, 2007
https://doi.org/10.5194/nhess-7-625-2007
© Author(s) 2007. This work is licensed under
the Creative Commons Attribution-NonCommercial-ShareAlike 2.5 License.
 
26 Oct 2007
Observation evidences of atmospheric Gravity Waves induced by seismic activity from analysis of subionospheric LF signal spectra
A. Rozhnoi1, M. Solovieva1, O. Molchanov1, P.-F. Biagi2, and M. Hayakawa3 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.

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, https://doi.org/10.5194/nhess-7-625-2007, 2007.
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