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., 10, 1487-1494, 2010
© Author(s) 2010. This work is distributed under
the Creative Commons Attribution 3.0 License.
09 Jul 2010
Decrease of VLF transmitter signal and Chorus-whistler waves before l'Aquila earthquake occurrence
M. Y. Boudjada1, K. Schwingenschuh1, R. Döller2, A. Rohznoi3, M. Parrot4, P. F. Biagi5, P. H. M. Galopeau6, M. Solovieva3, O. Molchanov3, H. K. Biernat1,7, G. Stangl8, H. Lammer1, I. Moldovan9, W. Voller1, and M. Ampferer2 1Space Research Institute, Austrian Academy of Sciences, Graz, Austria
2Institute of Physics, Department of Geophysics, Astronomy and Meteorologie, KF University Graz, Graz, Austria
3Institute of the Earth Physics, Russian Academy of Sciences, Moscow, Russia
4Laboratoire de Physique et Chimie de l'Environnement et de l'Espace, Orléans, France
5Department of Physics, University of Bari, Bari, Italy
6Laboratoire Atmosphères, Milieux, Observations Spatiales, CNRS, UVSQ, Guyancourt, France
7Institute of Physics, Department of Theoretical Physics, KF University Graz, Graz, Austria
8Federal Office of Metrology and Surveying, Vienna, Austria
9National Institute of Research and Development for Earth Physics, Bucharest, Rumania
Abstract. We investigate the VLF emissions observed by the Instrument Champ Electrique (ICE) experiment onboard the DEMETER micro-satellite. We analyze intensity level variation 10 days before and after the occurrence of l'Aquila earthquake (EQ). We found a clear decrease of the VLF received signal related to ionospheric whistler mode (mainly Chorus emission) and to signal transmitted by the DFY VLF station in Germany, few days (more than one week) before the earthquake. The VLF power spectral density decreases of more than two orders of magnitude until the EQ, and it recovers to normal levels just after the EQ occurrence. The geomagnetic activity is principally weak four days before EQ and increases again one day before l'Aquila seismic event. Our results are discussed in the frame of short- and long-terms earthquakes prediction focusing on the crucial role of the magnetic field of the Earth.

Citation: Boudjada, M. Y., Schwingenschuh, K., Döller, R., Rohznoi, A., Parrot, M., Biagi, P. F., Galopeau, P. H. M., Solovieva, M., Molchanov, O., Biernat, H. K., Stangl, G., Lammer, H., Moldovan, I., Voller, W., and Ampferer, M.: Decrease of VLF transmitter signal and Chorus-whistler waves before l'Aquila earthquake occurrence, Nat. Hazards Earth Syst. Sci., 10, 1487-1494,, 2010.
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