Articles | Volume 10, issue 7
Nat. Hazards Earth Syst. Sci., 10, 1487–1494, 2010

Special issue: Ground and satellite based observations during the time of...

Nat. Hazards Earth Syst. Sci., 10, 1487–1494, 2010

  09 Jul 2010

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 M. Y. Boudjada et al.
  • 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.