Attenuation of electromagnetic waves at the frequency approximately 1.7 kHz in the upper ionosphere observed by the DEMETER satellite in the vicinity of earthquakes

Abstract : The DEMETER satellite was the first satellite specifically dedicated to the recording of electromagnetic phenomena connected with seismic activity. Almost 6.5 years of measurements provide good opportunities to analyze a unique dataset with global Earth coverage. We present the results of a statistical study of the intensity of very low frequency electromagnetic waves recorded in the upper ionosphere. Robust two-step data processing has been used. The expected unperturbed distribution of the power spectral densities of electromagnetic emissions was calculated first. Then, the power spectral densities measured in the vicinities of earthquakes are compared with the unperturbed distribution and are examined for the presence of uncommon effects related to seismic activity. The statistical significance of the observed effects is evaluated. We confirm the previously reported results of a very small, but statistically significant, decrease in wave intensities a few hours before times of main shocks using this much larger dataset. The wave intensity decrease at a frequency of about 1.7 kHz is observed only during the night and only for shallow earthquakes. This can potentially be explained by increases in the cut-off frequency of the Earth ionosphere waveguide caused by imminent earthquakes.
Type de document :
Article dans une revue
Annals of Geophysics, 2012, 55, 7 p. 157-163. 〈10.4401/ag-5276〉
Liste complète des métadonnées

Littérature citée [15 références]  Voir  Masquer  Télécharger

https://hal-insu.archives-ouvertes.fr/insu-01295634
Contributeur : Nathalie Rouchon <>
Soumis le : lundi 20 novembre 2017 - 09:59:13
Dernière modification le : jeudi 11 janvier 2018 - 06:24:16
Document(s) archivé(s) le : mercredi 21 février 2018 - 12:28:08

Fichier

5276-9876-1-PB.pdf
Accord explicite pour ce dépôt

Identifiants

Collections

Citation

David Píša, Frantisek Nemec, Michel Parrot, Ondrej Santolik. Attenuation of electromagnetic waves at the frequency approximately 1.7 kHz in the upper ionosphere observed by the DEMETER satellite in the vicinity of earthquakes. Annals of Geophysics, 2012, 55, 7 p. 157-163. 〈10.4401/ag-5276〉. 〈insu-01295634〉

Partager

Métriques

Consultations de la notice

443

Téléchargements de fichiers

16