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

0376939 - ÚFA 2013 RIV IT eng J - Journal Article
Píša, David - Němec, F. - Parrot, M. - Santolík, Ondřej
Attenuation of electromagnetic waves at the frequency ~1.7 kHz in the upper ionosphere observed by the DEMETER satellite in the vicinity of earthquakes.
Annals of Geophysics. Roč. 55, č. 1 (2012), s. 157-163. ISSN 1593-5213. E-ISSN 2037-416X
R&D Projects: GA MŠMT ME09107; GA ČR GA205/09/1253
Grant - others:European Community(XE) FP7:262005
Institutional research plan: CEZ:AV0Z30420517
Keywords : DEMETER satellite * pre-seismic activity * statistical study * waves and wave analysis
Subject RIV: BL - Plasma and Gas Discharge Physics
Impact factor: 1.138, year: 2012
http://www.annalsofgeophysics.eu/index.php/annals/article/view/5276

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. For this study a robust two-step data processing has been used. We confirm the previously reported results of a very small, but statistically significant, decrease in VLF 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 earthquakes with lower depth. This can be explained by increases in the cut-off frequency of the Earth ionosphere waveguide caused by imminent earthquakes.
Permanent Link: http://hdl.handle.net/11104/0209218