Decrease of VLF transmitter signal and Chorus-whistler waves before l'Aquila earthquake occurrence

Boudjada, M. Y.; Schwingenschuh, K.; Döller, R.; Rohznoi, A.; Parrot, M.; Biagi, P. F.; Galopeau, Patrick H. M.; Solovieva, M.; Molchanov, O. A.; Biernat, H. K.; Stangl, G.; Lämmer, H.; Moldovan, Iren-Adelina; Voller, W.; Ampferer, M.

doi:10.5194/nhess-10-1487-2010

Cited by 16 publications

(10 citation statements)

References 24 publications

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“…These electromagnetic waves play a controlling role in the dynamics of Earth's radiation belts, known as the van Allen belts (e.g., Trakhtengerts 1963, Kennel and Petschek 1966, Rycroft 1991, Meredith et al 2001, Thorne et al 2013. It is also important to mention that in the last two decades some authors (e.g., Hayakawa et al 1996, Molchanov and Hayakawa 1998, Němec et al 2009, Rozhnoi et al 2009, Boudjada et al 2010, Písa et al 2013 have used VLF observations to study precursor effects of earthquakes, an active field of research today.…”

Section: Introductionmentioning

confidence: 99%

Unusually high frequency natural VLF radio emissions observed during daytime in Northern Finland

Manninen¹,

Turunen²,

Клейменова

et al. 2016

Environ. Res. Lett.

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Geomagnetic field variations and electromagnetic waves of different frequencies are ever present in the Earth's environment in which the Earth's fauna and flora have evolved and live. These waves are a very useful tool for studying and exploring the physics of plasma processes occurring in the magnetosphere and ionosphere. Here we present ground-based observations of natural electromagnetic emissions of magnetospheric origin at very low frequency (VLF, 3-30 kHz), which are neither heard nor seen in their spectrograms because they are hidden by strong impulsive signals (sferics) originating in lightning discharges. After filtering out the sferics, peculiar emissions are revealed in these digital recordings, made in Northern Finland, at unusually high frequencies in the VLF band. These recently revealed emissions, which are observed for several hours almost every day in winter, contain short (∼1-3 min) burst-like structures at frequencies above 4-6 kHz, even up to 15 kHz; fine structure on the 1 s time scale is also prevalent. It seems that these whistler mode emissions are generated deep inside the magnetosphere, but the detailed nature, generation region and propagation behaviour of these newly discovered high latitude VLF emissions remain unknown; however, further research on them may shed new light on wave-particle interactions occurring in the Earth's radiation belts.

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Section: Introductionmentioning

confidence: 99%

Unusually high frequency natural VLF radio emissions observed during daytime in Northern Finland

Manninen¹,

Turunen²,

Клейменова

et al. 2016

Environ. Res. Lett.

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“…They found significant changes in the intensity and, in particular, in the signal-to-noise ratio before the EQ, which is considered to be a precursory ionospheric signature of the EQ. Boudjada et al (2008Boudjada et al ( , 2010 found a similar drop in the natural whistler VLF intensity level a few days before the EQs in the Adriatic region. Using different methods based mainly on the processing of the recorded dynamic spectrum, for each half orbit, authors lead to estimate the maximum of the intensity level through the observed channel frequency of ICE experiment.…”

Section: Detection Of Vlf Natural and Transmitters Signals Above Seismentioning

confidence: 63%

Investigation of TEC and VLF space measurements associated to L'Aquila (Italy) earthquakes

Stangl

Boudjada

Biagi

et al. 2011

Nat. Hazards Earth Syst. Sci.

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Abstract. In this study, we report on Total Electron Content (TEC) and Very Low Frequency (VLF) space measurements derived from Global Positioning System (GPS) and DEME-TER satellites, respectively. These measurements are associated with the earthquake (EQ) of a magnitude of 6.3, which occurred on 6 April 2009, in L'Aquila (Italy). Anomaly features are derived from the analysis of TEC and VLF observations recorded two weeks before and after the seismic event occurrence. A TEC map with an interpolated regional pixel resolution of 1 • × 1 • × 15 min in latitude, longitude and time was generated, allowing for the checking of a possible presence of disturbances over the L'Aquila region. This analysis is combined with the study of the time profile associated to the VLF flux density variations recorded by the Instrument Champ Electrique (ICE) experiment on-board DEMETER satellite. We discuss, on the one hand, the combination efficiency of the electronic density and the VLF electromagnetic measurements and, on the other hand, the difficulty to distinguish between global effects and regional ones related to the earthquake.

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“…Later, several investigations [Rozhnoi et al 2007, Muto et al 2008, Slominska et al 2008] confirmed this drop in VLF intensity. It is important to note that the decrease in the VLF intensity also concerns the natural whistler emissions, as reported by Boudjada et al [2010] for the L'Aquila earthquake (April 6, 2009). Hence, it was seen that the signal of the DFY transmitter was 'damped' from 5 days before to a minimum of one day before the earthquake.…”

Section: Very Low Frequency Transmitter Signals Over Seismic Regionsmentioning

confidence: 85%

Effects of solar and geomagnetic activities on the sub-ionospheric very low frequency transmitter signals received by the DEMETER micro-satellite

Boudjada

Schwingenschuh²,

Al-Haddad

et al. 2012

Annals of Geophysics

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In the framework of seismic precursor electromagnetic investigations, we analyzed the very low frequency (VLF) amplitude signals recorded by the Instrument Champ Electrique (ICE) experiment on board the DEMETER micro-satellite. The sun-synchronous orbits of the micro-satellite allowed us to cover an invariant latitude of between -65˚ and +65˚ in a time interval of about 40 min. We considered four transmitter signals emitted by

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Decrease of VLF transmitter signal and Chorus-whistler waves before l'Aquila earthquake occurrence

Cited by 16 publications

References 24 publications

Unusually high frequency natural VLF radio emissions observed during daytime in Northern Finland

Unusually high frequency natural VLF radio emissions observed during daytime in Northern Finland

Investigation of TEC and VLF space measurements associated to L'Aquila (Italy) earthquakes

Effects of solar and geomagnetic activities on the sub-ionospheric very low frequency transmitter signals received by the DEMETER micro-satellite

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