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| Titel |
Decrease in the electric intensity of VLF/LF radio signals and possible connections |
| VerfasserIn |
P. F. Biagi, L. Castellana, T. Maggipinto, G. Maggipinto, A. Minafra, A. Ermini, V. Capozzi, G. Perna, M. Solovieva, A. Rozhnoi, O. A. Molchanov, M. Hayakawa |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1561-8633
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| Digitales Dokument |
URL |
| Erschienen |
In: Natural Hazards and Earth System Science ; 7, no. 3 ; Nr. 7, no. 3 (2007-06-21), S.423-430 |
| Datensatznummer |
250004547
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| Publikation (Nr.) |
 copernicus.org/nhess-7-423-2007.pdf |
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| Zusammenfassung |
| In February 2002, a receiver was put into operation at the Department of
Physics of Bari University (Southern Italy) to record VLF-LF radio
signals. The intensity and the phase of the signals transmitted by GB (f=16 kHz,
United Kingdom), FR (f=20.9 kHz, France), GE (f=23.4 kHz, Germany), IC
(f=37.5 kHz, Island) and IT (f=54 kHz, Sicily, Italy) has been monitored
with a 5 s sampling rate. The intensity raw data averaged over 10 min, from
February 2002 to April 2006, have been analysed. Several decreases of the
electric field intensity of the radio signals with a duration of some days
were revealed, generally occurring in not concomitant periods. The GE signal
decreases systematically in winter and summer each year and so, it could be
supposed that such decreases are related to the transmitter. On the
contrary, all the other decreases pointed out are sporadic and the previous
justification does not seem realistic. On the time occurrence of these
decreases, the geomagnetic activity, the meteorological conditions in the
receiver area and the regional seismic activity were investigated. The main
result is that, generally, a pre or post seismic effect seems to
give the most convincing justification. The effect seems to appear for
earthquakes with magnitude M≥4.3, when the epicentres are
within the third Fresnel zone of the radio signals or near enough
to some radio path. |
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