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| Titel |
Exalting in atmospheric tides as earthquake precursor |
| VerfasserIn |
P. F. Biagi, R. Piccolo, V. Capozzi, A. Ermini, S. Martellucci, C. Bellecci |
| 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 ; 3, no. 3/4 ; Nr. 3, no. 3/4, S.197-201 |
| Datensatznummer |
250000677
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| Publikation (Nr.) |
 copernicus.org/nhess-3-197-2003.pdf |
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| Zusammenfassung |
| During February–March
1998, we observed a significant increase (6–8 dB) in the electric field
of the CZE (f = 270 kHz, Czech Republic) broadcasting station at a site
named AS and located in central Italy. On 13 March 1998 an earthquake (M =
5.2) occurred in Slovenia, starting a strong seismic crisis (M = 6.0 on 12
April, M = 5.1 on 6 May). The distances of the epicentres from the radio
receiver were over 400 km, but the epicentres are located in a zone that
is in the middle of the CZE-AS path. Previously, we advanced the
hypothesis that the increase of radio-signal electric field detected could
be a precursor of the Slovenia seismic crisis. At the purpose to precise
the connection between this radio anomaly and the preparatory phase of the
earthquakes, we analysed in detail the data collected. At first we carried
out a FFT on the data and clear harmonic components with period 0.5d, 1d,
14d, 28d and 365d were revealed. These periods are characteristic of
gravity tides and therefore, it seems reasonable to consider the previous
harmonics in the electric field of the radio signal as components related
to tides of the atmosphere, assuming as tides of the atmosphere only the
linear action of gravity tides on atmosphere. Then, we carried out band
pass filters on our data and we discovered that the February–March 1998
increase is mainly related to an exalting of the harmonics with period
0.5d, 1d, 14d and 28d, i.e. of the (semi)monthly and (semi)diurnal
atmospheric tidal components in the radio signal. Supposing that this
exalting is produced by a corresponding exalting of the atmospheric tides
we propose a model able to explain the production of such an effect during
the preparatory phase of the Slovenia earthquakes. |
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