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| Titel |
Day-time variations of foF2 connected to strong earthquakes |
| VerfasserIn |
E. V. Liperovskaya, V. V. Bogdanov, P.-F. Biagi, C.-V. Meister, V. A. Liperovsky, M. V. Rodkin |
| 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 ; 9, no. 1 ; Nr. 9, no. 1 (2009-01-19), S.53-59 |
| Datensatznummer |
250006606
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| Publikation (Nr.) |
 copernicus.org/nhess-9-53-2009.pdf |
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| Zusammenfassung |
| The statistical analysis of the characteristic frequency foF2 of the Earth's
ionosphere averaged over mid-day hours – from 11:00 till 17:00 h LT – is
carried out. Disturbances of foF2 connected to earthquakes are considered on
the background of seasonal, geomagnetic, 11-years and 27-days solar
variations. A special normalized parameter F is introduced, which
represents the almost seasonal-independent part of foF2. Days with high solar
(Wolf number >100) and geomagnetic (∑Kp>30) activity are
excluded from the analysis. Events with magnitude M>5, distance from
the sounding station R<500 km and depth h<70 km are taken into
account. The superimposed epoches' method is used to determine the temporal
dependence of F. It is found that F increases about 3–6 days before
the earthquakes and then decreases one day – two days before the shock. The
decreased values of F continue to exist two-three days after events with
M>5.5. The obtained phenomenon depends on the magnitude of the
earthquake. For events with M>5.5, the reliability of the effect is
larger than 95%. For data of more than 80 earthquakes in the vicinity of
Petropavlovsk-Kamchatsky and more than 200 earthquakes in the vicinity of
Tokyo analogous results are obtained. |
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