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| Titel |
Modification of the low-latitude ionosphere before the 26 December 2004 Indonesian earthquake |
| VerfasserIn |
I. E. Zakharenkova, A. Krankowski, I. I. Shagimuratov |
| 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 ; 6, no. 5 ; Nr. 6, no. 5 (2006-09-25), S.817-823 |
| Datensatznummer |
250003715
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| Publikation (Nr.) |
 copernicus.org/nhess-6-817-2006.pdf |
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| Zusammenfassung |
| This paper investigates the features of pre-earthquake ionospheric anomalies
in the total electron content (TEC) data obtained on the basis of regular
GPS observations from the IGS network. For the analysis of the ionospheric
effects of the 26 December 2004 Indonesian earthquake, global TEC maps were
used. The possible influence of the earthquake preparation processes on the
main low-latitude ionosphere peculiarity – the equatorial anomaly – is
discussed. Analysis of the TEC maps has shown that modification of the
equatorial anomaly occurred a few days before the earthquake. For 2 days
prior to the event, a positive effect was observed in the daytime
amplification of the equatorial anomaly. Maximal enhancement in the crests
reached 20 TECU (50–60%) relative to the non-disturbed state. In
previous days, during the evening and night hours (local time), a specific
transformation of the TEC distribution had taken place. This modification
took the shape of a double-crest structure with a trough near the epicenter,
though usually in this time the restored normal latitudinal distribution
with a maximum near the magnetic equator is observed. It is assumed that
anomalous electric field generated in the earthquake preparation zone could
cause a near-natural "fountain-effect" phenomenon and might be a possible
cause of the observed ionospheric anomaly. |
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