Anomalous modification of the ionospheric total electron content prior to the 26 September 2005 Peru earthquake

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 International GNSS Service (IGS) network. For the analysis of the ionospheric effects of the 26 September 2005 Peru earthqu...

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Bibliographic Details
Published in:	Journal of atmospheric and solar-terrestrial physics Vol. 70; no. 15; pp. 1919 - 1928
Main Authors:	Zakharenkova, I.E., Shagimuratov, I.I., Tepenitzina, N.Yu, Krankowski, A.
Format:	Journal Article
Language:	English
Published:	Elsevier Ltd 01-12-2008
Subjects:	Earthquake Equatorial anomaly Ionosphere Total electron content Peru Equatorial anomaly Earthquake Total electron content Ionosphere
Online Access:	Get full text
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Summary:	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 International GNSS Service (IGS) network. For the analysis of the ionospheric effects of the 26 September 2005 Peru earthquake, Global Ionospheric Maps (GIMs) of TEC 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. In previous days, during the evening and night hours (local time—LT), 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. Additional measurements (CHAMP satellite) have also confirmed the presence of this structure. To compare the vertical TEC measurements obtained with GPS satellite signals (GPS TEC), the International Reference Ionosphere, IRI-2001, was used for calculating the IRI TEC.
Bibliography:	ObjectType-Article-2 SourceType-Scholarly Journals-1 ObjectType-Feature-1 content type line 23
ISSN:	1364-6826 1879-1824
DOI:	10.1016/j.jastp.2008.06.003