Changes in the ultra-low frequency wave field during the precursor phase to the Sichuan earthquake: DEMETER observations

Electromagnetic phenomena observed in association with increases in seismic activity have been studied for several decades. These phenomena are generated during the precursory phases of an earthquake as well as during the main event. Their occurrence during the precursory phases may be used in short...

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Bibliographic Details
Published inAnnales geophysicae (1988) Vol. 31; no. 9; pp. 1597 - 1603
Main Authors Walker, S. N., Kadirkamanathan, V., Pokhotelov, O. A.
Format Journal Article
LanguageEnglish
Published Copernicus GmbH 01.01.2013
Copernicus Publications
Subjects
Earthquakes
Electric fields
Electromagnetism
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Summary:Electromagnetic phenomena observed in association with increases in seismic activity have been studied for several decades. These phenomena are generated during the precursory phases of an earthquake as well as during the main event. Their occurrence during the precursory phases may be used in short-term prediction of a large earthquake. In this paper, we examine ultra-low frequency (ULF) electric field data from the DEMETER satellite during the period leading up to the Sichuan earthquake. It is shown that there is an increase in ULF wave activity observed as DEMETER passes in the vicinity of the earthquake epicentre. This increase is most obvious at lower frequencies. Examination of the ULF spectra shows the possible occurrence of geomagnetic pearl pulsations, resulting from the passage of atmospheric gravity waves generated in the vicinity of the earthquake epicentre.
ISSN:1432-0576
0992-7689
1432-0576
DOI:10.5194/angeo-31-1597-2013