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| Titel |
Fractal analysis of the ULF geomagnetic data obtained at Izu Peninsula, Japan in relation to the nearby earthquake swarm of June–August 2000 |
| VerfasserIn |
K. Gotoh, M. Hayakawa, N. Smirnova |
| 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.229-236 |
| Datensatznummer |
250000681
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| Publikation (Nr.) |
 copernicus.org/nhess-3-229-2003.pdf |
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| Zusammenfassung |
| In our recent papers
we applied fractal methods to extract the earthquake precursory signatures
from scaling characteristics of the ULF geomagnetic data, obtained in a
seismic active region of Guam Island during the large earthquake of 8
August 1993. We found specific dynamics of their fractal characteristics
(spectral exponents and fractal dimensions) before the earthquake:
appearance of the flicker-noise signatures and increase of the time series
fractal dimension. Here we analyze ULF geomagnetic data obtained in a
seismic active region of Izu Peninsula, Japan during a swarm of the strong
nearby earthquakes of June–August 2000 and compare the results obtained
in both regions. We apply the same methodology of data processing using
the FFT procedure, Higuchi method and Burlaga-Klein approach to calculate
the spectral exponents and fractal dimensions of the ULF time series. We
found the common features and specific peculiarities in the behavior of
fractal characteristics of the ULF time series before Izu and Guam
earthquakes. As a common feature, we obtained the same increase of the ULF
time series fractal dimension before the earthquakes, and as specific
peculiarity – this increase appears to be sharp for Izu earthquake in
comparison with gradual increase of the ULF time series fractal dimension
for Guam earthquake. The results obtained in both regions are discussed on
the basis of the SOC (self-organized criticality) concept taking into
account the differences in the depths of the earthquake focuses. On the
basis of the peculiarities revealed, we advance methodology for extraction
of the earthquake precursory signatures. As an adjacent step, we suggest
the combined analysis of the ULF time series in the parametric space
polarization ratio – fractal dimension. We reason also upon the
advantage of the multifractal approach with respect to the mono-fractal
analysis for study of the earthquake preparation dynamics. |
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