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| Titel |
Anomalous Schumann resonance observed in China, possibly associated with Honshu, Japan Earthquake |
| VerfasserIn |
X. Y. Ouyang, X. M. Zhang, X. H. Shen, Y. Q. Miao |
| Konferenz |
EGU General Assembly 2012
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 14 (2012) |
| Datensatznummer |
250061423
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| Zusammenfassung |
| Schumann resonance (hereafter SR) occurs in the cavity between the Earth and the
ionosphere, and it is originated by the global lightning activities [1]. Some recent publications
showed that anomalous SR phenomena may occur before major earthquakes [2-4].
Considering good prospects for the application of SR in Earthquake monitoring, we have
established four observatories in Yunnan province, a region with frequent seismicity in the
southwest of China. Our instruments can provide three components of magnetic field in 0-30
Hz, including BNS(North-South component), BEW(East-West component) and BV (Vertical
component). The sample frequency is 100 Hz. In this research, we use high quality data
recorded at Yongsheng observatory (geographic coordinates: 26.7Ë N, 100.77Ë
E) to analyze SR phenomena to find out anomalous effects possibly related with
the Ms9.0 Earthquake (epicenter: 38.297Ë N, 142.372Ë E) near the east coast of
Honshu, Japan on 11 March 2011. We select the data 15 days before and after the
earthquake.
SR in BNS and SR in BEWappear different in background characteristics. Frequencies of
four SR modes in BNSare generally higher than that in BEW. Amplitude of SR in BNSis
strong at around 05:00 LT, 15:00 LT and 23:00 LT of the day, while amplitude of SR in BEW
is just intense around 16:00 LT, corresponding to about 08:00 UT. Because American,
African and Asian thunderstorm centers play their dominant roles respectively in the intervals
of 21:00UT±1h, 15:00UT±1h and 08:00UT±1h [1, 3], we can see that SR in BEWis most
sensitive to signals from Asian center and SR in BNS is in good response to three
centers.
SR in BNS and SR in BEW have presented different features in the aspect of anomalous
effects related with earthquakes. BEW component gives us a clear picture of anomalous SR
phenomena, which are characterized by increase in amplitude of four SR modes and
increase in frequency at first SR mode several days before the earthquake. The
amplitude of four SR modes began to increase four days before Honshu earthquake (7th
March). And this continued to the day of the earthquake (11th March). Then it fell to
the usual intensity after the earthquake (12th March). The frequency at first SR
mode in BEW unconventionally exceeded the first mode frequency in BNS with an
enhancement of 0.7 Hz on 8th and 9th March. We did not find similar anomalous effects
in BNS. The anomalous effects in BEW may be caused by interference between
direct path from Asian center to the observatory and disturbed path scattered by
the perturbation in the ionosphere over Honshu. More detailed analysis is going
on.
1. Nickolaenko A P and Hayakawa M, Resonances in the Earth-ionosphere cavity. 2002:
Kluwer Academic Pub.
2. Hayakawa M, Ohta K, Nickolaenko A P, et al. Anomalous effect in Schumann
resonance phenomena observed in Japan, possibly associated with the Chi-chi earthquake in
Taiwan. Annales geophysicae,2005. pp. 1335-1346.
3. Hayakawa M, Nickolaenko A P, Sekiguchi M, et al., Anomalous ELF phenomena in
the Schumann resonance band as observed at Moshiri (Japan) in possible association with an
earthquake in Taiwan. Nat. Hazards Earth Syst. Sci, 2008. 8(6): p. 1309–1316.
4. Ohta K, Izutsu J, and Hayakawa M, Anomalous excitation of Schumann resonances
and additional anomalous resonances before the 2004 Mid-Niigata prefecture earthquake and
the 2007 Noto Hantou Earthquake. Physics and Chemistry of the Earth, Parts A/B/C, 2009.
34(6-7): p. 441-448. |
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