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| Titel |
Spectrum of the seismic-electromagnetic and acoustic waves caused by seismic and volcano activity |
| VerfasserIn |
S. Koshevaya, N. Makarets, V. Grimalsky, A. Kotsarenko, R. Pérez Enríquez |
| 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 ; 5, no. 2 ; Nr. 5, no. 2 (2005-02-02), S.203-209 |
| Datensatznummer |
250002331
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| Publikation (Nr.) |
 copernicus.org/nhess-5-203-2005.pdf |
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| Zusammenfassung |
| Modeling of the spectrum of the seismo-electromagnetic and acoustic waves,
caused by seismic and volcanic activity, has been done. This spectrum
includes the Electromagnetic Emission (EME, due to fracturing piezoelectrics
in rocks) and the Acoustic Emission (AE, caused by the excitation and the
nonlinear passage of acoustic waves through the Earth's crust, the
atmosphere, and the ionosphere). The investigated mechanism of the EME uses
the model of fracturing and the crack motion. For its analysis, we consider
a piezoelectric crystal under mechanical stresses, which cause the uniform
crack motion, and, consequently, in the vicinity of the moving crack also
cause non-stationary polarization currents. A possible spectrum of EME has
been estimated. The underground fractures produce Very Low (VLF) and
Extremely Low Frequency (ELF) acoustic waves, while the acoustic waves at
higher frequencies present high losses and, on the Earth's surface, they
are quite small and are not registered. The VLF acoustic wave is subject to
nonlinearity under passage through the lithosphere that leads to the
generation of higher harmonics and also frequency down-conversion, namely,
increasing the ELF acoustic component on the Earth's surface. In turn, a
nonlinear propagation of ELF acoustic wave in the atmosphere and the
ionosphere leads to emerging the ultra low frequency (ULF) acousto-gravity
waves in the ionosphere and possible local excitation of plasma waves. |
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