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Titel |
Hydro-seismic-acoustical monitoring of submarine earthquakes preparation: observations and analysis |
VerfasserIn |
E. V. Sasorova, B. W. Levin, V. E. Morozov |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
1680-7340
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Digitales Dokument |
URL |
Erschienen |
In: 2nd EGU Alexander von Humboldt Conference "The role of Geophysics in Natural Disaster Prevention" ; Nr. 14 (2008-01-02), S.99-104 |
Datensatznummer |
250012089
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Publikation (Nr.) |
copernicus.org/adgeo-14-99-2008.pdf |
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Zusammenfassung |
The results of laboratory experiments on rock sample destruction and the
observation data obtained from several series of the hydro-acoustic
observations in which the researchers succeeded to register the signals in
the critical stage of the earthquake (EQ) preparation were compared.
According to theoretical research (Alekseev et al., 2001) two distinct
dilatant zones occur in the EQ preparation stage. The first one is located
around the source and the second one represents the near-surface dilatant
zone. Only high-frequency seismic-acoustic signals (SAS) radiated from the
near-surface dilatant zone do not attenuate completely on the passage
through a solid medium. Parameters of the SAS such as the source depth under
the ocean floor, frequency maximum and the signal power level were
estimated. It was shown that the critical stage of the EQ preparation
continues several tens hours and this process has a hierarchical nature. At
first the micro-ruptures are formed over a large area. Then the high
frequency radiation begins to decrease, the SAS emission area begins to
shrink and the micro-earthquakes occur in the area surrounding the
epicenter. The obtained results are in close agreement with the theoretical
conception about the evolution of the SAS in the surface dilatant zone and
with the results of laboratory experiments. |
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