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| Titel |
The shock-acoustic waves generated by earthquakes |
| VerfasserIn |
E. L. Afraimovich, N. P. Perevalova, A. V. Plotnikov, A. M. Uralov |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
0992-7689
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| Digitales Dokument |
URL |
| Erschienen |
In: Annales Geophysicae ; 19, no. 4 ; Nr. 19, no. 4, S.395-409 |
| Datensatznummer |
250014234
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| Publikation (Nr.) |
 copernicus.org/angeo-19-395-2001.pdf |
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| Zusammenfassung |
We
investigate the form and dynamics of shock-acoustic waves
generated by earthquakes. We use the method for
detecting and locating the sources of ionospheric impulsive disturbances,
based on using data from a global network of
receivers of the GPS navigation system, and require no a
priori information about the place and time of the associated effects.
The practical implementation of the method is illustrated
by a case study of earthquake effects in Turkey (17
August and 12 November 1999), in Southern Sumatra (4 June
2000), and off the coast of Central America (13 January 2001).
It was found that in all instances the time period of
the ionospheric response is 180–390 s, and the amplitude exceeds,
by a factor of two as a minimum, the standard deviation of
background fluctuations in total electron content in
this range of periods under quiet and moderate geomagnetic conditions.
The elevation of the wave vector varies through
a range of 20–44°, and the phase velocity (1100–1300
m/s) approaches the sound velocity at the heights of the ionospheric
F-region maximum. The calculated (by neglecting refraction
corrections) location of the source roughly corresponds to
the earthquake epicenter. Our data are consistent with
the present views that shock-acoustic waves are caused by
a piston-like movement of the Earth’s surface in the zone of
an earthquake epicenter.
Key words. Ionosphere
(ionospheric disturbances; wave propagation)
– Radio science (ionospheric propagation) |
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