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| Titel |
Quakes and tsunamis detected by GOCE |
| VerfasserIn |
Raphael F. Garcia, Eelco Doornbos, Sean Bruinsma, Hélène Hébert |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250096243
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| Publikation (Nr.) |
 EGU/EGU2014-11737.pdf |
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| Zusammenfassung |
| The aerodynamic accelerations measured by GOCE are used to calculate air density
variations and air velocity estimates along GOCE orbit track. The detection of infrasonic
waves generated by seismic surface waves and gravity waves generated by tsunamis are
presented for earthquakes and tsunamis generated by the great Tohoku quake (11/03/2011).
For the seismic/infrasonic waves, a wave propagation modelling is presented and
synthetic data are compared to GOCE measurements. The travel time and amplitude
discrepancies are discussed in terms of lateral velocity variations in the solid Earth and the
atmosphere. For the tsunami/gravity waves, a plane wave analysis is performed and
relations between vertical velocity, cross-track velocity and density variations are
deduced. From theoretical relations between air density, and vertical and horizontal
velocities inside the gravity wave, we demonstrate that the measured perturbations are
consistent with a gravity wave generated by the tsunami, and provide a way to
estimate the propagation azimuth of the gravity wave. By using these relations, an
indicator of gravity wave presence is constructed. It will allow to scan the GOCE
data set to search for gravity wave crossings. This study demonstrates that very
low earth orbit spacecraft with high-resolution accelerometers are able to detect
atmospheric waves generated by the tectonic activity. Such spacecraft may supply
additional data to tsunami alert systems in order to validate some tsunami alerts. |
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