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| Titel |
How long are submarine landslides coupled to the water column? |
| VerfasserIn |
J. O'Shay, R. Weiss, C. E. Synolakis |
| 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 |
250070306
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| Zusammenfassung |
| Waves generated from submarine mass failure, come in second only to earthquakes as the
most frequent causes of tsunami waves. The gap however between the understanding of
earthquake generated waves and the generation of tsunami waves from submarine mass
failure (hereafter called submarine landslides) is quite large. A critical component of
shortening this gap is to understand the efficiency that submarine landslides have in
generating tsunamis. Unlike earthquake-induced tsunamis, where the deformation
at the free surface can be derived directly from the deformation of the seafloor,
submarine landslides exhibit a complex and nonlinear energy transfer from the
moving slide to the water column. Therefore the application of several empirical
formulae and equations derived from theory do not lead consistent results. For example
inverting the amplitude of the leading wave with such equations can result in a
scatter of the wave height up to six orders of magnitude. To derive more robust and
reliable estimates of leading-wave characteristics, the coupling between the slide body
and the water surface need to be investigated further to shed light on the energy
transfer.
We present results from parameters studies, carried out with the hydrocode iSALE. iSALE
has proven to be a reliable simulation tool for generation of large waves from subaerial and
submarine landslides. In order to shed more light on energy transfer from the slide body to
the water column, we focus, in here, on the duration of the energy transfer. In our modeling
the slide motion generates a trough with depth, s, which increases after the slide is
in motion, ds-dt > 0. Decoupling, tau, is then defined when ds-dt -¤ 0, and the
decoupling time, Ïd, as being reached when ds-dt = 0. A parameter study relating
the decoupling to mass, depth of submergence, and viscosity is conducted as an
initial step in elucidating the generation processes of submarine landslide-generated
tsunamis. |
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