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| Titel |
Numerical modelling of the 1979 Nice landslide-generated tsunami |
| VerfasserIn |
Claire Donnadieu, Hélène Hébert, Ricardo Silva Jacinto, Pauline Meyniel |
| Konferenz |
EGU General Assembly 2010
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250040249
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| Zusammenfassung |
| On the 16th October 1979, a part of the building site of the Nice airport extension intended to
become the new Nice harbour collapsed into the Mediterranean Sea during landfilling
operations. This submarine slide of initial volume of 10 millions of m3, located near the
seashore, generated a turbidity current that propagated along the Var canyon. A few minutes
after the landslide, a small tsunami was observed by several witnesses 60 km along the
coast, called "Baie des Anges". The most destructive effect occurred near the city of
Antibes, 10 km away from the source, which was inundated and where one person
died.
In the framework of the RATCOM (Réseau d’Alertes aux Tsunamis et COtiers en
Méditerranée) project, this event is numerically simulated with the goal of establishing the
appropriate monitoring network which could have detected this event by means of gauges
located offshore. Two additional scenarios of hypothetical sources recently identified by
IFREMER in the same area are also computed : a small volume of 0.6 millions of m3, close
to the 1979 breakdown area, and a larger one of 7 millions of m3, located easterly. A very
accurate bathymetric map of the area provided by IFREMER and completed by SHOM data
near the coast is used.
The dynamics of the slide and the water waves generated are both computed in the shallow
water approximation, considering the interaction between the mass of sediments constituting
the slide and the water. The landslide is modelled as a Newtonian homogeneous viscous flow
sliding under gravity along the bathymetry and the tsunami model is initialized by
taking into account the bottom deformation induced by the slide. Incorporation of
water in the mass of sediments at the interface between landslide and water can be
considered. The equations are solved by a finite difference method based on shock
capturing.
Numerical results of tsunami waves amplitudes generated by the landslide during the
propagation and along the coast are compared to witnesses observations and available tide
gauges signals. Local effects in front of the Nice airport are well reproduced with consistent
wave polarity, arrival time and amplitude. However, in the far field, results are not
in agreement with observations, in particular, simulated wave amplitudes are too
small to inundate Antibes city. Water entrainment inside the slide increases these
amplitudes. Further developments will involve better refinement around Antibes
city. |
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