Journal cover Journal topic
Natural Hazards and Earth System Sciences An interactive open-access journal of the European Geosciences Union
Nat. Hazards Earth Syst. Sci., 15, 1763-1784, 2015
https://doi.org/10.5194/nhess-15-1763-2015
© Author(s) 2015. This work is distributed under
the Creative Commons Attribution 3.0 License.
Research article
11 Aug 2015
Scenario-based numerical modelling and the palaeo-historic record of tsunamis in Wallis and Futuna, Southwest Pacific
G. Lamarche1, S. Popinet1,a, B. Pelletier2, J. Mountjoy1, J. Goff3, S. Delaux1,b, and J. Bind4 1National Institute of Water {&} Atmospheric (NIWA) Research, 301 Evans Bay Parade, Wellington 6021, New Zealand
2Institut de Recherche pour le Développement, BP A5, Nouméa, New Caledonia
3School of Biological, Earth and Environmental Sciences, UNSW Australia, Sydney 2052, Australia
4NIWA, 10 Kyle Street, Christchurch 8011, New Zealand
anow at: CNRS – Université Pierre et Marie Curie Paris 6, Institut Jean Le Rond d'Alembert, 75005 Paris, France
bnow at: MetOcean Solutions Ltd. 5 Wainui Rd, Raglan 3225, New Zealand
Abstract. We investigated the tsunami hazard in the remote French territory of Wallis and Futuna, Southwest Pacific, using the Gerris flow solver to produce numerical models of tsunami generation, propagation and inundation. Wallis consists of the inhabited volcanic island of Uvéa that is surrounded by a lagoon delimited by a barrier reef. Futuna and the island of Alofi form the Horn Archipelago located ca. 240 km east of Wallis. They are surrounded by a narrow fringing reef. Futuna and Alofi emerge from the North Fiji Transform Fault that marks the seismically active Pacific-Australia plate boundary. We generated 15 tsunami scenarios. For each, we calculated maximum wave elevation (MWE), inundation distance and expected time of arrival (ETA). The tsunami sources were local, regional and distant earthquake faults located along the Pacific Rim. In Wallis, the outer reef may experience 6.8 m-high MWE. Uvéa is protected by the barrier reef and the lagoon, but inundation depths of 2–3 m occur in several coastal areas. In Futuna, flow depths exceeding 2 m are modelled in several populated areas, and have been confirmed by a post-September 2009 South Pacific tsunami survey. The channel between the islands of Futuna and Alofi amplified the 2009 tsunami, which resulted in inundation distance of almost 100 m and MWE of 4.4 m. This first ever tsunami hazard modelling study of Wallis and Futuna compares well with palaeotsunamis recognised on both islands and observation of the impact of the 2009 South Pacific tsunami. The study provides evidence for the mitigating effect of barrier and fringing reefs from tsunamis.

Citation: Lamarche, G., Popinet, S., Pelletier, B., Mountjoy, J., Goff, J., Delaux, S., and Bind, J.: Scenario-based numerical modelling and the palaeo-historic record of tsunamis in Wallis and Futuna, Southwest Pacific, Nat. Hazards Earth Syst. Sci., 15, 1763-1784, https://doi.org/10.5194/nhess-15-1763-2015, 2015.
Publications Copernicus
Download
Short summary
The research investigates the tsunami hazard in the remote French territory of Wallis and Futuna, Southwest Pacific, using numerical computer modelling of tsunami generation, propagation and inundation. Wallis consists of the inhabited island of Uvéa that is surrounded by a lagoon delimited by a barrier reef, whereas Futuna and the island of Alofi form the Horn Archipelago located ca. 240 km east. Futuna and Alofi are surrounded by a narrow fringing reef and emerge from the North Fiji Transform.
The research investigates the tsunami hazard in the remote French territory of Wallis and...
Share