摘要:On 29 September 2009 at 17:48:11 UTC, a large earthquake of magnitude 8 struck
off-shore of the Samoa Islands and generated a large tsunami that destroyed several
villages and caused more than 160 fatalities. This report first presents the characteristics
of the earthquake and discusses the best estimations for the fault parameters, which are
the necessary input data for the hydrodynamic tsunami calculations. Then, the
assessment of the near-real time systems invoked by the Global Disasters Alert and
Coordination System (GDACS)1 and the post-event calculations are performed, making
comparisons with the observed tidal measurements and post-event survey. It was found
that the most severely damaged locations are the Southern section of the Western Samoa
Islands, Tutuila Isl in American Samoa and Niuatoputapu Isle in Tonga. This is in
agreement with the locations indicated by the Red Cross as the most affected and with
the results of the post-tsunami surveys. Furthermore, an attempt was made to map the
inundation events using more detailed digital elevation models (DEM) and
hydrodynamic modelling with good results. The flooded areas for which we had satellite
images and post-tsunami surveys confirm the inundated areas identified correctly by the
hydrodynamic model. Indications are given on the DEM grid size needed for the
different simulations.
关键词:GDACS; 2009 Samoa tsunami; tsunami propagation and inundation;early warning system; fault model; DEM assessment