Adaptive modelling of long-distance wave propagation and fine-scale flooding during the Tohoku tsunami
Résumé
The 11th March 2011 Tohoku tsunami is simulated using the quadtree-adaptive Saint-
Venant solver implemented within the Gerris Flow Solver. The spatial resolution is
adapted dynamically from 250 metres in flooded areas up to 250 km for the areas at rest.
Wave fronts are tracked at a resolution of 1.8 km in deep water. The simulation domain
extends over 73 of both latitude and longitude and covers a significant part of the northwest
Pacific. The initial wave elevation is obtained from a source model derived using
seismic data only. Accurate long-distance wave prediction is demonstrated through comparison
with DART buoys timeseries and GLOSS tide gauges records. The model also
accurately predicts fine-scale flooding compared to both satellite and survey data. Adaptive
mesh refinement leads to orders-of-magnitude gains in computational efficiency compared
to non-adaptive methods. The study confirms that consistent source models for
tsunami initiation can be obtained from seismic data only. However, while the observed
extreme wave elevations are reproduced by the model, they are located further south than
in the surveyed data. Comparisons with inshore wave buoys data indicate that this may be
due to an incomplete understanding of the local wave generation mechanisms.
Domaines
Océanographie
Origine : Fichiers produits par l'(les) auteur(s)
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