On Modelling 2006, 2007 Simushir Tsunamis in the Central Kuril Region

Ivanova A. A., Kulikov E. A., Fain I. V.

The subject of this study is to estimate how the quality of bottom bathymetry data effects on the capability of the numerical models to adequately reproduce the distribution of the maximum heights of tsunami waves along the coast. Numerical experiments have been carried out for the Simushir tsunamis of November 15, 2006 and January 13, 2007 in the Central Kuril region. It is shown that widely used bathymetry data bases, such as GEBCO, do not provide the required accuracy and resolution of digital bathymetry charts. Here we have used various data sources, including GEBCO in the deep ocean region and data from the GUNIO on the shelf and in the shallow waters. It is shown that the calculations performed for grids with a resolution of 30 arc seconds provide only a qualitative estimate of the distribution of tsunami heights along the coast. At the same time, a quantitative coincidence of the simulation results and the observational data can be obtained only for grids with a spatial resolution of 10 arc seconds or better. The maximum tsunami heights were observed along the coast of Isle Matua, which is confirmed by the model calculations. Detailed studies have shown that the extreme tsunami heights and current velocities are observed in the Dvoynaia Bay (Matua Island) and are associated with the occurrence of eigenmodes oscillations in the bay.

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