Use of numerical models to inform distant-source tsunami warnings

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Power, W.L.; Gale, N.H.; Lukovic, B.; Gledhill, K.R.; Clitheroe, G.; Berryman, K.R.; Prasetya, G. 2010 Use of numerical models to inform distant-source tsunami warnings Lower Hutt, N.Z.: GNS Science. GNS Science report 2010/11 22 p.

Abstract: A comprehensive set of tsunami propagation models has been calculated for distant-source tsunami scenarios caused by earthquakes of magnitudes 8.7, 9.0 and 9.3 in the source regions. Information on the maximum wave-heights reached in each scenario has been expressed in terms of the maximum water level attained within ~40km sections of New Zealand coast. This maximum water level information has been put into the form of a threat level for each section of coast. By using the maximum water-level anywhere within the 40km zone as an estimate of the threat-level a degree of conservatism is incorporated. Comparison with historical records suggests a generally acceptable match, with a tendency towards cautious predictions. Some outliers are present, probably due to small scale bathymetry features not well represented by our model, and these emphasise the value of other sources of information, such as historical databases, when preparing a tsunami forecast. The two main areas for future improvement over the current threat-level modelling are: Incorporation of the results of DART buoy measurements into the scaling of source scenarios. This is important because the magnitude Mw is not the only source parameter that determines the size of tsunami, and because Mw is often poorly estimated in the immediate aftermath of large (Mw >~ 9.0) earthquakes; Explicit modelling of tsunami propagation into the near-shore (