1 | This report has described the impact on Onslow from a tsunami |
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2 | generated by a Mw 9 earthquake on the Sunda Arc subduction zone |
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3 | occurring at Highest Astronomical Tide, Lowest Astronomical Tide |
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4 | and Mean Sea Level. |
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5 | As yet, there is no knowledge of the return period for this event. The |
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6 | modelling methodology, assumptions and data sources for the Onslow |
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7 | scenario have also been described. |
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8 | |
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9 | As shown in Section \ref{sec:data}, it is imperative |
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10 | that the best available data is used to increase confidence |
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11 | in the inundation maps. |
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12 | Given that the Highest Astronomical Tide contour |
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13 | line is further from the coast for the DTED data than the DLI data, we |
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14 | expect the inundation to extend further and thus be greater than |
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15 | that seen in Figure \ref{fig:MSL_max_inundation}. |
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16 | The impact modelling |
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17 | will result in significantly inflated structural and contents loss figures as well as |
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18 | numbers of people affected. |
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19 | These results strongly point to the need for the best |
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20 | available data so that more accurate predictions regarding the |
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21 | inundation can be made. |
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22 | An onshore grid resolution of the order |
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23 | of tens of metres is required, however, it is more important that the data |
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24 | are accurate (or at least well known). |
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25 | |
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26 | These scenarios will be revisited once the probabilistic models |
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27 | are complete so that a suite of tsunami impact assessments can be made. |
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28 | Future activities to support the impact studies on the North West Shelf |
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29 | include: |
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30 | |
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31 | \begin{itemize} |
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32 | \item Sourcing of data sets, |
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33 | \item Investigation of solution sensitivity to cell resolution, |
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34 | bathymetry and tsunami source uncertainties, |
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35 | \item Location of boundary for simulation study area, and |
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36 | \item Investigation of friction coefficients. |
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37 | \end{itemize} |
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38 | |
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39 | |
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