This report has described the impact to Onslow from a tsunami generated by a Mw 9 earthquake on the Sunda Arc subduction zone occurring at Mean Sea Level. There is no knowledge of the return period for this event. The modelling methodology, assumptions and data sources which are required to determine the impact to Onslow have also been described. As discussed in Section \ref{sec:issues}, there are issues with the underlying data set which may have vertical inaccuracies of approximately 1-2m. As a result, these results should be considered preliminary. These scenarios will be revisited once the probabilistic models are complete so that a suite of tsunami impact assessments can be made. It is therefore imperative that suitably accurate onshore data be made available to raise confidence in the impact assessments. Future activities to support the impact studies on the North West Shelf include: \begin{itemize} \item Sourcing of data sets \item Investigation of solution sensitivity to cell resolution, bathymetry and tsunami source uncertainties \item Location of boundary for simulation study area \item Investigation of friction coefficients \end{itemize}