The tsunamigenic event used for this study is one used
to develop the preliminary tsunami hazard assessment which 
was delivered to FESA in September 2005 (ref Burbidge, D. and
Cummins, P. 2005). In that assessment, a suite of
tsunami were evenly spaced along the Sunda Arc subduction zone and there
was no consideration of likelihood. Other sources were not considered, such
as intra-plate earthquakes near the WA coast, volcanoes, landslides
or asteroids. The preliminary assessment argued
that the maximum magnitude of earthquakes off Java is at least 8.5 and
could potentially be as high as 9.

Current studies underway in GA are building probabilistic
models to develop a more complete tsunami hazard assessment
for the Sunda Arc subduction zone. (This is
due for completion in late 2006.) In the preliminary assessment for
example, it was argued that while Mw 7 and 8 earthquakes are expected
to occur with a greater frequency, they are likely to pose a comparatively
low and localised hazard to WA. 

FESA are interested in the ``most frequent worst case scenario''. Whilst
we cannot determine what that event may be, the Mw 9 event provides
a plausible worst case scenario. 

The following figure is taken from the preliminary assessment and
shows the maximum wave height up to the 50m contour for a Mw 9 event off
the coast of Java. It is this event which provides the source to the
inundation modelling presented in the following section.



\begin{figure}[hbt]

  \centerline{ \includegraphics[width=75mm, height=75mm]{mw9.jpg}}

  \caption{Maximum wave height (in cms) for a Mw 9 event off the 
coast of Java}
  \label{fig:mw9}
\end{figure}