source: production/onslow_2006/report/tsunami_scenario.tex @ 3171

The tsunamigenic event used for this study was developed for a 
preliminary tsunami hazard assessment study delivered to FESA in September 2005,
\cite{BC:FESA}. In that assessment, a suite of Mw 9 earthquakes
were evenly spaced along the Sunda Arc subduction zone and there
was no consideration of the likelihood of each event. 
Other sources were not considered, such
as intra-plate earthquakes near the WA coast, volcanoes, landslides
or asteroids as they are known to be less likely. 
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,
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 than Mw 9 events, 
they are likely to pose a comparatively low and more localised hazard to WA. 

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

Figure \ref{fig:mw9} shows the maximum wave height at the 50m contour 
for a Mw 9 event off
the coast of Java. It is this event which provides the source and
boundary condition to the
inundation model presented in this report. Description of the boundary 
condition particular to the Onslow study area 
follows in Section \ref{sec:anuga}.


\begin{figure}[hbt]

  \centerline{ \includegraphics[width=100mm, height=75mm]
{../report_figures/mw9.jpg}}

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