source: production/onslow_2006/report/introduction.tex @ 3031

This report is being provided to the Fire and Emergency Services Authority
(FESA)
as part of the Collaborative Research Agreement with Geoscience Australia.
FESA recognises the potential vulnerability of the Western Australia
coastline to tsunamigenic earthquakes originating from 
the Sunda Arc subduction zone. There is
historic evidence of such events, \cite{CB:ausgeo}, 
and FESA has sought to assess
the relative risk of its urban and regional communities to the tsunami
threat and develop detailed response plans.

This report is the first in a series of studies to assess the relative
risk to the tsunami threat. The methods, assumptions and results of a
single tsunami source scenario is described for the Onslow area in the 
North West shelf region. 
Onslow has a population of around 800
is part of the Shire of Ashburton in the Pilbara region of Western Autralia
\footnote{http://www.pdc.wa.gov.au/region/political.htm}. Onslow supports
a variety of industries, including oil, gas, mining, cattle, fishing and tourism.

The return period of this particular scenario is unknown, however it
can be be classed as a plausible event. Future studies
will present a series of scenarios for a range of return events to 
assist FESA in developing appropriate plans for a range of event impacts.
The software tool, ANUGA, has been used to develop the inundation extent
and associated water height at various points in space and time.
ANUGA has been developed by GA and the Australian National University
(ANU) to solve the nonlinear shallow water
wave equation using the finite volume technique 
(described in \cite{ON:modsim}).
An advantage of this technique is that the cell resolution can be changed
according to areas of interest and that wetting and drying
is treated robustly as part of the numerical scheme. 
ANUGA is continually being developed and validated.
As such, the current results represent ongoing work
and may change in the future.

The following set of information is required input to undertake the tsunami
impact modelling and will be discussed in following sections.

\begin{itemize}
\item onshore and offshore data
\item initial condition
\item boundary condition
\end{itemize}

The inundation results for the Onslow area is described in section
\ref{sec:results}.