Changeset 2800


Ignore:
Timestamp:
May 4, 2006, 5:03:08 PM (18 years ago)
Author:
sexton
Message:

report updates

Location:
production/scenario_reports/report_end_FY06
Files:
3 edited

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  • production/scenario_reports/report_end_FY06/data.tex

    r2797 r2800  
    1 The runup height and resulting inundation ashore is determined by
     1The calculated run-up height and resulting inundation ashore is determined by
    22the input topographic and bathymetric data, the forcing terms, the
    33initial and boundary conditions, as well as the cell resolution. It
    44would be ideal if the data adequately captures all complex features
    55of the underlying bathymetry and topography and that the cell
    6 resolution be commensurate with the underlying data. Errors in any
    7 of these areas will affect the accuracy of the final model result.
     6resolution be commensurate with the underlying data. Any limitations
     7in terms of resolution and accuracy in the data will introduce
     8errors to the inundation maps as well as the range of model approximations,
     9including the cell resolution.
    810
    911A number of sources have supplied data for these two studies. With
     
    1416(about 30 metres), produced from 1:50 000 contours, elevations and
    1517drainage. The Department of Land Information (DLI) has provided a
    16 20m DEM and orthophotography covering the NW Shelf. This data set is
    17 not bare earth and as a result, we have chosen to use the 30m DTED
    18 Level 2 data due to its bare earth thingo.
     1820m DEM and orthophotography covering the NW Shelf. As the 30m
     19DTED Level 2 data is bare earth we have chosen to use this as
     20the onshore data set.
    1921
    2022With respect to the offshore data, the Department of Planning and
     
    2628fairsheet data has also been utilised.
    2729
    28 The coastline has been generated from the DIGO DTED2 and modified
     30In summary,
     31
     32\begin{center}
     33\begin{tabular}{|l|l|}\hline
     34Data & Detail \\ \hline
     35DIGO DTED Level 2  & Onshore, 1 second $\approx$ 30m) \\ \hline
     36DLI & Onshore, 20m DEM and orthophotography \\
     37\hline DPI & Offshore, fairsheet data around Onslow \\
     38\hline Pt Hedland Port Authority \hspace{.3in} & Offshore,
     39digital multibeam survey
     40\\ \hline
     41\end{tabular}
     42\end{center}
     43
     44The coastline has been generated from the DIGO DTED Level 2 and modified
    2945using the aerial photography and the two detailed surveys provided
    30 by WA Department of Planning and Infrastructure. The extent of the
     46by WA Department of Planning and Infrastructure.
     47
     48\input{data_issues}
     49
     50The extent of the
    3151data used for the tsunami impact modelling can be seen in the
    3252following two figures.
     
    5171these studies.
    5272
    53 In summary,
    5473
    5574
    56 \begin{center}
    57 \begin{tabular}{|l|l|}\hline
    58 Data & Detail \\ \hline DIGO DTED Level 2  & Onshore, 1 second
    59 ($\approx$ 30m) \\ \hline DLI & Onshore, 20m DEM and
    60 orthophotography \\ \hline DPI & Offshore, fairsheet data around
    61 Onslow \\ \hline Pt Hedland Port Authority \hspace{.3in} & Offshore,
    62 digital multibeam survey
    63 \\ \hline
    64 \end{tabular}
    65 \end{center}
    6675
    67 
    68 \input{data_issues}
  • production/scenario_reports/report_end_FY06/introduction.tex

    r2797 r2800  
    33(FESA)
    44as part of the Collaborative Research Agreement with Geoscience Australia.
    5 The report describes the methods, assumptions and results of tsunami inundation
    6 scenarios for two areas in the North West shelf region of the West Australian
    7 coastline, namely Onslow and Pt Hedland.
     5FESA recognises the potential vulnerability of the Western Australia
     6coastline to tsunamigenic earthquakes originating from
     7the Sunda Arc subduction zone. There is
     8historic evidence of such events and FESA has sought to assess
     9the relative risk of its urban and regional communities to the tsunami
     10threat and develop detailed response plans.
    811
    9 Describe why this work is being done – exposure, vulnerability –
    10 understand impact and risk to tsunami hazard.
    11 
     12This report is the first in a series of studies to assess the relative
     13risk to the tsunami threat. The methods, assumptions and results of a
     14single tsunami source scenario is described for two areas in the
     15North West shelf region, namely Onslow and Pt Hedland. The return
     16period of this particular scenario is unknown, however it
     17can be be classed as a plausible event. Future studies
     18will present a series of scenarios for a range of return events to
     19assist FESA in developing appropriate plans for a range of event impacts.
    1220
    1321The software tool, ANUGA, has been used to develop the inundation extent
    1422and associated water height at various points in space and time.
    15 ANUGA has been developed by GA and ANU to solve the nonlinear shallow water
     23ANUGA has been developed by GA and the Australian National University
     24(ANU) to solve the nonlinear shallow water
    1625wave equation using the finite volume technique (described in [1]).
    1726An advantage of this technique is that the cell resolution can be changed
  • production/scenario_reports/report_end_FY06/tsunami_scenario.tex

    r2797 r2800  
    1 need to say something about the event, i.e. Mw 8.5 event initiated
    2 along the Java Trench (get from David)
     1The tsunamigenic event used for this study is one used
     2to develop the preliminary tsunami hazard assessment which
     3was delivered to FESA in September 2005 (ref Burbidge, D. and
     4Cummins, P. 2005). In that assessment, a suite of
     5tsunami were evenly spaced along the Sunda Arc subduction zone and there
     6was no consideration of likelihood. Other sources were not considered, such
     7as intra-plate earthquakes near the WA coast, volcanoes, landslides
     8or asteroids. The preliminary assessment argued
     9that the maximum magnitude of earthquakes off Java is at least 8.5 and
     10could potentially be as high as 9.
     11
     12Current studies underway in GA are building probabilistic
     13models to develop a more complete tsunami hazard assessment
     14for the Sunda Arc subduction zone. (This is
     15due for completion in late 2006.) In the preliminary assessment for
     16example, it was argued that while Mw 7 and 8 earthquakes are expected
     17to occur with a greater frequency, they are likely to pose a comparatively
     18low and localised hazard to WA.
     19
     20FESA are interested in the ``most frequent worst case scenario''. Whilst
     21we cannot determine what that event may be, the Mw 8.5 event provides
     22a plausible worst case scenario.
     23
     24The following figure is taken from the preliminary assessment and
     25shows the maximum wave height up to the 50m contour for a Mw 8.5 event off
     26the coast of Java. It is this event which provides the source to the
     27inundation modelling presented in the following section.
     28
     29
    330
    431\begin{figure}[hbt]
    532
    6   %\centerline{ \includegraphics[width=75mm, height=75mm]{figures/.eps}}
     33  \centerline{ \includegraphics[width=75mm, height=75mm]{mw85.jpg}}
    734
    8   \caption{Source zones of influence}
    9   \label{fig:source}
     35  \caption{Maximum wave height (in cms) for a Mw 8.5 event off the
     36coast of Java}
     37  \label{fig:mw85}
    1038\end{figure}
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