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anuga_work/publications/boxing_day_validation_2008/patong_validation.tex
r6590 r6593 1 1 \documentclass[a4paper]{article} 2 \usepackage{modsim07}3 2 \usepackage{graphicx} 4 3 \usepackage{hyperref} 5 6 %================Start of Document================ 7 \ begin{document}4 \usepackage{amsfonts} 5 \usepackage{url} % for URLs and DOIs 6 \newcommand{\doi}[1]{\url{http://dx.doi.org/#1}} 8 7 9 8 %----------title-------------% … … 14 13 % FIXME(Ole): The 'ands' appear in the text, they shouldn't 15 14 \author{J.D.~Jakeman$^1$~~and~~O.~Nielsen$^2$~~and~~R.~Mleczko$^2$~~and~~K.~VanPutten$^2$~~and~~S.G~Roberts$^1$} 16 17 %------Affiliation---------- 18 \institute{$^1$The Australian National University, Canberra, Australia \\ 19 $^2$Geoscience Australia, Canberra, Australia\\ 20 Email: \href{mailto:jakeman@maths.anu.edu.au}{john.jakeman@anu.edu.au}} 21 \keywords{ANUGA, Finite Volume Method, Natural Hazards, Indian Ocean Tsunami, Inundation, Thailand, Phuket, Patong Bay, Post Tsunami Runup Survey, Bathymetry, Model Verification, Shallow Water Wave Equations} 22 15 \author{J.~D. Jakeman\thanks{The Australian National University, Canberra, \textsc{Australia}. 16 \protect\url{mailto:john.jakeman@anu.edu.au}} 17 \and O.Nielsen\thanks{Geoscience Australia, Canberra, \textsc{Australia}} 18 \and R. Mleczko\footnotemark[2] 19 \and K. VanPutten\footnotemark[2] 20 \and S.~G Roberts\footnotemark[1] 21 } 22 23 %================Start of Document================ 24 \begin{document} 23 25 \maketitle 24 25 26 %------Abstract-------------- 26 27 \begin{abstract} 27 28 28 29 \end{abstract} 29 %======================Section 1================= 30 31 \tableofcontents 32 %================Section=========================== 30 33 31 34 \section{Introduction} 32 Tsunami are a potential hazard to coastal communities all over the world. A number of recent large events have increased community and scientific awareness of the need for effective tsunami hazard mitigation. Tsunami modelling is major component of hazard mitigation, which involves detection, forecasting, and emergency preparedness (Synolakis {\it et al.} 2005). Accurate models can be used to provide information that increases the effectiveness of action undertaken before the event to minimise damage (early warning systems, breakwalls etc.) and protocols put in place to be followed when the flood waters subside. 33 34 Several approaches are currently used to model tsunami propagation and inundation. These methods differ in both the formulation used to describe the evolution of the tsunami and the numerical methods used to solve the governing equations. The shallow water wave equations, linearised shallow water wave equations, and Boussinesq-type equations are commonly accepted descriptions of flow. The nonlinear nature of these equations, the highly variable nature of the phenomena that they describe and the complex reality of the geometry they operate in necessitate the use of numerical models. These models are typically used to predict quantities such as arrival times, wave speeds and heights and inundation extents which are used to develop efficient hazard mitigation plans. Inaccuracies in model prediction can result in inappropriate evacuation plans and town zoning which may result in loss of life and large financial losses. Consequently tsunami models must undergo sufficient testing to increase scientific and community confidence in the model predictions. 35 36 Complete confidence in a model of a physical system cannot be established. A model only be shown not to fail for a specific experiment (FIXME - fiddle with this sentence). However, the utility of a model can be assessed through a process of validation and verification. Validation assesses the accuracy of the numerical method used to solve the governing equations and verification is used to investigate whether the model adequately represents the physical system (\cite{XXX}). %Verification must be used to reduce numerical error before validation is used to assess model structure. In some situations it may be possible to increase the numerical accuracy of a model and produce a worse fit of the observed data. 37 38 The sources of data used to validate and verify a model can be separated into three main categories; analytical solutions, scale experiments and field measurements. Analytical solutions of the governing equations of a model, if available, provide the best means of validating a numerical hydrodynamic model. 39 (FIXME: CAN WE GET RID OF THIS: The solutions provide spatially and temporally distributed values of important observables that can be compared against modelled results). However analytical solutions to the governing equations are frequently limited to a small set of idealised examples that do not completely capture the more complex behaviour of 'real' events. Scale experiments, typically in the form of wave-tank experiments provide a much more realistic source of data that better captures the complex dynamics of natural tsunami, whilst allowing control of the event and much easier and accurate measurement of the tsunami properties. However comparison of numerical predictions with field data provides one of the most stringent test of model veracity. The use of field data increases the generality and significance of conclusions made regarding model utility. However the use of field data also significantly increase the uncertainty of the validation experiment that may constrain the ability to make unequivocal statements~\cite{lane94}. 40 41 Currently the extent of tsunami related field data is limited. The cost of tsunami monitoring programs and bathymetry and topography surveys prohibits the collection of data in many of the regions in which tsunamis pose greatest threat. The resulting lack of data has limited the number of field data sets available to validate tsunami models, particularly those modelling tsunami inundation. Synolakis et. al~\cite{synolakis07} have developed a set of standards, criteria and procedures for evaluating numerical models of tsunami. They propose three analytical solutions to help identify the validity of a model and five scale comparisons (wave-tank benchmarks) and two field events to assess model veracity. The two field data benchmarks are very useful but only capture a small subset of possible tsunami behaviours (FIXME: What?) and only one of the benchmarks can be used to validate tsunami inundation (FIXME: Why?). The type and size of a tsunami source, propagation extent, and local bathymetry and topography all affect the energy, waveform and subsequent inundation of a tsunami. Consequently additional field data benchmarks that further capture the variability and sensitivity of the real world system would be useful to allow model developers verify their models and subsequently use their models with greater confidence. 42 43 In this paper we develop a field data benchmark to be used in conjunction with the other tests proposed by Synolakis et al. to validate and verify tsunami inundation. The benchmark is constructed from data collected around Patong Bay, Thailand immediately following the 2004 Indian Ocean tsunami. This area was chosen because the authors were able to obtain high resolution bathymetry and topography data in this area and an inundation map generated from a survey performed in the aftermath of the tsunami. A description of this data is give in Section~\ref{sec:data}. 44 45 An associated aim of this paper is to illustrate the use of this new benchmark to validate an operational tsunami model called ANUGA (see Secion~\ref{sec:veri_procedure}). The specific intention is to test the ability of ANUGA to reproduce the inundation survey of maximum runup. ANUGA is a hydrodynamic modelling tool used to simulate the tsunami propagation and run rain-induced floods. 46 47 %=================Section===================== 48 49 \section{Indian Ocean tsunami of 24th December 2004} 50 The devastation caused by the 2004 Indian Ocean tsunami has heightened community, scientific and governmental interest in tsunami and in doing so has provided a unique opportunity for further validation of tsunami models. Data sets from seismometers, tide gauges, GPS stations, a few satellite overpasses, subsequent coastal field surveys of run-up and flooding and measurements from ship-based expeditions, have now been made available (Vigny {\it et al.} 2005, Amnon {\it et al.} 2005, Kawata {\it et al.} 2005, and Liu {\it et al.} 2005)\nocite{vigny05,amnon05,kawata05,liu05}. A number of studies have utilised this data to calibrate models of the tsunami source\cite{grilli07} , match tide gauge recordings\cite{}, maximum wave heights~\cite{asavanant08} and runup locations~\cite{ioualalen07}. We propose to use this event as an additional field-data benchmark for verification of tsunami models. This event captures certain tsunami behaviours that are not present in the benchmarks proposed by Synolakis et.\ al~\cite{synolakis07}. FIXME: What kind of behaviours??? 35 Tsunami are a potential hazard to coastal communities all over the world. A number of recent large events have increased community and scientific awareness of the need for effective tsunami hazard mitigation. Tsunami modelling is major component of hazard mitigation, which involves detection, forecasting, and emergency preparedness~\cite{synolakis05}. Accurate models can be used to provide information that increases the effectiveness of action undertaken before the event to minimise damage (early warning systems, breakwalls etc.) and protocols put in place to be followed when the flood waters subside. 36 37 Several approaches are currently used to model tsunami propagation and inundation. These methods differ in both the formulation used to describe the evolution of the tsunami and the numerical methods used to solve the governing equations. The shallow water wave equations, linearised shallow water wave equations, and Boussinesq-type equations are frequently used to simulate tsunami propagation. The nonlinear nature of these equations, the highly variable nature of the phenomena that they describe and the complex reality of the geometry they operate in necessitate the use of numerical models. These models are typically used to predict quantities such as arrival times, wave speeds and heights and inundation extents which are used to develop efficient hazard mitigation plans. Inaccuracies in model prediction can result in inappropriate evacuation plans and town zoning which may result in loss of life and large financial losses. Consequently tsunami models must undergo sufficient testing to increase scientific and community confidence in the model predictions. 38 39 Complete confidence in a model of a physical system frequently in general cannot be established. One can only hope to state under what conditions the model hypothesis holds true. Specifically the utility of a model can be assessed through a process of validation and verification. Validation assesses the accuracy of the numerical method used to solve the governing equations and verification is used to investigate whether the model adequately represents the physical system. Together these processes can be used to establish the likelihood that that a model is a legitimate hypothesis~\cite{bates01}. 40 41 The sources of data used to validate and verify a model can be separated into three main categories; analytical solutions, scale experiments and field measurements. Analytical solutions of the governing equations of a model, if available, provide the best means of validating a numerical hydrodynamic model. However analytical solutions to the governing equations are frequently limited to a small set of idealised examples that do not completely capture the more complex behaviour of `real' events. Scale experiments, typically in the form of wave-tank experiments provide a much more realistic source of data that better captures the complex dynamics of natural tsunami, whilst allowing control of the event and much easier and accurate measurement of the tsunami properties. However comparison of numerical predictions with field data provides the most stringent test of model veracity. The use of field data increases the generality and significance of conclusions made regarding model utility. However the use of field data also significantly increases the uncertainty of the validation experiment that may constrain the ability to make unequivocal statements~\cite{bates01}. 42 43 Currently the extent of tsunami related field data is limited. The cost of tsunami monitoring programs and bathymetry and topography surveys prohibits the collection of data in many of the regions in which tsunamis pose greatest threat. The resulting lack of data has limited the number of field data sets available to validate tsunami models, particularly those modelling tsunami inundation. Synolakis et. al~\cite{synolakis07} have developed a set of standards, criteria and procedures for evaluating numerical models of tsunami. They propose three analytical solutions to help identify the validity of a model and five scale comparisons (wave-tank benchmarks) and two field events to assess model veracity. The two field data benchmarks are very useful but only capture a small subset of possible tsunami behaviours. The type and size of a tsunami source, propagation extent, and local bathymetry and topography all affect the energy, waveform and subsequent inundation of a tsunami. Consequently additional field data benchmarks that further capture the variability and sensitivity of the real world system would be useful to allow model developers verify their models and subsequently use their models with greater confidence. 44 45 In this paper we develop a field data benchmark to be used in conjunction with the other tests proposed by Synolakis et al.~\cite{synolakis07} to validate and verify tsunami inundation. The benchmark is constructed from data collected around Patong Bay, Thailand immediately following the 2004 Indian Ocean tsunami. This area was chosen because the authors were able to obtain high resolution bathymetry and topography data in this area and an inundation map generated from a survey performed in the aftermath of the tsunami. A description of this data is give in Section~\ref{sec:data}. 46 47 An associated aim of this paper is to illustrate the use of this new benchmark to validate an operational tsunami model called \textsc{anuga} (see Secion~\ref{sec:veri_procedure}). The specific intention is to test the ability of \textsc{anuga} to reproduce the inundation survey of maximum runup. \textsc{Anuga} is a hydrodynamic modelling tool used to simulate the tsunami propagation and run rain-induced floods. 48 49 %================Section=========================== 50 51 \section{Event Description} 52 The devastation caused by the 2004 Samatra-Andaman tsunami has heightened community, scientific and governmental interest in tsunami and in doing so has provided a unique opportunity for further validation of tsunami models. Data sets from seismometers, tide gauges, GPS stations, a few satellite overpasses, subsequent coastal field surveys of run-up and flooding and measurements from ship-based expeditions, have now been made available~\cite{vigny05,amnon05,kawata05,liu05}. A number of studies have utilised this data to calibrate models of the tsunami source\cite{asavanant08,arcas06,grilli07,ioualalen07}. We propose to use this event as an additional field-data benchmark for verification of tsunami models. This event captures certain tsunami behaviours that are not present in the benchmarks proposed by Synolakis et. al~\cite{synolakis07}. FIXME: What kind of behaviours??? 51 53 52 54 Synolakis detail two field data benchmarks. The first test compares model results against observed data from the Hokkaido-Nansei-Oki tsunami that occurred around Okushiri Island, Japan on the 12th of July 1993. This tsunami provides an example of extreme runup generated from reflections and constructive interference resulting from local topography and bathymetry. The benchmark consists of two tide gauge records and numerous spatially distributed point sites at which maximum runup elevations were observed. The second benchmark is based upon the Rat Islands Tsunami that occurred off the coast of Alaska on the 17th of November 2003. Rat island tsunami provides a good test for real-time forecasting models since tsunami was recorded at three tsunameters. The test requires matching the propagation model data with the DART recording to constrain the tsunami source model and using a propagation model to to reproduce the tide gauge record at Hilo. 53 55 54 %The tsunamis used by the two standard benchmarks and the 2004 tsunami are quite different. They all arise from coseismic displacement resulting from an earthquake, however they all occur in very different geographical regions. The Hokkaido-Nansei-Oki tsunami was generated by an earthquake with a magnitude of 7.8 and only travelled a small distance before inundating Okishiri Island. The event provides an example of extreme runup generated from reflections and constructive interference resulting from local topography and bathymetry. In comparison the Rat islands tsunami was generated by an earthquake of the same magnitude but had to travel a much greater distance. The event provides a number of tide gauge recordings that capture the change in wave form as the tsunami evolved.55 56 56 The 2004 Indian Ocean tsunami was a much larger event than the previous two described (See Section \ref{sec:source}). Consequently the energy of the resulting wave was much larger than the waves generated from the more localised and smaller magnitude aforementioned events. WAS THE WAVELENGTH< VELOCITY (and thus average ocean depth) DIFFERENT FROM THESE TWO EVENTS??? If so state something like. This larger wavelength and energy and simply the different geology of the area produced different a wave signal and different pattern of inundation. Here we focus on the large inundation experienced at Patong Bay on the west coast of Thailand. 57 57 58 58 \section{Data}\label{sec:data} 59 (FIXME (OLE): Remove? Hydrodynamic simulations require very little data in comparison to models of many other environmental systems). Tsunami models typically only require baythymetry and topography data to approximate the local geography, parameterisation of the tsunami source from which appropriate initial conditions can be generated, and a locally distributed quantity such as Manning's friction coefficient to approximate friction. Here we discuss the bathymetric and topographical data sets and source condition that are necessary to implement the proposed benchmark. Friction is discussed in Section~\ref{sec:inundation} 60 61 An unusually large amount of data for the 2004 tsunami, necessary for tsunami verification, is available at Patong Bay and surrounding regions. A number of raw data sets were obtained, analysed and checked for quality and subsequently gridded for easier visualisation and input into the tsunami models. 59 Tsunami models typically require baythymetry and topography data to approximate the local geography, parameterisation of the tsunami source from which appropriate initial conditions can be generated, and certain paramter values such Manning's friction coefficient. Here we discuss the ncessary data needed to implement the proposed benchmark. 62 60 63 61 \subsection{Bathymetric and topographic data} 64 65 NOTE: Richard, could you please look into these issues and also those in your appendix? 66 67 FIXME(OLE): Need Intro to this section aka: we obtained data sets at different resolutions from various sources and merged them to build a model appropriate for inundation modelling. The resolution required was generally relatively coarse in the deeper water and progressively finer towards the bay itself with the finest data in the intertidal zone and around the built environment. 68 62 An unusually large amount of data for the 2004 tsunami, necessary for tsunami verification, is available at Patong Bay and surrounding regions. A number of raw data sets were obtained, analysed and checked for quality and subsequently gridded for easier visualisation and input into the tsunami models. The resulting grid data is relatively coarse in the deeper water and becomes progressively finer as the distance to Patong Bay decreases. 69 63 70 64 The two minute arc grid data set, DBDB2, was obtained from US Naval Research Labs and used to approximate the bathymetry in the Bay of Bengal. This grid was further interpolated to a 27 second arc grid. In the Andaman Sea the DBDB2 data was replaced with a 3 second grid obtained from NOAA (REF?). Finally, a 1 second grid was used to approximate the bathymetry in Patong Bay and the immediately adjacent regions (FROM WHERE?). This elevation data was created from the digitised Thai Navy bathymetry chart, no 358. A visualisation of the elevation data set used in Patong bay is shown in Figure~\ref{fig:patong_bathymetry}. The continuous topography is an interpolation of known elevation measured at the coloured dots. 71 72 The sub-sampling of larger grids was performed by using {\bf resample} a GMT program (\cite{XXX}). The gridding of data was performed using {\bf Intrepid} a commercial geophysical processing package developed by Intrepid Geophysics. The gridding scheme employed the nearest neighbour algorithm followed by and application of minimum curvature akima spline smoothing.73 74 65 75 66 \begin{figure}[ht] 76 67 \begin{center} 77 68 \includegraphics[width=8.0cm,keepaspectratio=true]{patong_bay_data.jpg} 78 \caption{ Is there a new picture with river included???}69 \caption{Visualisation of the elevation data set used in Patong Bay. FIXME: Can we generate a new picture with river included Preferably without the arrows and logo???} 79 70 \label{fig:patong_bathymetry} 80 71 \end{center} 81 72 \end{figure} 82 73 83 Details of the lineage of this dataset is outlined in Appendix~\ref{XXXXX} and the final dataset 84 is available at XXXX. 85 74 The sub-sampling of larger grids was performed by using {\bf resample} a GMT program (\cite{XXX}). The gridding of data was performed using {\bf Intrepid} a commercial geophysical processing package developed by Intrepid Geophysics. The gridding scheme employed the nearest neighbour algorithm followed by and application of minimum curvature akima spline smoothing. Details of the lineage of this dataset is outlined in the Appendix and the final dataset is available at XXXX. 75 76 77 FIXME(Richard): Could you please look into these issues and also those in your appendix? 86 78 87 79 \subsection{Tsunami source}\label{sec:source} 88 80 89 NOTE: Richard, could you please look into these issues 90 91 92 The 2004 Indian Ocean tsunami was generated by severe coseismic displacement of the sea floor as a result of one of the largest earthquakes on record. The M$_w$=9.3 mega-thrust earthquake occurred on the 26 December 2004 at 0h58'53'' UTC approximately 70 km offshore North Sumatra. The disturbance propagated 1200-1300 km along the Sumatra-Andaman trench time at a rate of 2.5-3 km.s$^{-1}$ and lasted approximately 8-10 minutes (Amnon {\it et al.} 2005)\nocite{amnon05}. 93 94 Many models of this earthquake are available FIXME: CITATIONS NEEDED \cite{YYY}. Some are determined from various geological surveys of the site, others solve an inverse problem which calibrates the source based upon the tsunami wave signal and or runup. The source parameters used to simulate the 2004 Indian Ocean Tsunami were taken from Chlieh (2007) \cite{XXX}. 95 This model was created by inversion of the seismic data and fits both coseismic, tsunami and GPS data in the Andaman Sea well. DOES ANYONE HAVE A COPY THEY COULD SEND ME PLEASE? The resulting sea floor displacement ranges from about - 5.0 to 5.0 metres and is shown in Figure~\ref{fig:chlieh_slip_model}. 81 The 2004 Indian Ocean tsunami was generated by severe coseismic displacement of the sea floor as a result of one of the largest earthquakes on record. The M$_w$=9.3 mega-thrust earthquake occurred on the 26 December 2004 at 0h58'53'' UTC approximately 70 km offshore North Sumatra. The disturbance propagated 1200-1300 km along the Sumatra-Andaman trench time at a rate of 2.5-3 km.s$^{-1}$ and lasted approximately 8-10 minutes~\cite{amnon05}. 82 83 Many models of this earthquake are available~\cite{chlieh07,XXX}. Some are determined from various geological surveys of the site, others solve an inverse problem which calibrates the source based upon the tsunami wave signal and or runup. The source parameters used to simulate the 2004 Indian Ocean Tsunami were taken from Chlieh~\cite{chlieh07}. This model was created by inversion of the seismic data from GPS measurements and fits both coseismic, tsunami and GPS data in the Andaman Sea well. The resulting sea floor displacement ranges from about - 5.0 to 5.0 metres and is shown in Figure~\ref{fig:chlieh_slip_model}. 96 84 97 85 \begin{figure}[ht] 98 86 \begin{center} 99 \includegraphics[width= 8.0cm,keepaspectratio=true]{chlieh_slip_model.png}100 \caption{Location and magnitude of the sea floor displacement associated with the 2004 Indian Ocean tsunami. Source parameters from Chlieh {\it et al.} (2007) \cite{XXX}}87 \includegraphics[width=5.0cm,keepaspectratio=true]{chlieh_slip_model.png} 88 \caption{Location and magnitude of the sea floor displacement associated with the 2004 Indian Ocean tsunami. Source parameters from Chlieh et al.~\cite{chlieh07}} 101 89 \label{fig:chlieh_slip_model} 102 90 \end{center} 103 91 \end{figure} 104 92 105 \subsection{Inundation survey data} 106 107 ... 108 109 FIXME: This needs to be rephrased. This is about survey data not about bathymetric and source parameters. And it appears that this paragraph really belongs under the next section. 110 111 The bathymetry data and source parameterisation can be inserted into the tsunami model and run. From the simulation runup and ocean surface elevation can be obtained. We propose that a `correct' tsunami model should reproduce the inundation map shown in Figure~\ref{fig:patongescapemap}. Furthermore the model should simulate a leading depression followed by 3??? crests. Is there any eye witness accounts of how many waves arrived a patong??? FIXME: Who will chase this? Richard has the video footage recorded, can you do it? 93 \subsection{Validation data} 94 Eyewitness accounts detailed in~\cite{papadopoulos06} report that most people at Patong Beach observed an initial retreat of the shoreline of more than 100m followed a few minutes later by a strong wave (crest). Another less powerful wave arrived another five or ten minutes later. Eyewitness statments place the arrival time of the strong wave between 2 hours and 55 inutes to 3 hours and 5 minutes after the source rupture (09:55am to 10:05am local time). After the event (HOw long?) a survey mapped the maximum observed inundation at Patong beach. The inundation map is shown in Figure~\ref{fig:patongescapemap} and was obatined from the Thai Department of Mineral Resources \protect \cite{XXX}. 112 95 113 96 \begin{figure}[ht] … … 119 102 \end{figure} 120 103 121 104 FIXME(Richard): More information deailting construction of this map is needed here. Is more accurate information on arrival times of crests and depression available 105 106 %================Section=========================== 122 107 \section{Verification Procedure}\label{sec:veri_procedure} 123 124 %=================Section===================== 108 Intro\\\\ 109 110 The following observations need to be matched by any numerical tsuanmi model: 111 \begin{itemize} 112 \item Simulate a leading depression followed by two distinct crests of decreasing magnitude. 113 \item The arrival time of the first crest should arrive at Patong beach bewtween 2 hours and 55 inutes to 3 hours and 5 minutes after the intial rupture of the source. The subsequent crest arrive five to ten minutes later. 114 \item Simulated inundation in Patong bay should reproduce well the inundation map in Figure~\ref{fig:patongescapemap}. 115 \end{itemize} 116 125 117 126 118 \subsection{ANUGA} 127 ANUGA is an Open Source hydrodynamic inundation tool that solves the depth integrated nonlinear shallow water wave equations. The scheme used by ANUGA, first presented by Zoppou and Roberts (1999)\nocite{zoppou99}, is a high-resolution Godunov-type method that uses the rotational invariance property of the shallow water equations to transform the two-dimensional problem into local one-dimensional problems. These local Riemann problems are then solved using the semi-discrete central-upwind scheme of Kurganov {\it et al.} (2001) \nocite{kurganov01} for solving one-dimensional conservation equations. The numerical scheme is presented in detail in (Zoppou and Roberts 1999, Zoppou and Roberts 2000, and Roberts and Zoppou 2000, Nielsen {\it et al.} 2005) \nocite{zoppou99,zoppou00,roberts00,nielsen05}. An important capability of the software is that it can model the process of wetting and drying as water enters and leaves an area. This means that it is suitable for simulating water flow onto a beach or dry land and around structures such as buildings. It is also capable of adequately resolving hydraulic jumps due to the ability of the finite-volume method to handle discontinuities. ANUGA has been validated against a number of analytical solutions and the wave tank simulation of the 1993 Okushiri Island tsunami (Roberts {\it et al.} 2006 and Nielsen {\it et al.} 2005) \nocite{roberts06,nielsen05}.119 \textsc{Anuga} is an Open Source hydrodynamic inundation tool that solves the depth integrated nonlinear shallow water wave equations. The scheme used by \textsc{anuga}, first presented by Zoppou and Roberts~\cite{zoppou99}, is a high-resolution Godunov-type method that uses the rotational invariance property of the shallow water equations to transform the two-dimensional problem into local one-dimensional problems. These local Riemann problems are then solved using the semi-discrete central-upwind scheme of Kurganov et al.~\cite{kurganov01} for solving one-dimensional conservation equations. The numerical scheme is presented in detail in Zoppou and Roberts~\cite{zoppou99}, Zoppou and Roberts~\cite{zoppou00}, and Roberts and Zoppou~\cite{roberts00}, Nielsen et al.~\cite{nielsen05}. An important capability of the software is that it can model the process of wetting and drying as water enters and leaves an area. This means that it is suitable for simulating water flow onto a beach or dry land and around structures such as buildings. It is also capable of adequately resolving hydraulic jumps due to the ability of the finite-volume method to handle discontinuities. \textsc{Anuga} has been validated against a number of analytical solutions and the wave tank simulation of the 1993 Okushiri Island tsunami~\cite{roberts06,nielsen05}. 128 120 129 121 \subsection{URSGA} 130 URSGA is a hydrodynamic code that models the propagation of the tsunami in deep water using the finite difference method to solve the depth integrated nonlinear shallow water equations in spherical co-ordinates with friction and Coriolis terms. The code is based on Satake (1995) with significant modifications made by the URS corporation (Thio et al. 2007) and Geoscience Australia (Burbidge et al. 2007). The tsunami is propagated via a staggered grid system starting with coarser grids and ending with the finest one. URSGAis not publicly available. FIXME: Check with David.122 \textsc{ursga} is a hydrodynamic code that models the propagation of the tsunami in deep water using the finite difference method to solve the depth integrated nonlinear shallow water equations in spherical co-ordinates with friction and Coriolis terms. The code is based on Satake~\cite{satake95} with significant modifications made by the URS corporation~\cite{thio07} and Geoscience Australia~\cite{burbidge07}. The tsunami is propagated via a staggered grid system. Coarse grids are used in the open ocean and the finest resolution grid is employed in the region of most interest. \textsc{Ursga} is not publicly available. FIXME: Check with David. 131 123 132 124 133 125 \subsection{Tsunami Source and Propagation} 134 The utility of the URSGA model decreases with water depth unless an intricate sequence of nested grids is employed. In comparison ANUGA is designed to produce robust and accurate predictions of on-shore inundation in mind, but is less suitable for earthquake source modelling and large study areas. Consequently, the Geoscience Australia tsunami modelling methodology is based on a hybrid approach using models like URSGA for tsunami generation and propagation up to a 100m depth contour. This information then forms a boundary condition for ANUGA and is propagated on shore to model the inundation. Specifically we use the URSGA model to simulate the propagation of the 2004 Indian Ocean tsunami in the deep ocean, based on a discrete representation of the initial deformation of the sea floor, described in Section~\ref{sec:source}. The resulting tsunami was propagated over the entire Bay of Bengal and the wave signal measured along the 100m depth contour offshore Phuket, Thailand. The wave signal is then used as a time varying boundary condition for the ANUGAinundation simulation.135 136 ???The URS code is also capable of calculating inundation. CAN WE PRODUCE AN INUNDATION MAP OVER THE SAME AREA TO COMPARE WITH ANUGA???126 The utility of the \textsc{ursga} model decreases with water depth unless an intricate sequence of nested grids is employed. In comparison \textsc{anuga} is designed to produce robust and accurate predictions of on-shore inundation in mind, but is less suitable for earthquake source modelling and large study areas. Consequently, the Geoscience Australia tsunami modelling methodology is based on a hybrid approach using models like \textsc{ursga} for tsunami generation and propagation up to a 100m depth contour. This information then forms a boundary condition for \textsc{anuga} and is propagated on shore to model the inundation. Specifically we use the \textsc{ursga} model to simulate the propagation of the 2004 Indian Ocean tsunami in the deep ocean, based on a discrete representation of the initial deformation of the sea floor, described in Section~\ref{sec:source}. The resulting tsunami was propagated over the entire Bay of Bengal and the wave signal measured along the 100m depth contour offshore Phuket, Thailand. The wave signal is then used as a time varying boundary condition for the \textsc{anuga} inundation simulation. 127 128 ???The \textsc{ursga} code is also capable of calculating inundation. CAN WE PRODUCE AN INUNDATION MAP OVER THE SAME AREA TO COMPARE WITH \textsc{anuga}??? 137 129 138 130 \subsection{Tsunami Inundation}\label{sec:inundation} 139 In this case the open ocean boundary of the ANUGA study areawas chosen to roughly follow the 100m depth contour along the west coast of Phuket Island. The computational domain is shown in Figure \ref{fig:computational_domain}131 In this case the interface betwen the \textsc{ursga} and \textsc{anuga} models was chosen to roughly follow the 100m depth contour along the west coast of Phuket Island. The computational domain is shown in Figure \ref{fig:computational_domain} 140 132 \begin{figure}[ht] 141 133 \begin{center} 142 \includegraphics[width=8.0cm,keepaspectratio=true]{new_domain.png} 143 \caption{Computational domain of the ANUGA simulation. CAN WE CREATE A PICTURE LIKE THIS FOR OUR NEW SCENARIO??? 144 FIXME: Is this still the case?} 134 \includegraphics[width=5.0cm,keepaspectratio=true]{new_domain.png} 135 \caption{Computational domain of the \textsc{anuga} simulation. FIXME: Insert picture of new domain here.} 145 136 \label{fig:computational_domain} 146 137 \end{center} … … 151 142 The boundary condition at each side of the domain towards the south and the north where no data was available was chosen as a transmissive boundary condition effectively replicating the time dependent wave height present just inside the computational domain. Momentum was set to zero. Other choices include applying the mean tide value as a Dirichlet type boundary condition but experiments as well as the result of the verification reported here showed that this approach tends to under estimate the tsunami impact due to the tempering of the wave near the side boundaries. FIXME(OLE): Should we include Nick's test example? 152 143 153 %================Section====================== 144 %================Section=========================== 154 145 \section{Results} 155 146 Maximum onshore inundation elevation was simulated throughout the entire Patong Bay region. Figure~\ref{fig:inundationcomparison1cm} shows very good agreement between the measured and simulated inundation. Discrepencies between the survey data and the modelled inundated area are apparant and would be due to a number of issues: These include uncertainties in the elevation data, simplifications in the models involved, effects of erosion and deposition by the tsunami event, unknown distribution of surface roughness, as well as measurement errors and missing data in the field survey data itself. … … 160 151 FIXME: Take some of this commentary after final runs have been completed. 161 152 FIXME: Also need a commentary on the dynamics of what is being observed and whether it aligns with eye witness observations. 162 %The ANUGA simulation determines a region to be inundated if at some point in time it was covered by at least 1cm of water. This precision in field measurements is impossible to obtain. The inundation boundary is determined by observing water marks and other signs left by the receeding waters. The precision of the observed inundation map is, most likely, at least an order of magnitude worse than the ANUGA simulation. The simulated inundation based upon a 10cm threshold is shown in Figure~\ref{fig:inundationcomparison10cm}. 163 164 Both the URS model and the ANUGA inundation model shows that the event comprises a train of waves some with preciding drawdown effects (ADD details of waveform with a graph from URL and a gauge from ANUGA and discuss). In \cite{papadopoulos06} eyewitness accounts report 165 \emph{In Patong beach, most people observed at least two 166 waves. It is likely that the leading wave described in both 167 Sri Lanka and Maldives was not observed in Patong beach. 168 What people said is that the first sea motion was a retreat 169 of more than 100 m. A few minutes later the strong wave 170 arrived. Then, after another 5 or 10 min. one more wave attacked 171 but less violently than the first one. Nearly all the 172 interviewed persons reported that the tsunami inundation 173 in the Patong beach varied from 150 m to at least 750 m 174 (Fig. 16). One eyewitness reported inundation of only 20 175 m. As for the arrival time of the strong wave the eyewitnesses 176 do not agree. However, most reports concentrated 177 around 02:55 to 03:05 (09:55 to 10:05 local) which seems 178 to be a reliable description.} 179 180 FIXME(Ole): Need discussion of model results in this context. 181 182 153 %The \textsc{anuga} simulation determines a region to be inundated if at some point in time it was covered by at least 1cm of water. This precision in field measurements is impossible to obtain. The inundation boundary is determined by observing water marks and other signs left by the receeding waters. The precision of the observed inundation map is, most likely, at least an order of magnitude worse than the \textsc{anuga} simulation. The simulated inundation based upon a 10cm threshold is shown in Figure~\ref{fig:inundationcomparison10cm}. 154 155 Both the URS model and the \textsc{anuga} inundation model shows that the event comprises a train of waves some with preciding drawdown effects (ADD details of waveform with a graph from URL and a gauge from \textsc{anuga} and discuss). 183 156 184 157 \begin{figure}[ht] … … 193 166 194 167 195 %================Section===================== 168 %================Section=========================== 196 169 197 170 \section{Conclusion} 198 171 This paper proposes an additional field data benchmark for the verification of tsunami inundation models. Currently, there is a scarcity of appropriate validation datasets due to a lack of well documented historical tsunami impacts. This new benchmark involves the comparison of model predictions of onshore inundation in Patong Bay, Phuket Thailand caused by the 2004 Indian Ocean tsunami. Specifically a field survey mapping of observed inundation is used as a spatially distributed test of model performance. Although two other field data benchmarks exist (FIXME: WHICH?), this proposed benchmark provides a novel investigation of the dynamics of extreme tsunami events not before tested. The benchmark could be further improved with the inclusion of local tide gauge data, against which wave signal could be compared, however, to the authors knowledge no such data exist for this event. 199 172 200 This paper also illustrates the effectiveness of the proposed new benchmark. The benchmark is used to test the veracity of the hydrodynamic ANUGA designed spcefically to model on-shore inundation. Very good agreement is obtained between the observed and simulated runup. The URSGAtsunami package was also tested. Much worse results were obtained??173 This paper also illustrates the effectiveness of the proposed new benchmark. The benchmark is used to test the veracity of the hydrodynamic \textsc{anuga} designed spcefically to model on-shore inundation. Very good agreement is obtained between the observed and simulated runup. The \textsc{ursga} tsunami package was also tested. Much worse results were obtained?? 201 174 202 175 203 176 %================Acknowledgement=================== 204 \section {Acknowledgements}177 \section*{Acknowledgements} 205 178 This project was undertaken at Geoscience Australia and the Department of Mathematics, The Australian National University. The authors would like to thank Niran Chaimanee from the CCOP, Thailand for providing the post 2004 tsunami survey data and the elevation data for Patong beach. 206 179 207 208 209 FIXME: Cite more of these and use the proper citation system of LaTeX or even BiBTeX. 210 211 %====================Bibliography============== 212 %\bibliographystyle{thebibliography} 213 %\bibliography{tsunami07} 214 215 % GET Bib item from end of this document for Papadopoulus06 180 %====================Bibliography================== 181 \bibliographystyle{plain} 182 \bibliography{tsunami07} 183 184 %===============Appendicies======================== 185 186 \section*{Appendix A. Figures and Tables} 187 \label{sec:appendix} 188 \subsection*{Datasets and gridding} 189 190 This section outlines the origins and processes by which the elevation data was created. In general high resolution data sets were embedded into coarser data sets to match the modelled areas of interest. 191 192 193 FIXME: Is there a standard template for data lineage. 194 195 \begin{verbatim} 196 E.g. 197 Data Source: 198 2 min: DBDB 2 199 9 sec: NOAA 200 3 sec: aontehusoe 201 202 203 Process: 204 ... 205 ... 206 ... 207 \end{verbatim} 208 209 FIXME: Could we have a map with the nested data sets? 210 211 212 213 214 215 Gridded data sets used: 216 217 DBDB2 2 minute of arc grid from the US Naval Research Labs. 218 This grid was also interpolated to 27 sec of arc and used in a nested grid scheme. 219 220 Indian Ocean 27 sec of arc grid created by: 221 Interpolating the DBDB2 2 minute of arc grid. 222 In the region where the 9 sec grid sits the data was cut out and replaced by the 9 sec data. 223 Any points that deviated from the general trend near the boundary were deleted. 224 The data was then re-gridded. 225 226 Andaman Sea 9 sec of arc grid created by: 227 Sub-sampling the 3 sec of arc grid from NOAA. 228 In the region where the 3 sec grid sits the data was cut out and replaced by the 3 sec data. 229 Any points that deviated from the general trend near the boundary were deleted. 230 The data was then re-gridded. 231 232 Thailand off-shore 3 sec of arc grid created by: 233 cropping a much larger 3 sec of arc grid covering the whole of the Andaman Sea which itself was based on Thai charts 45 and 362. 234 This grid was obtained from NOAA. 235 In the region where the 1 sec grid sits the data was cut out and replaced by the 1 sec data. 236 Any points that deviated from the general trend near the boundary were deleted. 237 The data was then re-gridded. 238 239 Patong Bay 1 second of arc grid created from: 240 elevation data contained in a GIS of Patong Bay supplied by Niran Chaimanee, Geo-environment Sector Manager, CCOP T/S, Bangkok. 241 Digitised Thai Navy bathymetry chart no 358. 242 243 The sub-sampling of larger grids was performed by using {\bf resample} a GMT program. 244 The gridding of data was performed using {\bf Intrepid} a commercial geophysical processing package developed by Intrepid Geophysics. 245 The gridding scheme was nearest neighbour followed by minimum curvature akima spline smoothing. 246 247 248 249 \subsection*{Earthquake Source Model} 250 FIXME: Is this appendix needed? 251 252 The earthquake source model of Chlieh was adopted to generate the tsunami simulation. This model was created by carefull inversion of the seismic 253 data and fits both coseismic, tsunami and GPS data in the Andaman Sea well. 254 255 \subsection*{Tsunami Propagation} 256 FIXME: Is this appendix needed? 257 258 To to generate and propagate the tsunami the URS code was used. This program solves the shallow water equations using the finite difference method. 259 It can also be used in a nexted grid scheme and does on-shore inundation. 260 261 %%%%%%%%%%%%%%%%%%%%%%% 262 263 \end{document} 264 265 266 Main source of uncertainty arises from inaccuracies in initial condition (source), inaccurate bathymetry data, to a lesser extent friction 267 268 single experiment can refute model but cannot validate it. Need as many tests as possible to be confident in rpediction. Question arises. How mnay should we do. With finite experiments more weight should be given to a particular experiment if the range of the inout function and the material properties are both broad so that the universal character of the model is tested. 269 270 Expressions: 271 sufficient verification/falsification of model 272 Confidently utilise a model 273 274 Predictive valdiation of only one aspect of model evaluation. Need to assess model explanation. 275 276 Conservation of mass 277 convergence 278 279 spatial and temporal discretisation errors, round off errors due to limited numerical precision 280 281 analytical benchmarking: 282 ensuring equations are solved accurately 283 single wave on a beach 284 Solitary wave on composite beach 285 subaerial landslide on simple beach 286 287 Analytical solutions only represent idealised and simplfied events that do not fully capture the complexity of 'real' flows. Provide temporally and spatially distributed data that field data can rearely match. 288 289 scale comparisions (laboratory benchmarking): 290 Scale differences are not belived to be important. scale experiments generally do not have same bootom firction characteristics as real scenario but has not proven to be a problem. The long wavelngth of tsunami tends to mean that the friction is less important in comparison to the motion of the wave 291 Single wave on a simple beacj 292 Solitary wave on composite beach 293 Conical island 294 Monai Valley 295 Landslide 296 297 includes comparisons with validation data sets generated by other models of higher dimensionality and resolution. 298 299 Often flow geometries are simplified 300 301 302 Field benchmarking: 303 Most important verification process 304 Hydrodynamic inversion to predict the source is an ill posed problem 305 12 July 1993 Hokkaido-Nansei-Oki tsunami around Okushiri Island Japan exreme runup height of 31.7m was found at the tip of a narrow gulley with the small cove at Monai 306 17 November 2003 Rat Islands Tsunami 307 308 Construction of more than one model can reveal biases in a single model. Two types of comparisons 1 between those that are comceptually simailar and those that re different. In former case interested in how choice of numerical solver and discretisation effects results and the later can help determine the level of physical processs representation necessary to represent an observed data set. 309 310 Movinf to field data increases the gnereality and siginificance of svientifice evidence obatined. However we also significantly incerase the uncertainty of the validation experioment that may constrain the ability to make unequivacol statments. E.g. in bathymetry source condition friction. 311 312 Calibratino of the model is often used to compensate for uncertainty in the model inputs. Calibartion results in a further loss of experimental control as a unique solution may not exist. 313 314 verfication need to assess point data, spatially distributed data and bulk (lumped) data. 315 316 Synolakis et. al~\cite{synolakis07} detail two field events that have been previoulsy used to validate tsunami models, the Hokkaido-Nansei-Oki tsunami that occured around Okushiri Island, Japan on 2nd of July 1993 and the Rat Islands Tsunami that inundated the occured off the coast of Alaska on the 17th of November 2003. 317 318 319 inundation map only useful if mesh and topography resolution fine enough hard to measure what the model predicts how deep does inundation need to be for it to be visible during a field study 320 321 Notes: 322 Okushiri provides an example of extreme runup genereated from reflections and constructive interference resulting from local topography and bathymetry. Numerous point sites at which runup elevations were observed are available. The highest runup of 31.7 m in a valley north of Monai needs to be approximated with the numerical model. In addition, two tide gage records at Iwanai and Esashi need to be estimated. 323 324 325 326 Rat Island tsuanmi provides a good test for real-time forecasting models since tsnumai was recorded at three tsunameters. The test requires matching the propagation model data with the recordings to constrain the tsunami source model. The inundation model is to reproduce the tide gauge record at Hilo. 327 328 Patong Bay benchmark provides spatially distributed field data for comparison. 329 330 single experiment can refute model but cannot validate it. Need as many tests as possible to be confident in prediction. Question arises. How mnay should we do. 331 332 DO I SAY WE HAVE MUX @ FILES DESCRIBING SHAPE OF WAVE YES. MAKES CONSISTENT 333 334 Notes: * Model source developed independently of inundation data. 335 * Patong region was chosen because high resolution inundation map and bathymetry and topography data was available there 336 337 Geoscience Australia, in an open collaboration with the Mathematical Sciences Institute, The Australian National University, is developing a software application, \textsc{anuga}, to model the hydrodynamics of tsunamis, floods and storm surges. The open source software implements a finite volume central-upwind Godunov method to solve the non-linear depth-averaged shallow water wave equations. This paper investigates the veracity of \textsc{anuga} when used to model tsunami inundation. A particular aim was to make use of the comparatively large amount of observed data corresponding to the Indian ocean tsunmai event of December 2004, to provide a conditional assessment of the computational model's performance. Specifically a comparison is made between an inundation map, constructed from observed data, against modelled maximum inundation. This comparison shows that there is very good agreement between the simulated and observed values. The sensitivity of model results to the resolution of bathymetry data used in the model was also investigated. It was found that the performance of the model could be drastically improved by using finer bathymetric data which better captures local topographic features. The effects of two different source models was also explored. 338 339 different even types submarine mass failure generate larger events because of proximity more directional wave generation 340 341 even if data is available it is hard to access 216 342 217 343 \begin{thebibliography}{7} … … 282 408 \end{thebibliography} 283 409 284 285 %===============Appendicis 286 287 \section*{Appendix A. Figures and Tables} 288 289 \subsection{Datasets and gridding} 290 291 This section outlines the origins and processes by which the elevation data was created. In general high resolution data sets were embedded into coarser data sets to match the modelled areas of interest. 292 293 294 FIXME: Is there a standard template for data lineage. 295 296 \begin{verbatim} 297 E.g. 298 Data Source: 299 2 min: DBDB 2 300 9 sec: NOAA 301 3 sec: aontehusoe 302 303 304 Process: 305 ... 306 ... 307 ... 308 \end{verbatim} 309 310 FIXME: Could we have a map with the nested data sets? 311 312 313 314 315 316 Gridded data sets used: 317 318 DBDB2 2 minute of arc grid from the US Naval Research Labs. 319 This grid was also interpolated to 27 sec of arc and used in a nested grid scheme. 320 321 Indian Ocean 27 sec of arc grid created by: 322 Interpolating the DBDB2 2 minute of arc grid. 323 In the region where the 9 sec grid sits the data was cut out and replaced by the 9 sec data. 324 Any points that deviated from the general trend near the boundary were deleted. 325 The data was then re-gridded. 326 327 Andaman Sea 9 sec of arc grid created by: 328 Sub-sampling the 3 sec of arc grid from NOAA. 329 In the region where the 3 sec grid sits the data was cut out and replaced by the 3 sec data. 330 Any points that deviated from the general trend near the boundary were deleted. 331 The data was then re-gridded. 332 333 Thailand off-shore 3 sec of arc grid created by: 334 cropping a much larger 3 sec of arc grid covering the whole of the Andaman Sea which itself was based on Thai charts 45 and 362. 335 This grid was obtained from NOAA. 336 In the region where the 1 sec grid sits the data was cut out and replaced by the 1 sec data. 337 Any points that deviated from the general trend near the boundary were deleted. 338 The data was then re-gridded. 339 340 Patong Bay 1 second of arc grid created from: 341 elevation data contained in a GIS of Patong Bay supplied by Niran Chaimanee, Geo-environment Sector Manager, CCOP T/S, Bangkok. 342 Digitised Thai Navy bathymetry chart no 358. 343 344 The sub-sampling of larger grids was performed by using {\bf resample} a GMT program. 345 The gridding of data was performed using {\bf Intrepid} a commercial geophysical processing package developed by Intrepid Geophysics. 346 The gridding scheme was nearest neighbour followed by minimum curvature akima spline smoothing. 347 348 349 350 \subsection{Earthquake Source Model} 351 FIXME: Is this appendix needed? 352 353 The earthquake source model of Chlieh was adopted to generate the tsunami simulation. This model was created by carefull inversion of the seismic 354 data and fits both coseismic, tsunami and GPS data in the Andaman Sea well. 355 356 \subsection{Tsunami Propagation} 357 FIXME: Is this appendix needed? 358 359 To to generate and propagate the tsunami the URS code was used. This program solves the shallow water equations using the finite difference method. 360 It can also be used in a nexted grid scheme and does on-shore inundation. 361 362 %%%%%%%%%%%%%%%%%%%%%%% 363 364 \end{document} 365 366 367 Main source of uncertainty arises from inaccuracies in initial condition (source), inaccurate bathymetry data, to a lesser extent friction 368 369 single experiment can refute model but cannot validate it. Need as many tests as possible to be confident in rpediction. Question arises. How mnay should we do. With finite experiments more weight should be given to a particular experiment if the range of the inout function and the material properties are both broad so that the universal character of the model is tested. 370 371 Expressions: 372 sufficient verification/falsification of model 373 Confidently utilise a model 374 375 Predictive valdiation of only one aspect of model evaluation. Need to assess model explanation. 376 377 Conservation of mass 378 convergence 379 380 spatial and temporal discretisation errors, round off errors due to limited numerical precision 381 382 analytical benchmarking: 383 ensuring equations are solved accurately 384 single wave on a beach 385 Solitary wave on composite beach 386 subaerial landslide on simple beach 387 388 Analytical solutions only represent idealised and simplfied events that do not fully capture the complexity of 'real' flows. Provide temporally and spatially distributed data that field data can rearely match. 389 390 scale comparisions (laboratory benchmarking): 391 Scale differences are not belived to be important. scale experiments generally do not have same bootom firction characteristics as real scenario but has not proven to be a problem. The long wavelngth of tsunami tends to mean that the friction is less important in comparison to the motion of the wave 392 Single wave on a simple beacj 393 Solitary wave on composite beach 394 Conical island 395 Monai Valley 396 Landslide 397 398 includes comparisons with validation data sets generated by other models of higher dimensionality and resolution. 399 400 Often flow geometries are simplified 401 402 403 Field benchmarking: 404 Most important verification process 405 Hydrodynamic inversion to predict the source is an ill posed problem 406 12 July 1993 Hokkaido-Nansei-Oki tsunami around Okushiri Island Japan exreme runup height of 31.7m was found at the tip of a narrow gulley with the small cove at Monai 407 17 November 2003 Rat Islands Tsunami 408 409 Construction of more than one model can reveal biases in a single model. Two types of comparisons 1 between those that are comceptually simailar and those that re different. In former case interested in how choice of numerical solver and discretisation effects results and the later can help determine the level of physical processs representation necessary to represent an observed data set. 410 411 Movinf to field data increases the gnereality and siginificance of svientifice evidence obatined. However we also significantly incerase the uncertainty of the validation experioment that may constrain the ability to make unequivacol statments. E.g. in bathymetry source condition friction. 412 413 Calibratino of the model is often used to compensate for uncertainty in the model inputs. Calibartion results in a further loss of experimental control as a unique solution may not exist. 414 415 verfication need to assess point data, spatially distributed data and bulk (lumped) data. 416 417 Synolakis et. al~\cite{synolakis07} detail two field events that have been previoulsy used to validate tsunami models, the Hokkaido-Nansei-Oki tsunami that occured around Okushiri Island, Japan on 2nd of July 1993 and the Rat Islands Tsunami that inundated the occured off the coast of Alaska on the 17th of November 2003. 418 419 420 inundation map only useful if mesh and topography resolution fine enough hard to measure what the model predicts how deep does inundation need to be for it to be visible during a field study 421 422 Notes: 423 Okushiri provides an example of extreme runup genereated from reflections and constructive interference resulting from local topography and bathymetry. Numerous point sites at which runup elevations were observed are available. The highest runup of 31.7 m in a valley north of Monai needs to be approximated with the numerical model. In addition, two tide gage records at Iwanai and Esashi need to be estimated. 424 425 426 427 Rat Island tsuanmi provides a good test for real-time forecasting models since tsnumai was recorded at three tsunameters. The test requires matching the propagation model data with the recordings to constrain the tsunami source model. The inundation model is to reproduce the tide gauge record at Hilo. 428 429 Patong Bay benchmark provides spatially distributed field data for comparison. 430 431 single experiment can refute model but cannot validate it. Need as many tests as possible to be confident in prediction. Question arises. How mnay should we do. 432 433 DO I SAY WE HAVE MUX @ FILES DESCRIBING SHAPE OF WAVE YES. MAKES CONSISTENT 434 435 Notes: * Model source developed independently of inundation data. 436 * Patong region was chosen because high resolution inundation map and bathymetry and topography data was available there 437 438 Geoscience Australia, in an open collaboration with the Mathematical Sciences Institute, The Australian National University, is developing a software application, ANUGA, to model the hydrodynamics of tsunamis, floods and storm surges. The open source software implements a finite volume central-upwind Godunov method to solve the non-linear depth-averaged shallow water wave equations. This paper investigates the veracity of ANUGA when used to model tsunami inundation. A particular aim was to make use of the comparatively large amount of observed data corresponding to the Indian ocean tsunmai event of December 2004, to provide a conditional assessment of the computational model's performance. Specifically a comparison is made between an inundation map, constructed from observed data, against modelled maximum inundation. This comparison shows that there is very good agreement between the simulated and observed values. The sensitivity of model results to the resolution of bathymetry data used in the model was also investigated. It was found that the performance of the model could be drastically improved by using finer bathymetric data which better captures local topographic features. The effects of two different source models was also explored. 439 440 different even types submarine mass failure generate larger events because of proximity more directional wave generation 441 442 even if data is available it is hard to access 443 444 article={ioualalen07, 445 title={Modeling the 26 December 2004 Indian Ocean tsunami: Case study of impact in Thailand}, 446 author=-{Ioualalen, M. and Asavanant, J. and Kaewbanjak, N. and Grilli, S.~T. and Kirby, J.~T. and Watts, P.}, 447 year={2007}, 448 journal ={ J. Geophys. Res.}, 449 volume={112}, 450 doi={http://dx.doi.org/10.1029/2006JC003850} 451 } 452 453 article={hirata06 454 title={The 2004 Indian Ocean tsunami: Tsunami source model from satellite altimetry}, 455 author={Hirata, K. and Satake, K. and Tanioka, Y. and Kuragano, T. and Hasegawa, Y. and Hayashi, Y. and Hamada, N.}, 456 journal={Earth, Planets and Space} 457 year={2006}, 458 volume={58}, 459 number={2}, 460 pages={195--201} 461 } 462 463 464 article={papadopoulos06 465 title={The large tsunami of 26 December 2004: Field observations and eyewitnesses accounts from Sri Lanka, Maldives Is. and Thailand}, 466 author={Gerassimos A. Papadopoulos, Riccardo Caputo, Brian McAdoo, Spyros Pavlides, Vassilios Karastathis, Fokaefs1, Katerina Orfanogiannaki1, and Sotiris Valkaniotis}, 467 journal={Earth, Planets and Space} 468 year={2006}, 469 volume={58}, 470 pages={233--241} 471 } 472 473 474 @InBook{asavanant08, 475 ALTauthor = {Asavanant, J. and Ioualalen, M. and Kaewbanjak, N. and Grilli, S.~T. and Watts, P. and Kirby, J.~T. and Shi, F.}, 476 ALTeditor = {}, 477 title = {Modeling, Simulation and Optimization of Complex Processes}, 478 chapter = {Numerical Simulation of the December 26, 2004: Indian Ocean Tsunami }, 479 publisher = { Springer Berlin Heidelberg}, 480 year = {2008}, 481 pages = {59--68}, 482 } 483 484 @article{grilli07, 485 author = {St\'{e}phan T. Grilli and Mansour Ioualalen and Jack Asavanant and Fengyan Shi and James T. Kirby and Philip Watts}, 486 title = {Source Constraints and Model Simulation of the December 26, 2004, Indian Ocean Tsunami}, 487 publisher = {ASCE}, 488 year = {2007}, 489 journal = {Journal of Waterway, Port, Coastal, and Ocean Engineering}, 490 volume = {133}, 491 number = {6}, 492 pages = {414-428}, 493 url = {http://link.aip.org/link/?QWW/133/414/1}, 494 doi = {10.1061/(ASCE)0733-950X(2007)133:6(414)} 495 } 410 In \cite{papadopoulos06} eyewitness accounts report 411 \emph{In Patong beach, most people observed at least two 412 waves. It is likely that the leading wave described in both 413 Sri Lanka and Maldives was not observed in Patong beach. 414 What people said is that the first sea motion was a retreat 415 of more than 100 m. A few minutes later the strong wave 416 arrived. Then, after another 5 or 10 min. one more wave attacked 417 but less violently than the first one. Nearly all the 418 interviewed persons reported that the tsunami inundation 419 in the Patong beach varied from 150 m to at least 750 m 420 (Fig. 16). One eyewitness reported inundation of only 20 421 m. As for the arrival time of the strong wave the eyewitnesses 422 do not agree. However, most reports concentrated 423 around 02:55 to 03:05 (09:55 to 10:05 local) which seems 424 to be a reliable description.} 425 426 FIXME(Ole): Need discussion of model results in this context.
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