Numerical Simulation of the December 26, 2004 Indian Ocean Tsunami using a Higher-order Boussinesq Model (original) (raw)
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Numerical Simulation of the December 26, 2004 Indian Ocean Tsunami using a Boussinesq model
2004
We provide preliminary calculations of wave generation, propagation and inundation for the December 26, 2004 Indian Ocean tsunami. Calculations are based on Boussinesq model FUNWAVE and are carried out on a Cartesian grid with spatial resolution comparable to 2 minutes in latitude and longitude. Initial conditions are provided by the TOPICS model and are based on estimates of ground motion
Numerical modeling of the 26th December 2004 India Ocean tsunami at Andaman and Nicobar Islands
Journal of Coastal Conservation, 2008
A numerical simulation of the 26th December 2004 Indian Ocean tsunami for the Andaman and Nicobar Islands case study is presented. The simulation approach is based on a fully nonlinear Boussinesq tsunami propagation model and included an accurate computational domain and a robust coseismic source. The simulation is first confronted to available tide gauge and run-up observations. The agreement between observations and the predicted wave heights allowed a reasonable validation of the simulation. As a result a full picture of the tsunami impact is provided over the entire coastal zone of Andaman and Nicobar Islands. The processes responsible for coastal vulnerability are discussed.
Source Constraints and Model Simulation of the December 26, 2004, Indian Ocean Tsunami
Journal of Waterway Port Coastal and Ocean Engineering-asce, 2007
The December 26, 2004 tsunami was perhaps the most devastating tsunami in recorded history, causing over 200,000 fatalities and widespread destruction in countries bordering the Indian Ocean. It was generated by the third largest earthquake on record ͑M w = 9.1-9.3͒ and was a truly global event, with significant wave action felt around the world. Many measurements of this event were made with seismometers, tide gauges, global positioning system stations, and a few satellite overpasses. There were numerous eyewitness observations and video digital recordings of coastal tsunami impact, as well as subsequent coastal field surveys of runup and flooding. A few ship-based expeditions also took place in the months following the event, to measure and map seafloor disturbances in the epicenter area. Based on these various data sets, recent seismic analysis estimates of rupture propagation speed, and other seismological and geological constraints, we develop a calibrated tsunami source, in terms of coseismic seafloor displacement and rupture timing along 1,200 km of the Andaman-Sunda trench. This source is used to build a numerical model of tsunami generation, propagation, and coastal flooding for the December 26, 2004 event. Frequency dispersion effects having been identified in the deep water tsunami wavetrain, we simulate tsunami propagation and coastal impact with a fully nonlinear and dispersive Boussinesq model ͑FUNWAVE͒. The tsunami source is specified in this model as a series of discrete, properly parameterized, dislocation source segments ͓Okada, 1985, Bull. Seismol. Soc. Am., 75͑4͒, 1135-1154͔, triggered in a time sequence spanning about 1,200 s. ETOPO2's bottom bathymetry and land topography are specified in the modeled ocean basin, supplemented by more accurate and denser data in selected coastal areas ͑e.g., Thailand͒. A 1 min grid is used for tsunami simulations over the Indian Ocean basin, which is fine enough to model tsunami generation and propagation to nearshore areas. Surface elevations simulated in the model agree well, in both amplitude and timing, with measurements at tide gauges, one satellite transect, and ranges of runup values. These results validate our tsunami source and simulations of the December 26, 2004 event and indicate these can be used to conduct more detailed case studies, for specific coastal areas. In fact, part of the development of our proposed source already benefitted from such regional simulations performed on a finer grid ͑15 s͒, as part of a Thailand case study, in which higher frequency waves could be modeled ͑Ioualalen et al. 2007, J. Geophys. Res., 122, C07024͒. Finally, by running a non-dispersive version of FUNWAVE, we estimate dispersive effects on maximum deep water elevations to be more than 20% in some areas. We believe that work such as this, in which we achieve a better understanding through modeling of the catastrophic December 26, 2004 event, will help the scientific community better predict and mitigate any such future disaster. This will be achieved through a combination of forecasting models with adequate warning systems, and proper education of the local populations. Such work must be urgently done in light of the certitude that large, potentially tsunamogenic, earthquakes occur along all similar megathrust faults, with a periodicity of a few centuries.
Numerical Modeling of the Global Tsunami
2005
A new model for the global tsunami computation is constructed. It includes a high order of approximation for the spatial derivatives. The boundary condition at the shore line is controlled by the total depth and can be set either to runup or to the zero normal velocity. This model, with spatial resolution of one minute, is applied to the tsunami of 26 December 2004 in the World Ocean from 80! S to 69! N. Because the computational domain includes close to 200 million grid points, a parallel version of the code was developed and run on a supercomputer. The high spatial resolution of one minute produces very small numerical dispersion even when tsunamis wave travel over large distances. Model results for the Indonesian tsunami show that the tsunami traveled to every location of the World Ocean. In the Indian Ocean the tsunami properties are related to the source function, i.e., to the magnitude of the bottom displacement and directional properties of the source. In the Southern Ocean s...
Modeling the 26 December 2004 Indian Ocean tsunami: Case study of impact in Thailand
2007
Indian Ocean tsunami stressed the need for assessing tsunami hazard in vulnerable coastal areas. Numerical modeling is but one important tool for understanding past tsunami events and simulating future ones. Here we present a robust simulation of the event, which explains the large runups and destruction observed in coastal Thailand and identifies areas vulnerable to future tsunamis, or safer for reconstruction. To do so, we use an accurate tsunami source, which was iteratively calibrated in earlier work to explain the large-scale tsunami features, and apply it over a computational domain with a finer grid and more accurate coastal bathymetry in Thailand. Computations are performed with a well-validated numerical model based on fully nonlinear and dispersive Boussinesq equations (FUNWAVE) that adequately models the physics of tsunami propagation and runup, including dissipation caused by bottom friction and wave breaking. Simulated runups in Thailand reproduce field observations with a surprising degree of accuracy, as well as their high degree of along-coast variation: a 92% correlation is found between (58) runup observations and computations, while the model explains 85% of the observed variance; overall, the RMS error is approximately 1 m or 17% of the mean observed runup value (skill of the simulation). Because we did not use runup observations to calibrate our coseismic tsunami source, these results are robust, and thus provide a uniquely accurate synoptic prediction of tsunami impact along the Andaman coast of Thailand, including those areas where no observations were made.
2012
The March 11, 2011 M9 Tohoku-Oki Earthquake, which is believed to be the largest event recorded in Japanese history, created a major tsunami that caused numerous deaths and enormous destruction on the nearby Honshu coast. Various tsunami sources were developed for this event, based on inverting seismic or GPS data, often using very simple underlying fault models (e.g., . Tsunami simulations with such sources can predict deep water and far-field observations quite well, but coastal impact is not as well predicted, being over-or under-estimated at many locations. In this work, we developed a new tsunami source, similarly based on inverting onshore and offshore geodetic (GPS) data, but using 3D Finite Element Models (FEM) that simulate elastic dislocations along the plate boundary interface separating the stiff subducting Pacific Plate, and relatively weak forearc and volcanic arc of the overriding Eurasian plate. Due in part to the simulated weak forearc materials, such sources produce significant shallow slip along the updip portion of the rupture near the trench (several tens of meters).
Journal of applied mechanics, 2007
Numerical simulation of Tsunami propagation has been carried out based on four algorithms of wave dynamical equation. Besides non-linear shallow water equation which is common for the simulation, dispersive wave model (i.e. Boussinesq-type equations) is a challenge to make more reasonable model while taking care of the low computation cost. This paper discussed numerical simulation results of tsunami propagation model based on dispersive and non-dispersive models. Satellite image data is used to compare the numerical results with real field sea levels data of tsunami. Simulation results show that the dispersive models give better prediction but still need high computation cost while non-dispersive one give consistent result.
Ocean Modelling, 2017
Accurate numerical simulation of the far-field tsunami caused by the 2011 Tohoku earthquake, including the effects of Boussinesq dispersion, seawater density stratification, elastic loading, and gravitational potential change, Ocean Modelling (2017),