INDIAN OCEAN TSUNAMI GENERATION AND PROPAGATION FROM MODELING AND OBSERVATIONS

The Sumatra tsunami was the most devastating tsunami in modern history. It is also rapidly becoming the most studied tsunami in history. Data from tide gauges, satellite altimetry, field surveys help to put together the puzzle of the Sumatra tsunami picture. Substantial uncertainties, however, still exist about the tsunami source, tsunami propagation and impact, despite the wealth of data already collected from observations and various model results. This is due to problems with quality and spatial distribution of available tsunami measurements. The tsunami data from the near-source area are mostly from field surveys, very few instrumental data are available. The data from the far-field may be difficult to interpret in terms of the tsunami source characteristics. The lack of high-quality bathymetry for most of the Indian Ocean coasts may make model comparison with tide gage data ambiguous and inconclusive. We present results of modeling efforts that use numerical simulations to interpret the Sumatra tsunami data. Satellite altimetry, tide gauges and runup measurements are used to constrain the model and understand the tsunami source extend and magnitude. Lessons for tsunami real-time forecast and warning are also discussed.