Assessment of Tsunami Modeling Using Satellite Altimetry and Tide Gauges
Manman Zhang(1) , Yuhe Tony Song(2) , Alexander Braun(3) , C.K. Shum(1) , and Yuchan Yi(1)
Ohio State University,
125 S. Oval Mall,
Columbus, Ohio, 43210,
(2) California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109, United States
(3) University of Calgary, 2500 University Drive NW, Calgary, AB, T2N 1N4, Canada
The 26 December 2004 Indian Ocean tsunami is triggered by the largest earthquake in 40 years, the Mw=9.3 Sumatra-Andaman undersea earthquake. The resulting earthquake tsunami of this magnitude is the first to occur since the advent of both digital seismometry and multiple satellite radar altimetry. Both have independently recorded the event, but from different physical aspects. The strong tsunami is also detected by world-wide tide gauges significantly away from the source. The seismic data have been used to estimate the earthquake fault parameters and the satellite observed tsunami waves are used to determine the initial sea-surface-displacement as well as the effects of 1300 km seafloor ruptures with a duration of ~40 minutes triggered by the great Sumatra-Andaman earthquake. Here we show that these two data sets provide consistent tsunami source, using independent methodologies of seismic-inversion and ocean general circulation modeling (OGCM), and provide an analysis of the OGCM tsunami model versus other tsunami models. Cross-examining the two independent results confirms that the earthquake-induced bottom-pressure-force is the most important condition that controls the tsunami strength, while the geometry and the rupture velocity of the tectonic plane determine the spatial pattern of the tsunami. The use of OGCM accounts for ocean circulations and the sea floor forcing mechanism used allow quantification of the effects of both horizontal and vertical sea floor uplifts. We further use multiple satellite altimetry and world tide gauges to compare and diagnose the available tsunami models, including the OGCM tsunami model. The developed methodology offers an improved capability for tsunami modeling and potential more accurate predictions.