HR: 1330h
AN: U53A-04    [Abstracts]
TI: Estimate the Sumatra Earthquake Source Based on Satellite Observations and an Ocean-Bottom-Pressure Tsunami Model
AU: * Song, Y
EM: Tony.Song@jpl.nasa.gov
AF: Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 United States
AU: Fu, L
EM: llf@pacific.jpl.nasa.gov
AF: Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 United States
AU: Zlotnicki, V
EM: vz@pacific.jpl.nasa.gov
AF: Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 United States
AU: Shum, C
EM: cksum@osu.edu
AF: Ohio State University, 1960 Kenny Road, Columbus, OH 43210 United States
AU: Yi, Y
AF: Ohio State University, 1960 Kenny Road, Columbus, OH 43210 United States
AU: Ji, C
EM: jichen@gps.caltech.edu
AF: California Institute of Technology, 1200 E. California Blv, Pasadena, CA 91125 United States
AB: Several satellite radar altimeters and tide gauges have observed the Indian Ocean tsunami triggered by the M9.0 earthquake off the west coast of northern Sumatra, Indonesia, on December 26. These observations are unique and of tremendous value for testing tsunami prediction models. Earthquake tsunamis are difficult to predict because the exact force that strikes the ocean bottom water which generates a tsunami is difficult to measure. Even if the force is measured, conventional tsunami wave models are not designed to utilize the measured information for better predictions. Consequently, an unacceptable 75 percent false alarm rate has prevailed. Here we show that by applying the earthquake data as ocean-bottom-pressure (OBP) forcing in a non-Boussinesq three-dimensional ocean model, we can simulate the Indian Ocean tsunami better in comparison with the satellite-observed sea-surface-heights and tide gauge observed waves. The OBP force is consistent with seismic estimates and theories [Ji et al., 2002]. It is also found that the tsunami surface wave is not equivalent to the corresponding OBP, which is much larger than previously thought after being converted into water thickness. The sensitivity study, verified by the satellite and other observations, indicates that the ocean-bottom-pressure variation caused by the ground motion is the key to the successful prediction of earthquake tsunamis.
DE: 4263 Ocean prediction
DE: 4275 Remote sensing and electromagnetic processes (0689)
DE: 4500 OCEANOGRAPHY: PHYSICAL
DE: 4564 Tsunamis and storm surges
DE: 7230 Seismicity and seismotectonics
SC: Union [U]
MN: 2005 Joint Assembly