HR: 0800h
AN: U11A-0816    [Abstracts]
TI: Impact of the 2004 Sumatra tsunami in the SW Indian Ocean: numerical modeling on La Réunion island
AU: * Hebert, H
EM: helene.hebert@cea.fr
AF: Laboratoire de D‚tection et de G‚ophysique CEA/DASE, BP 12, BruyŠres le Chƒtel, 91680 France
AU: SLADEN, A
EM: anthony.sladen@cea.fr
AF: Laboratoire de D‚tection et de G‚ophysique CEA/DASE, BP 12, BruyŠres le Chƒtel, 91680 France
AB: The great 2004 Sumatra tsunami provoked considerable damage in the near field as well as on remote coastlines of the Indian Ocean. In this aspect, La Réunion island was only moderately struck, but local disturbances were nevertheless significant enough to break moorings of one container ship anchored in the Pointe des Galets (Port Est) harbor twice, surprisingly at several hours interval. A field survey organized in March (Okal, Sladen, 2005) revealed that the run-up in the R‚union Island were ranging from 1 to 2.3 m all along the coastline, with largest values obtained in the western part of the Island, thus in the opposite direction of the arrival azimut of the waves. In addition an analog paper tide gauge record is available in La Pointe des Galets harbor, showing a long-lasting perturbation (> 12 hours) of the sea level with amplitudes hardly larger than 50 cm. This record may not account for the actual wave heights, but the information on the wave train is quite useful. We use here a set of bathymetric data refined close to the La Réunion island shores in order to explain the different observations and to numerically model the tsunami impact in detail in the harbors. Using several different earthquake sources, we explain the temporal behavior of the waves in the harbors, and study the efficiency of regional bathymetric features to trap or scatter the tsunami energy. We analyze the relative wave amplitudes computed, providing preliminary elements to future studies of tsunami hazard in La Réunion.
DE: 4534 Hydrodynamic modeling
DE: 4564 Tsunamis and storm surges
DE: 7240 Subduction zones (1207, 1219, 1240)
DE: 9340 Indian Ocean
SC: Union [U]
MN: Fall Meeting 2005