HR: 1340h
AN: OS23D-1361    [Abstracts]
TI: A Tsunami Induced by a Coastal Uplift During the 2003 Zemmouri Earthquake (Mw=6.8, Algeria): Modeling and Results
AU: Calbini, V
EM: calbini@eost.u-strasbg.fr
AF: Institut de Physique du Globe de Strasbourg - UMR7516 - EOST, 5, Rue Rene Descartes, Strasbourg, 67084 France
AU: * Alasset, P
EM: pierrejean.alasset@eost.u-strasbg.fr
AF: Institut de Physique du Globe de Strasbourg - UMR7516 - EOST, 5, Rue Rene Descartes, Strasbourg, 67084 France
AU: Hebert, H
EM: helene.hebert@cea.fr
AF: Laboratoire de Detection et de Geophysique, CEA, BP12, Bruyeres le Chatel, 91680 France
AU: Maouche, S
EM: said\_maouche@yahoo.fr
AF: Centre de Recherche en Astrophysique et Geophysique (CRAAG), Bouzareah, Alger, BP 63 Algeria
AU: Meghraoui, M
EM: mustapha@eost.u-strasbg.fr
AF: Institut de Physique du Globe de Strasbourg - UMR7516 - EOST, 5, Rue Rene Descartes, Strasbourg, 67084 France
AB: A strong tsunami with sea disturbances observed along the Algerian coast, but with significant damage mainly in the Balearic Islands (Spain) harbors, affected the western Mediterranean during the 2003 Zemmouri earthquake (Mw 6.8, Algeria). An average regional uplift of 0.55m was measured along the shoreline in the epicentral area. Field observations, mainshock and aftershocks studies and characteristics concur for a $ \sim $ 55-km-long trending rupture, NE-SW trending, dipping SE and with thrust mechanism. The seismotectonic parameters indicate a surface deformation with 7 to 8-km-deep hypocenter and a possible fault outcrop offshore between 5 and 15 km from the shoreline. Different tide gauges located in the western Mediterranean Coast indicate and average of 0.4 m of sea level change with a maximum of 2m in the Balearic Islands. We generated high resolution bathymetry grids from the Algerian coasts to the Balearic Islands coasts in order to test different seismic sources (with different fault rupture location, strike and dip) and model the tsunami initiation and propagation. We use a Crank-Nicolson numerical schema with a finite difference method and the modeling is supported to the Okada Elastic model. We also highlight the different factors responsible of waves amplification around the Balearic coasts. The best fit between synthetic and real data (tide gauges, GPS leveling and coastal uplift as compared to run-up values) are obtained for a thrust rupture comparable with the earthquake fault inferred from seismotectonic studies and located within 15 km offshore. This study presents the first results and modeling of a major tsunami recorded in the western Mediterranean Sea.
DE: 7223 Seismic hazard assessment and prediction
DE: 4564 Tsunamis and storm surges
SC: Ocean Sciences [OS]
MN: 2004 AGU Fall Meeting