HR: 1340h
AN: S13D-1076    [Abstracts]
TI: Fault location and source process of the 2003 Boumerdes, Algeria, earthquake inferred from geodetic and strong motion data.
AU: Semmane, F
EM: Fehti.Semmane@ujf-grenoble.fr
AF: LGIT, Universite Joseph Fourier and CNRS, BP 53, Grenoble, 38041 France
AU: Semmane, F
EM: Fehti.Semmane@ujf-grenoble.fr
AF: CRAAG, Observatoire d'Alger, BP 63 Bouzareah, Alger, 0000 Algeria
AU: * Campillo, M
EM: Michel.Campillo@ujf-grenoble.fr
AF: LGIT, Universite Joseph Fourier and CNRS, BP 53, Grenoble, 38041 France
AU: Cotton, F
EM: Fabrice.Cotton@ujf-grenoble.fr
AF: LGIT, Universite Joseph Fourier and CNRS, BP 53, Grenoble, 38041 France
AB: The Boumerdes earthquake occurred on a fault which precise location, offshore the algerian coast, was unknown. Geodetic data consist of GPS measurements, levelling points and coastal uplifts. They are first used to determine the absolute position of the fault. We performed a series of inversions assuming different positions and chose the model giving the smallest misfit. According to this analysis, the fault emerge at about 15 km offshore. Accelerograms are then used to infer the space-time history of rupture on the fault plane using a two-step inversion in the spectral domain. The observed strong motion records are in good agreement with the synthetics for the fault location inferred from geodetic data. The fault plane ruptured for about 16 seconds. The slip distribution on the fault indicates one asperity north-west of the hypocenter with a maximum slip amplitude larger than 2.5 m. Another asperity with slightly smaller slip amplitude is located south-east of the hypocenter. The rupture seems to stop its propagation westward when it encounters the Thenia fault, a structure almost perpendicular to the main fault. We computed the spatial distribution of ground motion predicted by this fault model and compared it with the observed damages.
DE: 7230 Seismicity and seismotectonics
DE: 7209 Earthquake dynamics and mechanics
DE: 7212 Earthquake ground motions and engineering
DE: 7215 Earthquake parameters
SC: Seismology [S]
MN: 2004 AGU Fall Meeting