HR: 1330h
AN: S52A-0131    [PDF]
TI: Stochastic Strong Ground Motion Simulation of the 7 September 1999 Athens (Greece) Earthquake
AU: * Roumelioti, Z
EM: zroum@lemnos.geo.auth.gr
AF: Department of Geophysics, Aristotle University of Thessaloniki, P.O. Box 352-1, Thessaloniki, 54124 Greece
AU: Kiratzi, A
EM: Kiratzi@geo.auth.gr
AF: Department of Geophysics, Aristotle University of Thessaloniki, P.O. Box 352-1, Thessaloniki, 54124 Greece
AU: Theodoulidis, N
EM: ntheo@itsak.gr
AF: Institute of Engineering Seismology and Earthquake Engineering, P.O. Box 53, Thessaloniki, 55102 Greece
AB: The stochastic method for finite faults is applied to simulate the strong ground motion from the 7 September 1999, M 5.9 Athens earthquake. The method includes descritization of the fault plane into certain number of subfaults, each of which is assigned an $\omega^{2}$ spectrum. A slip distribution model, derived from previous studies of this earthquake, is used to specifically account for the source effect. The contributions from all subfaults are then empirically attenuated to the observation sites, where they are summed to produce the synthetic acceleration time history. The method is first calibrated against its ability to reproduce the recordings of 19 strong-motion stations, at epicentral distances ranging from 16 to 61 km. The calibrated model is then used to calculate synthetics at a large number of grid points covering the area around the fault plane. Simulated peak values are subsequently used to produce synthetic peak ground acceleration and spectral acceleration maps at hard rock conditions. Both the peak ground acceleration and spectral acceleration maps imply energy directivity towards east, where most of the damage was concentrated. The directivity effect is most prominent at large periods ($>$2 sec) and in the frequency range 0.2 - 0.3 sec. Independent geotechnical studies showed considerable site-effect at periods $<$0.5 sec within the meizoseismal area. This result, coupled with the results of the present study, imply that the damage distribution pattern of the 1999 Athens earthquake can be explained by the destructive combination of two factors: the source directivity and the site effect.
DE: 7200 SEISMOLOGY
DE: 7212 Earthquake ground motions and engineering
SC: Seismology [S]
MN: 2003 Fall Meeting