HR: 11:50h
AN: S32B-07    [Abstracts]
TI: 3D Hybrid Numerical Modeling of Seismic Motion in Sedimentary Valleys due to a Dynamic Source Model
AU: Kristek, J
EM: kristek@fmph.uniba.sk
AF: Faculty of Mathematics, Physics and Informatics, Comenius University, Mlynska dolina F1, Bratislava, 842 48 Slovakia (Slovak Republic)
AU: * Moczo, P
EM: moczo@fmph.uniba.sk
AF: Faculty of Mathematics, Physics and Informatics, Comenius University, Mlynska dolina F1, Bratislava, 842 48 Slovakia (Slovak Republic)
AU: Galis, M
EM: mgalis@fmph.uniba.sk
AF: Faculty of Mathematics, Physics and Informatics, Comenius University, Mlynska dolina F1, Bratislava, 842 48 Slovakia (Slovak Republic)
AU: Bard, P
EM: Pierre-Yves.Bard@obs.ujf-grenoble.fr
AF: LGIT, Universite Joseph Fourier, BP53, Grenoble, 38041 France
AB: We have developed a 3D hybrid modeling technique based on the combination of the finite-element (FE) and finite-difference (FD) methods to simulate dynamic rupture propagation on a fault, seismic wave radiation and propagation in a heterogeneous viscoelastic medium with realistic model of the attenuation. In an arbitrarily shaped part of the whole computational region, the 2nd-order displacement FE method is used to simulate rupture propagation on a possibly non-planar fault. The FE part of the region may also have a non-planar free surface. The rest of the computational region is solved by the 4th-order velocity-stress staggered-grid FD scheme. The schemes may share the same time step while the major part of the model for the seismic wave propagation away from the radiating fault is efficiently covered by the grid with twice larger spatial grid spacing. The FE and FD schemes communicate at each time level in the transition zone in which both spatial grids overlap. The TSN (traction-at-split-node) method (Andrews 1999) is used for modeling the rupture propagation. The numerical tests show very good accuracy of the hybrid modeling. We apply the method to model earthquake ground motions in the Grenoble Valley, France, due to two hypothetical earthquakes on the Belledonne fault. We analyze the effect of different positions of the earthquake hypocenter on the ground motion in the sediment valley. We also compare the motion due to dynamic rupture on the fault with that produced by the equivalent double-couple point source for both considered earthquakes.
DE: 7260 Theory and modeling
DE: 7209 Earthquake dynamics and mechanics
DE: 7212 Earthquake ground motions and engineering
SC: Seismology [S]
MN: 2004 AGU Fall Meeting