Threedimensional modeling of nearfault ground motions with nonplanar rupture models and topography: Case of the 2004 Parkfield earthquake
Gallovic, Frantisek, Martin Käser, Jan Burjanek, and Ch. Papaioannou (2010),
Threedimensional modeling of nearfault ground motions with nonplanar rupture models and topography: Case of the 2004 Parkfield earthquake,
J. Geophys. Res., 115, B03308, doi:10.1029/2008JB006171.
 Abstract
 We study the applicability of deterministic strong ground motion simulations at very nearfault distances for a subvertical strike slip fault model corresponding to the 2004 M6 Parkfield, California, earthquake. Theoretical modeling based on such a model under the assumptions of a planar rupture and 1D medium show that, as a consequence of the Swave radiation pattern, the particle motion for such close stations should be almost linear in the faultnormal direction, having faultparallel (FP) and vertical (V) components almost zero. However, as shown on the Parkfield earthquake recordings, observed particle motions are rather circular and peak velocities have relatively large values at FP and V components, even comparable to that at faultnormal (FN) component. We investigate which more realistic features can explain the controversy and thus have to be included in the modeling, namely: a nonplanar fault, realistic threedimensional (3D) medium, the topography of the area. We test and quantify these hypotheses using the discrete wavenumber and the discontinuous Galerkin modeling methods applying 1D and 3D velocity structures, respectively, and two nonplanar rupture models. We compare the synthetic and observed particle motions and peak velocity ratios and conclude that deviations from a planar rupture geometry in reasonable bounds for the Parkfield fault and the influence of topography only partially explain the behavior of the observed seismograms. On the contrary, the heterogeneous 3D velocity structure significantly reduces the synthetic peak ratios to values closer to one and provide rather circular particle motions. Therefore, either nonplanar rupture in 1D modeling or 3D velocity medium are to be included in the simulations to obtain realistic estimates of ground motions at nearfault distances.
 BibTeX

@article{id1369,
author = {Frantisek Gallovic and Martin K{\"a}ser and Jan Burjanek and Ch. Papaioannou},
journal = {J. Geophys. Res.},
pages = {B03308},
title = {{Threedimensional modeling of nearfault ground motions with nonplanar rupture models and topography: Case of the 2004 Parkfield earthquake}},
volume = {115},
year = {2010},
doi = {10.1029/2008JB006171},
}
 EndNote

%0 Journal Article
%A Gallovic, Frantisek
%A Käser, Martin
%A Burjanek, Jan
%A Papaioannou, Ch.
%D 2010
%V 115
%J J. Geophys. Res.
%P B03308
%T Threedimensional modeling of nearfault ground motions with nonplanar rupture models and topography: Case of the 2004 Parkfield earthquake