HR: 1330h
AN: S52A-0129    [PDF]
TI: BROADBAND GROUND MOTION SYNTHESIS OF THE 1999 TURKEY EARTHQUAKES BASED ON: 3-D VELOCITY INVERSION, FINITE DIFFERENCE CALCULATIONS AND EMPRICAL GREENS FUNCTIONS
AU: * Gok, R
EM: gok1@llnl.gov
AF: Lawrence Livermore National Laboratory, 7000 East Avenue L-206, Livermore, CA 94550 United States
AU: Kalafat, D
EM: kalafato@boun.edu.tr
AF: Bogazici University Kandilli Observatory and Earthquake Research Institute, Cengelkoy, Istanbul, 81220 Turkey
AU: Hutchings, L
EM: hutchings2@llnl.gov
AF: Lawrence Livermore National Laboratory, 7000 East Avenue L-206, Livermore, CA 94550 United States
AB: We analyze over 3,500 aftershocks recorded by several seismic networks during the 1999 Marmara, Turkey earthquakes. The analysis provides source parameters of the aftershocks, a three-dimensional velocity structure from tomographic inversion, an input three-dimensional velocity model for a finite difference wave propagation code (E3D, Larsen 1998), and records available for use as empirical Green's functions. Ultimately our goal is to model the 1999 earthquakes from DC to 25 Hz and study fault rupture mechanics and kinematic rupture models. We performed the simultaneous inversion for hypocenter locations and three-dimensional P- and S- wave velocity structure of Marmara Region using SIMULPS14 along with 2,500 events with more than eight P- readings and an azimuthal gap of less than 180\deg. The resolution of calculated velocity structure is better in the eastern Marmara than the western Marmara region due to the dense ray coverage. We used the obtained velocity structure as input into the finite difference algorithm and validated the model by using M $<$ 4 earthquakes as point sources and matching long period waveforms (f $<$ 0.5 Hz). We also obtained Mo, fc and individual station kappa values for over 500 events by performing a simultaneous inversion to fit these parameters with a Brune source model. We used the results of the source inversion to deconvolve out a Brune model from small to moderate size earthquakes (M $<$ 4.0) to obtain empirical Green's function (EGF) for the higher frequency range of ground motion synthesis (0.5 $<$ f $>$ 25 Hz). We additionally obtained the source scaling relation (energy-moment) of these aftershocks. We have generated several scenarios constrained by a priori knowledge of the Izmit and Duzce rupture parameters to validate our prediction capability.
DE: 7209 Earthquake dynamics and mechanics
DE: 7218 Lithosphere and upper mantle
DE: 7223 Seismic hazard assessment and prediction
SC: Seismology [S]
MN: 2003 Fall Meeting