HR: 16:30h
AN: S54A-03    [Abstracts]
TI: Rupture Process of Duzce Earthquake from joint analysis of SPOT, GPS, InSAR, strong- motion and teleseismic data: Supershear rupture speed and rapid variations
AU: * Konca, A
EM: ozgun@gps.caltech.edu
AF: Tectonic Observatory, California Institute of Technology Seismo lab 252-21, Pasadena, CA 91125, United States
AU: LePrince, S
EM: leprincs@caltech.edu
AF: Tectonic Observatory, California Institute of Technology Seismo lab 252-21, Pasadena, CA 91125, United States
AU: Avouac, J
EM: ozgun@gps.caltech.edu
AF: Tectonic Observatory, California Institute of Technology Seismo lab 252-21, Pasadena, CA 91125, United States
AU: Helmberger, D V
EM: helm@gps.caltech.edu
AF: Tectonic Observatory, California Institute of Technology Seismo lab 252-21, Pasadena, CA 91125, United States
AB: We have investigated the spatial and temporal evolution of the Duzce earthquake using the fault geometry and surface offsets obtained from the SPOT images, incorporated GPS and InSAR data as well as four strong-motion stations in the vicinity of the rupture. We focused on the rupture velocity to investigate whether super-shear rupture speeds occurred. No constant rupture velocity inversions were able to explain the available strong-motion data when the geodetic data was incorporated. The rupture accelerates up to supershear velocities on east side of the hypocenter, subsequently slows down. Rapid variations in rupture velocity is required to fit all the available datasets. The teleseismic data is consistent with the joint strong-motion and geodetic modeling of the event, with a time shift of about 2 seconds relative to their hand-picked arrival time. This implies that the slow start of the earthquake eminent from the strong-motion data is not observed at teleseismic distances. This problem leads to a more compact solution with major slip at and around the hypocentral area when only teleseismic data is used. Applying sub-pixel correlation of SPOT images acquired before and after the Duzce earthquake, we have mapped a continuous fault trace over 55 km; 15 km longer than the 40 km rupture length reported in the field studies. This observation sheds light on the abrupt eastern termination of the rupture discussed in prior geological and strong- motion surveys of the Duzce Earthquake. 4-segment fault geometry was constructed based on the fault map from the SPOT image analysis. In order to understand the effects of the improved fault geometry on the rapid estimation of earthquake properties, we compared the teleseismic inversion models from the satellite imagery based model with a one-segment model based on the Harvard CMT solution. The 4-segment model improves the fits to the teleseismic waveforms significantly, and gives better predictions of near-field ground motions.
DE: 7200 SEISMOLOGY
DE: 7209 Earthquake dynamics (1242)
DE: 7215 Earthquake source observations (1240)
DE: 7260 Theory
SC: Seismology [S]
MN: 2007 Fall Meeting