HR: 1340h
AN: S43A-1059    [Abstracts]
TI: A Comparison Between Dc'-values Obtained From a Dynamic Rupture Model and Waveform Inversion
AU: * Yasuda, T
EM: tyasuda@eri.u-tokyo.ac.jp
AF: Earthquake Research Institute, University of Tokyo, Yayoi 1-1-1 Bunkyo-ku, Tokyo, 113-0032 Japan
AU: Yagi, Y
EM: yagi-y@arsia.geo.tsukuba.ac.jp
AF: Graduate School of Life and Environmental Sciences, University of Tsukuba, Tennoudai 1-1-1, Tsukuba, 305-8572 Japan
AU: Mikumo, T
EM: mikumo@ollin.igeofcu.unam.mx
AF: Institute de Geofisica, Universidad Nacional Autonoma de Mexico, Ciudad Universitaria, Mexico D.F., Mexico, 04510 Mexico
AU: Miyatake, T
EM: miyatake@eri.u-tokyo.ac.jp
AF: Earthquake Research Institute, University of Tokyo, Yayoi 1-1-1 Bunkyo-ku, Tokyo, 113-0032 Japan
AB: Slip-weakening behavior of shear stress on earthquake faults plays a critical role in the dynamic part of the rupture process and hence on strong ground motions during large earthquakes. Accordingly, it is important in rupture dynamics to study the critical slip-weakening distance at which the shear stress drops to the frictional stress level. We investigate the validity of a method for estimating the critical slip-weakening distance (Dc), which was proposed by Mikumo et al. [2003], for a dynamic rupture model of a recent earthquake. Firstly, we construct a hypothetical dynamic rupture model for an earthquake, with a uniform Dc distribution. As a second step, we generate the synthetic waveforms from this model for a number of recording stations. Then, we carry out kinematic inversion of the waveforms to obtain the mean slip rate time function on each subfault. Following Mikumo et al. [2003], we try to calculate Dc' from the mean slip rate time functions to see if the assigned Dc-value could be correctly recovered. We also investigate the effect from rupture propagation on subfaults, which has not been taken into consideration in the previous studies [e.g. Mikumo et al., 2003], and the effects from waveform inversion and bandpass filtering on the estimate of Dc. We found that Dc' calculated from the `dynamically generated mean' slip rate functions deviates, to some extent, from the assumed value of 25cm, and also that the rupture propagation effects inside the subfaults causes an apparent correlation between Dc and final slip. Dc' obtained from the waveform inversion are relatively consistent with Dc' calculated from the `dynamically generated mean' slip rate functions. As mentioned in Spudich and Guatteri [2004] and Guatteri and Spudich [2000], the effect of Dc on the waveforms in high frequency range seems to be quite large. If this information were retained in the inversion process, and if we could refine our method of estimation, it would not be impossible to correct the obtained Dc'-values for the estimate of Dc distribution on the fault.
DE: 7209 Earthquake dynamics (1242)
DE: 7260 Theory
SC: Seismology [S]
MN: Fall Meeting 2005