HR: 0830h
AN: S21E-0375    [PDF]
TI: Transversely Isotropic D'' shear velocity structure beneath Central America studied using waveform inversion
AU: * Kawai, K
EM: kenji@eps.s.u-tokyo.ac.jp
AF: ept. of Earth and Planetary Science Graduate School of Science University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033 Japan
AU: Takeuchi, N
EM: takeuchi@seismo.berkeley.edu
AF: Berkeley Seismological Lab UC Berkeley, 215 McCone Hall, Berkeley, CA 94720
AU: Geller, R J
EM: bob@eps.s.u-tokyo.ac.jp
AF: ept. of Earth and Planetary Science Graduate School of Science University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033 Japan
AB: We (Kawai et al., 2002) have developed the methodology and software for accurately and efficiently computing synthetic seismograms for transversely isotropic (TI) laterally homogeneous media using the Direct Solution Method (DSM). We apply these techniques to study the TI shear velocity structure in the D'' shear region beneath Central America using waveform inversion. This region is of great interest because of the existence of the D'' discontinuity (Lay \& Helmberger 1983) and anisotropy (e.g., Kendall \& Silver, 1996). The velocity structure has been studied by many research groups (e.g. Ding \& Helmberger, 1997). Ding \& Helmberger suggested an isotropic D'' shear velocity structure model (SDH model), using the transverse component of broadband network seismograms in USA and Canada. However, they pointed out that the radial component data could not be explained by the SDH model, especially at epicentral distances $>$ 85 degrees. We investigate the extent to which a TI shear velocity structure beneath Central America can explain both the radial- and transverse-component data.
UR: http://www.eps.s.u-tokyo.ac.jp
DE: 7200 SEISMOLOGY
DE: 7207 Core and mantle
SC: Seismology [S]
MN: 2003 Fall Meeting