HR: 15:10h
AN: S33D-07    [Abstracts]
TI: A new global PKP data set to study the Earth's deep interior
AU: Chevrot, S
EM: Sebastien.Chevrot@cnes.fr
AF: Laboratoire de Dynamique Terrestre et Planetaire, CNRS UMR5562, Observatoire Midi Pyrenees, 14,Ave E. Belin, Toulouse, 31400 France
AU: * Garcia, R
EM: garcia@ipgp.jussieu.fr
AF: Etudes Spatiales et Planetologie, Institut de Physique du Globe de Paris, 4, ave de Neptune, Saint Maur, 94107 France
AU: Tkalcic, H
EM: hrvoje@gnem9.llnl.gov
AF: Earth Science Division, Lawrence Livermore National Laboratory, L-206, P.O. Box 808, Livermore, CA CA 94550 United States
AB: PKP waveforms are the main source of information regarding lowermost mantle and core seismological structures. An extension of our previously developed Simulated Annealing algorithm to analyze body waves is presented. It allows us to resolve the interference between the different PKP phases and their corresponding depth phases (pPKP and sPKP), which makes possible to process shallow earthquakes previously discarded, and thus to improve the sampling of the deep Earth. The algorithm is applied to various PKP waveform data sets in order to retrieve differential travel times and amplitude ratios of the core phases, and to demonstrate its efficiency. We present a first order analysis of differential travel times, amplitude ratios and waveforms of this new data base of PKP core phases in order to constrain the inner core seismic anisotropy, attenuation and deep structure. The introduction of shallow event data confirms the hemispherical pattern of the inner core anisotropy and the increase of the inner core quality factor with depth. An anti-correlation is found at all epicentral distances between differential travel time residuals and amplitude ratios. This anti-correlation can only be explained by a high attenuation of fast rays inside the inner core, produced by inner core fabric. Amplitude ratios and waveforms of core phases are also analyzed tin order to detect inner core discontinuities below the inner core boundary.
DE: 3260 Inverse theory
DE: 5144 Wave attenuation
DE: 7203 Body waves
DE: 7207 Core (1212, 1213, 8124)
DE: 8115 Core processes (1213, 1507)
SC: Seismology [S]
MN: Fall Meeting 2005