HR: 0830h
AN: S41E-0129    [PDF]
TI: Pseudospectral Modeling in Whole Earth Models: Apparent Attenuation and Anisotropy from Small Scale Heterogeneity
AU: * Cormier, V F
EM: vernon.cormier@uconn.edu
AF: University of Connecticut, Department of Geology and Geophysics, Storrs, CT 06269-2045 United States
AB: Broadband (0.01 to 1 Hz), 3-component, seismograms are synthesized to 180\deg range by 2-D pseudospectral methods in several models having statistically described heterogeneity in the mantle. Considered models include gradient increases in RMS heterogeneity power in the lowermost (D$^{''}$ region) of the mantle, and bi-modal models of D$^{''}$ consisting of either two-phases (partial melt) or two chemically distinct members. A strong gradient in heterogeneity power of a laterally heterogeneous perturbation, superposed on a a laterally homogeneous ultra-low velocity zone, can produce an apparent anisotropy of SH and SV wavefields. Computational experiments also demonstrate that small scale ($<$100 km) heterogeneity can contribute to a pulse delay and broadening of body waves similar to that of intrinsic attenuation.
UR: http://www.sp.uconn.edu/~cormier
DE: 7203 Body wave propagation
DE: 7207 Core and mantle
DE: 7260 Theory and modeling
DE: 8124 Earth's interior--composition and state (old 8105)
SC: Seismology [S]
MN: 2003 Fall Meeting