HR: 09:10h
AN: S31C-05    [Abstracts]
TI: Displacement Gradient Analysis of Array Seismic Data
AU: * Langston, C A
EM: clangstn@memphis.edu
AF: Center for Earthquake Research and Information, University of Memphis, 3876 Central Ave., Suite 1, Memphis, TN 38152 United States
AB: Amplitudes of multi component seismic array data can be used to derive temporally and spatially dependent images of phase velocity, geometrical spreading and anelastic attenuation using displacement gradient analysis. The displacement gradient is physically related to material strains and can be cast into a seismologically useful tool using simple, but general, wave propagation models. The displacement gradient for a propagating phase generally consists of two terms: one containing the normalized geometrical spreading associated with ground displacement and the other a phase velocity term associated with ground velocity. Array analysis consists of computing displacement gradient time series from the array geometry and finding the geometrical spreading and phase velocity coefficients of the displacement and velocity time series. Point source, plane wave, body wave and surface wave wave fields are considered in the time domain analysis. Anelastic attenuation may also be studied in a similar way using the spectra of the displacement and displacement gradient. This technique can provide images of geometrical spreading, phase velocity, and Q from spatially sampled seismic wave fields found in a variety of experimental geometries including seismic refraction, reflection, near-field strong motion arrays, and regional seismic arrays.
DE: 0902 Computational methods: seismic
DE: 0935 Seismic methods (3025, 7294)
SC: Seismology [S]
MN: Fall Meeting 2005