HR: 11:00h
AN: S32A-03    [Abstracts]
TI: Coda Wave Correlation in an Analogous Crust at Ultrasonic Frequency
AU: * Derode, A
EM: arnaud.derode@loa.espci.fr
AF: Laboratoire Ondes et Acoustique-Universite D. Diderot, 10 rue Vauquelin, PARIS, 75231 France
AU: LAROSE, E
EM: eric.larose@ujf-grenoble.fr
AF: Laboratoire de Geophysique Interne et Tectonophysique- Universite J. Fourier, BP 53, GRENOBLE, 38 041 France
AU: Clorennec, D
EM: dominique.clorennec@loa.espci.fr
AF: Laboratoire Ondes et Acoustique-Universite D. Diderot, 10 rue Vauquelin, PARIS, 75231 France
AU: MARGERIN, L
EM: ludovic.margerin@ujf-grenoble.fr
AF: Laboratoire de Geophysique Interne et Tectonophysique- Universite J. Fourier, BP 53, GRENOBLE, 38 041 France
AU: Campillo, M
EM: michel.campillo@ujf-grenoble.fr
AF: Laboratoire de Geophysique Interne et Tectonophysique- Universite J. Fourier, BP 53, GRENOBLE, 38 041 France
AB: The Earth's crust is often thought of as a complex medium with random heterogeneities from which the seismic coda (the late arrivals following the direct waves) takes form. Recently, it was found that cross-correlation of diffuse fields (like crustal coda) yield the Green's function between two passive sensors. This is the first step to achieve passive imaging with diffuse fields or noise. To get rid of field experiment limitations like sensor synchronizing or variation of the seismic source, we propose an analogous experiment at the scale 1:10^-6.The cross correlation technique is applied to elastic ultrasonic waves in an open scattering slab mimicking seismic waves in the crust. It appears that the Rayleigh wave reconstruction depends on the scattering properties of the elastic slab. Special attention is paid to the specific role of bulk to Rayleigh wave coupling, which may result in unexpected phenomena like a persistent time-asymmetry in the diffuse regime. Cross-correlation of bulk coda also emerges as a possible way to localize buried scatterers and quantify their relative strength.
DE: 3270 Time series analysis (1872, 4277, 4475)
DE: 7255 Surface waves and free oscillations
DE: 7260 Theory
SC: Seismology [S]
MN: Fall Meeting 2005