Full elastic inversion of multioffset marine data on a stratified medium

Inversion of multioffset marine data requires an accurate modeling of the "real earth". A full elastic modeling for horizontally stratified medium (1-D) has been developed to simulate the marine wavefield including all multiples and converted waves. The P-wave velocity, S-wave velocity and density models are then estimated as function of traveltimes through an optimization problem based on a least-squares formalism. The: nversion algorithm is applied on large scale noise-free multioffset data computed from a 1-D fluid-solid medium. Velocity analysis gives the initial P-velocity model; the S-velocity and density models follow from experimental laws. Cycles of frequency and time continuations are carried out. The inversion results are analysed through the choice of the initial models and through the resolvability of the different elastic parameters. Finally, practical applications of the full elastic inversion on marine field data are discussed.