To date, state-of-the-art seismic material parameter estimates from
multi-component sea-bed seismic data are based on the assumption
that the sea-bed consists of a fully elastic half-space. In reality,
however, the shallow sea-bed generally consists of soft, unconsolidated
sediments that are characterized by strong to very strong seismic
attenuation. To explore the potential implications, we apply a state-of-the-art
elastic decomposition algorithm to synthetic data for a range of
canonical sea-bed models consisting of a viscoelastic half-space
of varying attenuation. We find that in the presence of strong seismic
attenuation, as quantified by Q-values of 10 or less, significant
errors arise in the conventional elastic estimation of seismic properties.
Tests on synthetic data indicate that these errors can be largely
avoided by accounting for the inherent attenuation of the seafloor
when estimating the seismic parameters. This can be achieved by replacing
the real-valued expressions for the elastic moduli in the governing
equations in the parameter estimation by their complex-valued viscoelastic
equivalents. The practical application of our parameter procedure
yields realistic estimates of the elastic seismic material properties
of the shallow sea-bed, while the corresponding Q-estimates seem
to be biased towards too low values, particularly for S-waves. Given
that the estimation of inelastic material parameters is notoriously
difficult, particularly in the immediate vicinity of the sea-bed,
this is expected to be of interest and importance for civil and ocean
engineering purposes.