Estimating changes in scattering strength in a 2D multiply-scattering medium
S. Van Meulebrouck (TU Delft - Civil Engineering & Geosciences)
K. Löer (TU Delft - Civil Engineering & Geosciences)
H. Douma (Quantairra Research and Development Services B.V.)
E. Verschuur (TU Delft - Civil Engineering & Geosciences)
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Abstract
This work explores how changes in scattering strength in multiply-scattering media can be quantified using synthetic wavefields computed with Foldy's method for isotropic point scatterers. By averaging waves across random realizations, the effective complex wavenumber, which is linked to the scattering strength through the effective attenuation and phase velocity, can be estimated. We estimate the attenuation coefficient from average recordings at different offsets. Simulations show that the attenuation coefficient can be reliably calculated for a wide frequency band around the central frequency of the source wavelet, but that accuracy declines at low and high frequencies due to model and source spectrum limitations. The method currently applies only to 2D isotropic point scatterers with constant scattering amplitude and assumes the scatterer number density to be known, but the extension to estimating relative changes in scattering strength for models with varying scattering amplitudes but equal scatterer number density is straightforward.