2025_programme: Trans-dimensional matched-field inversion for compressional and shear geoacoustic profiles
- Day: June 16, Monday
Location / Time: B. ERATO at 12:20-12:40
- Last minutes changes: -
- Session: 07. Inverse Problems in Acoustical Oceanography
Organiser(s): Julien Bonnel, Stan Dosso
Chairperson(s): Julien Bonnel, Stan Dosso
- Lecture: Trans-dimensional matched-field inversion for compressional and shear geoacoustic profiles
Paper ID: 2119
Author(s): Stan Dosso, Julien Bonnel
Presenter: Stan Dosso
Abstract: This paper estimates depth-dependent profiles of compressional- and shear-wave geoacoustic properties for seabed sediments through matched-field inversion of broadband (20-2000 Hz) acoustic data recorded at a vertical line array due to an impulsive sound source on the New England Mud Patch. Trans-dimensional (trans-D) Bayesian inversion is applied to sample probabilistically over the number of seabed layers and corresponding layer depths and geoacoustic properties, as well as over the order and parameters of an autoregressive error model. This inversion is based on reversible-jump Markov-chain Monte Carlo sampling, which combines objective, data-driven model selection and quantitative parameter/uncertainty estimation. The large number of parameters per layer (six: interface depth, density, and compressional- and shear-wave speeds and attenuations) makes acceptance of dimension jumps (changes to the number of layers) challenging, and an intensive parallel tempering scheme combined with principle-component reparameterization is applied to improve efficiency. Inversion results indicate low shear-wave speeds (~35 m/s) with relatively-small uncertainties over the upper mud layer, increasing in underlying transition and sand layers. The compressional-wave attenuation profile is well estimated but shear-wave attenuation is poorly constrained. Comparison of results for inversions both with and without shear-wave parameters and consideration of inter-parameter correlations indicate that estimates of compressional-wave parameters, including attenuation, are not substantially influenced by shear-wave effects, with the possible exception of the sand layer.
- Corresponding author: Prof Stan Dosso
Affiliation: University of Victoria
Country: Canada
