Bayesian geoacoustic inversion using mixture density network
This provides a more efficient approach for real-time geoacoustic inversion, though it is incremental as it extends an existing framework with a neural network method.
The paper tackles the computational expense of Bayesian geoacoustic inversion by using a mixture density network to derive geoacoustic statistics from the posterior probability density, enabling rapid (within seconds) probabilistic solutions comparable to Monte Carlo methods.
Bayesian geoacoustic inversion problems are conventionally solved by Markov chain Monte Carlo methods or its variants, which are computationally expensive. This paper extends the classic Bayesian geoacoustic inversion framework by deriving important geoacoustic statistics of Bayesian geoacoustic inversion from the multidimensional posterior probability density (PPD) using the mixture density network (MDN) theory. These statistics make it convenient to train the network directly on the whole parameter space and get the multidimensional PPD of model parameters. The present approach provides a much more efficient way to solve geoacoustic inversion problems in Bayesian inference framework. The network is trained on a simulated dataset of surface-wave dispersion curves with shear-wave velocities as labels and tested on both synthetic and real data cases. The results show that the network gives reliable predictions and has good generalization performance on unseen data. Once trained, the network can rapidly (within seconds) give a fully probabilistic solution which is comparable to Monte Carlo methods. It provides an promising approach for real-time inversion.