Broadband geoacoustic inversion from sparse data using genetic algorithms

Matched-held acoustic inversion techniques were investigated using data fro m sparsely populated vertical receiving arrays and a single receiver elemen t. The purpose of considering sparse data sets is to investigate, under sim ulation, the feasibility of reducing the number and complexity of acoustic measurements needed for geoacoustic inversion. The entire bandwidth of the 1997 Geoacoustic Inversion Workshop provided data (25-500 Bz) was used whic h compensates for the lack of spatial information when a limited number of receivers is considered. The forward model PROSIM and inversion code SAGA w ere applied to benchmark cases: sd, wa, and n. The inversion results genera lly showed good agreement with the ground truth for full arrays, sparse arr ays and single receiver elements. With a simple two-layer model, an effecti ve sound speed profile in the bottom was determined which produced a good f it between the model and observed pressure fields for the multi-layer case n.