Inversion of Seabed Geotechnical Properties in the Arctic Chukchi Deep Sea Basin Based on Time Domain Adaptive Search Matching Algorithm

The chirp sub-bottom profiler, for its high resolution, easy accessibility and cost-effectiveness, has been widely used in acoustic detection. In this paper, the acoustic impedance and grain size compositions were obtained based on the chirp sub-bottom profiler data collected in the Chukchi Plateau area during the 11th Arctic Expedition of China. The time-domain adaptive search matching algorithm was used and validated on our established theoretical model. The misfit between the inversion result and the theoretical model is less than 0.067%. The grain size was calculated according to the empirical relationship between the acoustic impedance and the grain size of the sediment. The average acoustic impedance of sub-seafloor strata is 2.5026 × 10⁶ kg (s m²)⁻¹ and the average grain size (θ value) of the seafloor surface sediment is 7.1498, indicating the predominant occurrence of very fine silt sediment in the study area. Comparison of the inversion results and the laboratory measurements of nearby borehole samples shows that they are in general agreement.