Pre-stack waveform inversion of VHF marine seismic data. A case study in Norway

A quantitative physical model of the shallow marine sediments is of crucial importance in broad range of environmental and engineering contexts, from the assessment of tsunamigenic landslides hazard and off-shore structure stability, to the identification and monitoring of carbon capture and storage sites. However, in contrast to reservoir geophysics, where quantitative seismic interpretation and inversion are extensively employed tools, sub-seabed characterisation is still heavily reliant on direct samplings, using cores, boreholes and CPTUs. In this context, the role of seismic reflection is often limited to a mostly qualitative interpretation of the reflection architecture.Here we will present the first published application of pre-stack elastic full waveform inversion to a Very-High-Frequency (VHF, 0.4 – 2.5 kHz) multi-channel seismic reflection dataset. A custom-built local multi-parameter sequential waveform inversion method has been developed and tested on two common-shot gathers from a multi-channel Boomer seismic profile acquired in northern Norway. The decimetre-resolution impedance and Poisson’s ratio obtained models strongly agree with the a-priori geotechnical and geological information available in the area, proving the potential of the method in obtaining an accurate remote characterisation of the shallow sediments within a reasonable computational cost and using a traditional multi-channel sub-bottom profiler