Ronan Samuel Agnew, Roger Clark, Adam Booth , Alex Brisbourne, Andrew Smith

We present seismic measurements of the firn column at Korff Ice Rise, West Antarctica, including measurements of compressional- and shear-wave velocity and attenuation. We describe a modified spectral-ratio method of measuring the seismic quality factor (Q) based on analysis of diving waves, which enables us to characterise the attenuative structure of firn in greater detail than has previously been possible. The compressional-wave quality factor, Qp, increases from 20 ± 10 in the uppermost firn to 423 ± 260 between 77 and 86 m depth, and the shear-wave quality factor, Qs, increases from 16 ± 9 in the uppermost firn to 100 ± 87 between 49 and 64 m depth. Our modified spectral-ratio method aids the understanding of the seismic structure of firn and benefits characterisation of deeper glaciological targets, being particularly impactful for correcting reflection amplitudes in wide-angle seismic data.