Seismic evidence for a water‐filled canal in deforming till beneath Rutford Ice Stream, West Antarctica

Seismic data from Rutford Ice Stream, West Antarctica show high amplitude, reversed‐polarity reflections from parts of the bed. Only interfaces between ice and water, or between water and sediment have the acoustic properties to produce such strong reflections – ice/sediment interfaces produce much weaker echoes. The evidence suggests that an area of the ice stream measuring at least 1 km by 0.2 km is underlain by water with a depth of less than 1 m. The data are consistent with the presence of a sub‐ice drainage system comprising shallow canals cut into the sedimentary substrate, as predicted by theory.