Five seismic reflection profiles (Lake A to E) were acquired across Subglacial Lake Ellsworth (SLE), Antarctica, during the 2007-08 austral summer. SLE is a freshwater lake that lies under ice that is ~3.2 km thick. SLE is approximately 15 km long and 3 km wide. The data were acquired to determine the overlying ice thickness, the water depth in the lake, and the lake-bed material. The seismic lines were aligned perpendicular to the lake's long axis and spaced roughly 1.4 km apart, over what appears to be the deeper part of the lake. Seismic shot-point locations were determined using RTK GPS methods. Seismic sources were Pentolite explosives in 30 m deep holes made with a hot-water drill and backfilled with snow. The fieldwork was a collaboration between the British Antarctic Survey (BAS), Northumbria University and the University of Edinburgh. Funding was provided by NERC AFI awards NE/D009200/1, NE/D008638/1 and NE/D008751/1. Equipment support by NERC Geophysical Equipment Facility loan numbers 838 and 870.

Subglacial Lake CECs was previously identified using radar profile data. Subglacial Lake CECs lies beneath 2650 m of ice, close to the Ellsworth Mountains at the divide between the Minnesota Glacier and Rutford and Institute Ice Streams in Antarctica. Four seismic reflection profiles were acquired across the lake to determine water column depth and investigate lake bed properties. Shot gathers with 48 channels and a maximum offset of 500 m were recorded. A seismic refraction experiment was undertaken to determine seismic velocities in the firn. Dual frequency and RTK GPS were used to determine shot locations. Seismic surveys indicate a maximum water depth of 301.3 +/- 1.5 m, at the widest part of the lake, with an estimated lake volume of 2.5 +/- 0.3 km3. Imaging of the ice-lake interface indicates topography with slopes of up to 1.9 degrees. This research was supported by the Natural Environment Research Council, British Antarctic Survey (Polar Science for Planet Earth Programme) and Centro de Estudios Cientificos, Valdivia, Chile.