Methodology:

Five seismic reflection profiles were acquired. The seismic source was 450 g explosives at 30 m depth. Shot spacing was 240 m, number of channels was 48 and geophone spacing was 10 m, resulting in single-fold data. Data processing included normal moveout correction, and migration. Ice-water and water-bed interface reflections were picked from stacked seismic sections. Depth conversion used a travel-time correction for the upper snow and firn, and standard ice- and water-column velocities. Full details of data acquisition and processing are given in:

Woodward, J., A. M. Smith, N. Ross, M. Thoma, H. F. J. Corr, E. C. King, M. A. King, K. Grosfeld, M. Tranter, M. J. Siegert, 2010. Location for direct access to subglacial Lake Ellsworth: An assessment of geophysical data and modelling. Geophysical Research Letters, doi:10.1029/2010GL042884.

Smith, A.M., J. Woodward, N. Ross, M.J. Bentley, D.A. Hodgson, M.J. Siegert, E.C. King, 2018. Evidence for the long-term sedimentary environment in an Antarctic subglacial lake. Earth and Planetary Science Letters, doi:10.1016/j.epsl.2018.10.011.

Data collection:

Seismic data were acquired with Geometrics Geode seismographs; data processing and picking were done with Landmark ProMAX.

Data quality:

Data quality are good; the ice-water interface can be clearly picked on virtually all traces, the water-bed interface can be picked in most places, except close to the lake shoreline and at a few other locations on each line. Only the results from traces where both reflections can be picked are provided. Nominal point spacing is 5 m, with occasional gaps at the locations where both reflections could not be picked. Absolute errors in ice- and water-column thickness are 10 m and 1.5 m respectively, although relative thicknesses changes (trace-to-trace) are more precise. See publications for full details.