Seismic investigation of a subglacial lake

Field Team includes:

Alex Brisbourne (BAS), Andrés Rivera (CECs), Rodrigo Zamora (CECs), Field Guide (BAS).

Antarctic subglacial lakes contain unique records of ice sheet history and microbial life; they may also act as large reservoirs of water that lubricate the ice sheet flowing over its bed and are potentially useful analogues for extra-terrestrial life. For these reasons, subglacial lakes are the subject of much scientific interest and much effort has been put into investigating them.

To gain the maximum scientific benefit from subglacial lakes requires drilling into them so that lake water and sediments at the bed can be sampled. But no plans for subglacial lake access should be made without prior geophysical surveys to confirm its presence, determine its physiography and characteristics, and guide the optimum location for any access holes.

Two of the critical things that geophysical surveys can do is to confirm a subglacial lake actually exists and measure how deep the water is; the only way to measure the water depth is with seismic methods. Colleagues from Centro Estudios Cientificos (CECs) in Chile have identified a subglacial lake West of the Ellsworth Mountains (Subglacial Lake CECS, or SLC; see location map). As part of the 2016/17 field season, BAS and CECs will collaborate to do a seismic survey of SLC with the main goal of finding out how deep the water is. Seismic surveys involve detonating small explosive charges and recording the echoes that are reflected back off the top and bottom of the lake.

This work is in collaboration with Chilean colleagues in Valdivia http://www.cecs.cl/website/index.php/en/component/content/article/12-glaciologia-y-cambio-climatico/503-laboratorio-de-glaciologia