Russian geophysical studies of Lake Vostok, Central East Antarctica

Since 1995, Polar Marine Geological Research Expedition has performed the geophysical investigations of Lake Vostok, Central East Antarctica. The study of this phenomenon is carried out by means of radio-echo sounding (RES) and reflection seismic. In total, 3 250 km of RES profiles and 194 seismic measurements have been made. These scientific works resulted in mapping the ice thickness, bedrock and sub-ice topography and the Lake Vostok shoreline. We fixed 195 fragments of grounding line, according to RES data, with 169 of them (86%) being reliable while 26 (14%) are questionable. These results are the base for contouring the lake shore. The water table square estimates at some 17 100 km(2). We also detected 22 small-size subglacial water cavities around the Lake Vostok. Sub-ice topography of the Lake Vostok bottom is divided into two main regions:the deep-water and shallow-water basins. The first one with depths from about -1700 to -800 m is located in the southern part of the lake. We assume its northern part to be shallow-water with the bottom depth of about -940 m.