Repeated Electrical Resistivity Tomographies in a CALM Site in Livingston Island, Maritime Antarctica

During the years of 2009, 2012, and 2013 several electrical resistivity tomographies (ERTs) were done in a CALM (Circumpolar Active Layer Monitoring) site near the Bulgarian Antarctic Base of St. Kliment Ohridski. The main objective of the ERTs was to try to identify permafrost zones and their extension, as well as their time and space evolution. Geoelectrical methods, in particular ERTs, are very useful for permafrost studies because of the significant increase of the electrical resistivity when the ground is partially or totally frozen and when temperature is lower than 0 degrees celcius. For each ERT made, 40 electrodes in line, spaced by 2 metres each, were used and the apparent electrical resistivity measurements were mathematically inverted to obtain two-dimensional geoelectrical models for each of them. All models show high electrical resistivity values (of the order of tens of thousands of Ω.m). In the CALM site the high electrical resistivities probably correspond to patches of frozen ground but it is not possible to indicate whether it is sporadic permafrost or remnants of seasonally frozen ground yet.