GPR Profile of Beacon Valley, Dry Valleys, Antarctica: Analysis of the GPR Response from Rocky Permafrost

摘要

Results of ground penetrating radar (GPR) profiling of Beacon Valley in Antarctica suggests that significant quantities of ice are present. A more detailed analysis of widespread diffractions highlights the large variations in the GPR velocity, both laterally and with depth. The dominant aspect of the data is the strong layering of the velocity, with high velocities (0.13 ms or greater) in the upper approximately 200 ns (about 13 metres) and low velocities (0.11 ms or less) below. The most striking feature is a near vertical zone of low velocities, as low as 0.07 ms, which appears as a set of diffractions that are “stacked” one above another. Such a structure is interpreted as a larger-than-normal crack formed in permafrost polygonal patterned ground or possibly a relict crevasse.