GPR velocity and amplitude analyses to characterize the stratigraphy and estimate the ice density: An example from the Eastern Glacier of Mt. Canin (Alpine Chain, Italy)

Abstract

We propose a methodology to estimate the density of frozen media (snow, firn and ice) using common offset GPR data. The technique bases on reflection amplitude analysis to calculate the series of reflection coefficients. The latter is used to estimate the electrical permittivity (dielectric constant) of each level. Applying one of the empirical equations available from the literature is possible to determine the vertical density variations for all the acquired GPR traces and therefore infer the nature of frozen materials (from fresh snow, to granular snow, firn and ice) and to estimate the Snow Water Equivalent (SWE), which is an essential parameter to determine the actual water volume within a certain frozen body. The proposed technique was tested in the Eastern Glacier of Mt. Canin (Eastern Alps) and validated by direct snow density measures, obtained using samples collected from manually dug snow pits, and with data from the literature. Despite the necessary approximations, the average value of density for different levels is calculated with acceptable accuracy. Moreover, this analysis can help to find and locate debris/moraines embedded within the ice bodies.