Abstract

Detection of crevasses is critical for safe travelling on glaciers. Here we present the use of a Ground Penetrating Radar (GPR) for crevasse detection. Experiments were made in temperate ice on Glacier Mocho, Volcán Mocho-Choshuenco, southern Chile (39°25?S) and in cold ice in East Antarctica (87°30?S). In southern Chile the radar was hand-carried 1.2 m in front of the operator who was walking over the glacier at a speed of ?0.5 m s-1, while in Antarctica it was mounted on a 7-m long rod in front of a tractor convoy travelling at a speed of ?2 m s-1. In both geographical sites profiles were made perpendicularly to crevasses ranging in width from 0.1 m to 1.0 m. Buried crevasses clearly show as apexes of diffraction hyperbolae, which could be detected down to a depth of 15 m. They show as discontinuities in the firn stratigraphy which have a width equal to the crevasse width, and associated diffraction hyperbolae to each side of the crevasse. The GPR proved to be a valuable tool for detecting crevasses, allowing for a reaction time of ?9 s (equivalent to ?4.5 m on the ground) in the case of the hand-carried system and ?5 s (or ?10 m on the ground) for the tractor system. Copyright © 2007 IAHS Press.