Near-surface imaging in frozen environments using GPR

Monica Moldoveanu-Constantinescu, Robert R. Stewart

This paper describes ground-penetrating radar (GPR) surveys that were conducted to characterize the ice and shallow subsurface of a frozen lagoon at Bowness Park, Calgary. We used Sensors and Software Inc.'s 250 MHz NOGGIN and SmartCart system as well as a Pulse EKKO 4 system with a 100 MHz antenna to acquire GPR surveys over the frozen lagoon in two consecutive years (2003 and 2004). Hyperbolic velocity analysis gave ice velocities of about 0.15 m/ns with velocities decreasing in the sediments to about 0.11 m/ns. We interpret the ice thickness to be about 0.4 meters from the GPR profiles, which is consistent with augur holes drilled through the ice. Channel sediments and stratigraphy beneath the ice are interpretable from the 3D radar reflectivity. We located and mapped a paleochannel with a NW-SE orientation and a thickness of about 0.5 meters. Penetration of the 250 MHz data reached about 2 meters at several locations in the area.