1 GROUND PENETRATING RADAR AS AN INVESTIGATIVE TOOL: EXPLORING HUMAN-MODIFIED TO NATURAL ENVIRONMENTS Frontiers Abroad 2008, University of Auckland Mindi Summers, Stanford University Geological and Environmental Sciences, 2009 Dan Hikuroa Darren Gravely INTRODUCTION Ground penetrating radar (GPR) is a recent geotechnical technique used to observe subsurface stratigraphy in a continuous transect. GPR emits short pulses of electromagnetic energy into the ground that are reflected back to the receiver according to the dielectric permittivity of the sediments below. Prominent reflectors within the sediment are then used to construct a GPR profile that can then be interpreted to yield information on depositional history. GPR has been used in a variety of settings outlined by Neal (2004). This study continues to explore the questions that GPR can answer in different environmental settings. GPR profiles from three sites that range from completely human induced to natural are interpreted and discussed to test the applicability of using GPR in the following three situations: 1. To locate buried chemical drums in the solid waste embankment at Norske Skog Pulp and Paper Mill. 2. To show evidence of a prior river channel now buried by a natural dune following human channeling and redirection of the Tarawera River. 3. To investigate the evolution of a natural prograding barrier system within the Rangitaiki Plains.