Setting up a GPS monument at the 'HELZ' site. Emily Desmarais using GPS to map some of the Erebus fumaroles. Jean Wardell and Noel Barstow installing a GPS antenna at the lower Erebus hut. Bjorn Johns drilling a hole for a GPS monument. A Trimble GPS unit that Jean Wardell used to precisely track her gas sampling flight through the Erebus plume. Emily Desmarais using a Trimble GPS to map some of the Erebus ice towers. Phil Kyle and Chuck Kurnik installing a GPS monument at 'EAST'. Emily Desmarais using a Trimble GPS and a skidoo to map some of the ice towers in the summit region of Mt. Erebus. Beth Bartel and Phil Kyle installing a GPS monument on the caldera rim of Mt. Erebus. Beth Bartel installing a GPS monument at Abbott Peak (Mt. Bird in the background).