9419267 Kyle and Aster Abstract This award supports continuation of the Mount Erebus Volcano Observatory. The principal objectives are to continue year-round surveillance of the volcanic activity of Mount Erebus, using a network of 7 seismic stations and gas monitoring during summer months. The seismicity will provide an understanding of the eruptive behavior and dynamics of Mt. Erebus. Inversion of the seismic data in future may allow tomographic imaging of the magma chamber and plumbing inside the volcano. During the austral summer months, field based observations will include measuring emission rates of sulfur dioxide (SO2) and trace gases and metals. These data will be used to evaluate the potential impact of gas emission from Erebus on the snow chemistry on the East Antarctic Ice Sheet. Short term variations in the emission rates of F, Cl, SO2 and metals will be examined to infer volatile zoning in the magma chamber supplying the lava lake. A separate program of radiometric dating using the high precision 40Ar/39Ar method will be coordinated with this work to determine the geological evolution of the volcano and to examine eruption rates of anorthoclase phonolite lavas from Mt. Erebus.