Site survey for the Pierre Auger observatory

Within the framework of the Pierre Auger project, it was necessary to identify suitable places for the observatory sites and to characterize them in order to make a final selection. 'Pampa Amarilla' in the province of Mendoza, Argentina and Millard County, State of Utah, USA have been chosen for the southern and northern sites, respectively. Atmospheric, meteorological, soil and topography studies were performed at those sites.