Abstract

New surveys and samplings have been carried out in Easter Island to advance the hydrogeological knowledge of small, relatively recent volcanic islands. From the work being done, tritium data have been selected from the scarce points of access to the aquifer, and from the dripping inside three shallow volcanic tubes, to be compared to precipitation data, in order to get the aquifer recharge. A value of about 300 mm/year is obtained, which may be reduced to 150 mm/year in the western side. The value is coherent, in spite of the high uncertainty, with what can be expected. The applied methodology is usable in other circumstances.