Death of a Moai

Dr. A. Elena Charola, consultant to the World Monuments Fund Easter Island Program, reports on the creation, installation and mechanisms of deterioration for the large stone sculptures, or moai, and associated petroglyphs carved of Rano Raraku tuff. Weathering from exposure to wind and water, alveolar deterioration induced by the recrystallization of water-born salts, differences in mechanical performance between the tuff and basalt inclusions, the growth of algae and lichens on stone surfaces, and the introduction of free-roaming sheep and cows have all contributed to the decline of the cultural heritage sites on the island. Subsequent conservation work and the reinstallation of many of the moai on their stone altars, or ahu, were completed with cement-based mortar, acting as a water barrier and prolonging dampness along the base of the statues. This report concludes by advocating for the periodic treatment and consolidation of the moai with a solution of Wacker OH, modified with less volatile solvents to extend drying time and a fungicide to kill organic growth on the stone surface.